Wikia

Scratchpad

Dtse2007:Photosynthesis

Discuss this page0
165,226pages on
this wiki

Photosynthesis

Demographics

Gender Age / Grade Bio-background
Female 17 / 12 Advanced Biology / Advanced Chemistry
Male 18 / 12 Advanced Biology / Advanced Chemistry
Female 15 / 10 Biology / General Science
Female 17 / 12 Honors Biology / Chemistry with Lab / Advanced Biology
Male 17 / 12 Biology / Chemistry / Earth Science
Female 17 / 12 Biology / Chemistry / Earth Science
Female 16 / 10 Biology
Male 16 / 10 AP Biology / AP Chemistry
Female 11 / 6 General Science
Female 12 / 7 Biology / General Science
Female 13 / 8 Biology / General Science
Female 13 / 8 Biology / General Science

Objectives

  • SWBAT identify and describe different types of energy and understand conversion of solar energy to chemical energy.
  • Energy cannot be created or destroyed. It can only be converted from one type to another.
  • Energy is not a “thing”. Energy is the capacity of a system to do work.
  • Understand the difference between Work, Force and Energy.
  • SWBAT define and explain what an autotroph and heterotroph are and their roles in the ecosystem.
  • Autotrophs are the only organisms that can produce their own food.
  • Energy is stored in an autotroph and then transferred to different trophic levels.
  • The interdependence of organisms in a food web.
  • SWBAT draw and label the parts of a chloroplast, including chlorophyll pigments and understand their role in photosynthesis.
  • Understand wavelengths, the color spectrum and refraction and absorption of light.
  • SWBAT define and explain the equation of photosynthesis (its reactants and products) and various factors that affect the rate of photosynthesis.
  • Emphasize the production of glucose as the purpose of photosynthesis and oxygen as a byproduct.
  • SWBAT define and explain the two pathways light and dark reactions (Calvin Cycle).
  • Light and dark reactions are two parts of the photosynthesis equation.

Protocol

  1. Can you tell me what energy is? Where does energy come from?
  2. (If they do not mention solar energy) Is light a form of energy?
  3. What do plants need to survive? Draw it. Why?
  4. Why do you think they need: water……light……soil. How it happens?
  5. Do you know where plants get their food? Is it similar to how humans get their food?
  6. (If they mention Sun) How does the Sun help the plants?
  7. (If say make food from Sun) How do you think that happens?
  8. What happens with the plant if you put it in a dark place?
  9. Why are leaves green?
  10. Why are plants needed in the environment?


Possible follow up questions: How do you think it happens? Can you tell me what that/it means?

Summary

Energy This was the most difficult concept for the students to understand. Every student mentioned the word force; some mentioned work or motion. Typical answers were, “It’s a force…a force that is found in nature”, and “a force, um power and things that move or things that involve moving them”. They seemed to think that energy is a thing that is either created or found in nature. They intuitively knew that there were different types of energy and could name some types but beyond that they were very confused. None of them understood how energy was converted. Some of them had a notion of a “change” or “reaction”. Some of them thought that light itself was the food for the plant and only a few understood that it is used to make food.

Instruction: We need to make sure that students understand the difference between energy, work and force, how energy is actually converted and be able to define and explain the types of energy.

Autotrophs and Heterotrophs Most of the students did not understand why plants do photosynthesis. They thought the main reason for the photosynthetic process was oxygen production. They did not understand the idea of a food web or relate other organisms to the role of plants. They mainly referred to a plant’s role as fulfilling our need to breath. Only one student referred to the medicinal benefits of plants.

Instruction: The students need to understand the complexity of a food web and the idea of interdependence beyond human beings.

Chlorophyll in Photosynthesis. Students confused chloroplast with chlorophyll. Most of them knew it could be found in leaves but didn’t understand its role in photosynthesis. Only a few of the students knew the leaves were green because of chlorophyll or chloroplast. Three students knew that photosynthesis took place in chloroplast. These three students mentioned different light waves and something to do with color but couldn’t put it into the why the leaves are green.

Instruction: We need to work a bit on the chemistry inside the chloroplast for the students to understand how the conversion of energy is done.

Photosynthesis equation. Factors affecting its rate. Only six out of twelve students knew that glucose is the end product produced in photosynthesis. The products and reactants were not clear and therefore they could not expand on what would affect the rate of the plants production. Most of them understood there was a process and a change involved but couldn’t explain it fully.

Instruction: We need to help the students become familiar with describing a chemical equation and the inputs and outputs of the photosynthesis reaction. Also, because of the idea that oxygen seemed to be the “purpose” of photosynthesis, we need to focus on the significance of the glucose production-that plants do it for themselves, not for us or anything else.

Light/Dark reaction: Not part of the interview process.

Instruction: These are terms and ideas the students should be familiar with but they are not part of the enduring ideas of this unit. The kids should understand that the dark reaction does not occur in the dark or only at night but is the second phase of the light reaction and both are needed to produce glucose.

Technology PowerPoint used for lecture Animations for photosynthesis simulation


Executive Summary

Photosynthesis is not one of the most important chemical processes ever developed by life. It ultimately powers all the living things. With this in mind we designed a series of lessons that would not only engage and motivate students but also allow them to fully appreciate the significance of this concept. The content part of the design was strictly guided by the NJ state curriculum standards. We decided to take on a new approach to teaching the complexities of photosynthesis. Instead of having students listen to lectures or perform recipe style labs we asked them to use their imagination. We came up with an alien scenario in which the occupants of a “newly discovered planet” obtain energy from unknown source. Aliens are analogous to plants on Earth. Students pretend to be scientists. They work in groups on developing a hypothesis about the mechanism by which alien species obtain energy. We incorporated Nature of Science into activities in order to familiarize students with the way real scientists approach similar problems. As the result of their investigation, students discover the connection between aliens and plants. By then they would have developed a true appreciation of photosynthesis and would be sufficiently motivated to learn even the tedious aspects of this process.

Curriculum Overview

The learning objectives for this unit are:

1. SWBAT identify and describe different types of energy and understand they can be converted from one to another. Energy cannot be created or destroyed. It can only be converted from one type to another.

2. SWBAT define and explain what an autotroph and heterotroph are and understand the role of autotrophs in the ecosystem. Autotrophs are the only organisms that can produce their own food.

3. SWBAT draw and label the parts of a chloroplast, including chlorophyll pigments and understand their role in photosynthesis.

4. SWBAT define and explain the equation of photosynthesis (its reactants and products). Emphasize the production of glucose as the purpose of photosynthesis and oxygen as a byproduct.

5. SWBAT list various factors that affect the rate of photosynthesis and explain how they do that. (Temperature, Light Intensity, Carbon Dioxide Concentration)

6. SWBAT define and explain the two pathways light and dark reactions (Calvin Cycle). Light and dark reactions are two parts of the photosynthesis equation. What happens in the dark? The evolution of C4 and CAM plants.

7. SWBAT explain what scientific models are and how scientists use them.

The Backbone

The following is the backbone outlining the entire unit.

Driving macrostructure

Propose the mechanism by which Qs obtain energy. Support your hypothesis from the collected data and provide an explanation.

Nested structure 1

How do Qs get their energy?

Lesson 1.1

Students are presented with the alien scenario and the task of creating a model of how the Qs are obtaining their energy. Students are introduced to the use of models in scientific research. The characteristics of a good model will be discussed and examples shown.

Lesson 1.2

The concept of energy is fully introduced. Students learn that energy cannot be created or destroyed. Students discuss the relationship between energy and food and the concept that energy can change forms.

Nested structure 2

Students will begin to explore all the inputs and the outputs of the alien organisms to create a model of energy acquisition by the aliens.

Lesson 2.1

Students should determine for themselves what they consider an input or output. Focus on the vat of nutrients, CO2, and water. If these were not brought up by the students they may need to be redirected. Students investigate the data supporting or refuting these elements as possible sources of energy. The students begin to fill in a chart to organize their findings and develop their models.

Lesson 2.2

Students are directed to focus on the alien data concerning light, O2, and glucose. Students investigate the data supporting or refuting these elements as possible sources of energy. The chart and their models should be worked on to completion.

Nested Structure 3

Students present their alien models. The alien models are compared to how plants obtain energy and the process photosynthesis.

Lesson 3.1

Students share and discuss the models they created to explain how the Q’s obtain energy. The mechanism for how the Q’s obtain energy developed by the students will now be connected to how plants obtain energy. The process of photosynthesis will be introduced. Students will continue to revise their alien models for the rest of the unit based on the information they learn from the study of photosynthesis.

Nested Structure 4

Students begin to study the process of photosynthesis in more detail; its reactants and products, the role of pigments, light and dark reactions, Cam plants, and the factors that affect the rate of photosynthesis.

Lesson 4.1

Students discuss reactants and products of photosynthesis with accompanying lab.

Lesson 4.2

Students examine the role of pigments and light in photosynthesis with accompanying lab.

Lesson 4.3

Students will be introduced to the light and dark reactions of photosynthesis, Cam plants and overall factors that affect the rate of photosynthesis with accompanying activities and worksheets.

Nested Structure 5

Conclusion of the photosynthesis unit and poster board presentations.

Lesson 5.1

Students work on their poster board presentations.

Lesson 5.2

Discussion: Why do we study photosynthesis? Students discuss the unique role and importance of photosynthetic organisms to all life. Each group will present their poster boards. Other groups will grade them based on the assessment table given to them.

Lesson 5.3

Students continue to present their poster boards defending them against their peers’ constructive criticism. Students will take a test on the content of the material and their understanding of scientific modeling.

Standards

Assessment Plan

The technique of embedded assessment is integrated in each lesson of this unit. This approach was selected because of its advantage in assessing student’s progress relative to understanding concepts, applying concepts, student’s performance skills, and providing feedback to all those concerned (teacher, parents, administrators, etc.) on student’s progress, over the entire unit. Furthermore, benefits such as matching what is taught and what is assessed, the matching of lesson objectives and the methods of student’s performance on these objectives was also achieved. Both aspects of informal and formal embedded assessment are employed in lessons and students are informed as to how and what they will be evaluated on. Assessment is conducted at the class, group and individual levels. Informal assessment such as frequent dialogue with students or by walking around the room and observing students as they build models or perform experiments allows for a teacher to monitor the students understanding. In addition, certain assignments are handed in and reviewed without a grade to assess student progress. Formal assessment is accomplished by having student's build and revise the alien model of the mechanism of photosynthesis. The alien model is handed in at the end of unit and is a culmination artifact designed to formally assess the accumulation of student’s understanding of concepts, inquiry and modeling techniques, and group interactions. A test administered at the end of the unit serves to assess concept understanding. Lab journals are handed in and graded.

The four variables and elements that we selected for our unit are as follows:

UNDERSTANDING CONCEPTS – It was important for us to assess student’s understanding of key concepts. We did not want to assess students by a multiple-choice test only because we felt this would fall short of our main goals. We wanted to discern with assurance that students not only understood scientific concepts (such as what is energy, what is good, how do food and energy relate? etc.) but were able to apply them to resolving problems. We also wanted to assess the teacher’s ability to scaffold students’ current knowledge and further develop this knowledge beyond their current conceptual knowledge. We therefore selected the following elements:

  • Recognizing Relevant Concepts – Assess whether the student was able to identify and recognize important enduring ideas presented in the unit.
  • Applying Relevant Concepts – Student’s need to draw ties to what they conceptually understand of underlying mechanisms and use these concepts to solve problems.

INQUIRY - Teaching science as inquiry provides teachers with the opportunity to develop student abilities relating to science and to enrich student understanding of science. Students performing inquiry activities are learning the essence of the nature of science i.e.; they are "doing science". The following elements were selected:

  • Performing investigations
  • Selecting and Recording Procedures
  • Organizing Data
  • Analyzing and Interpreting Data
  • Using Evidence - Students need to give priority to evidence, which allows them to develop and evaluate arguments and explanations. Evidence consists of observations and/or analysis of data collected. Student explanations should ultimately be consistent with currently accepted scientific knowledge.
  • Consider Solutions – Students need to demonstrate they considered all solutions and evaluated the best one based on evidence.

NATURE OF SCIENCE (NOS) - Understanding NOS is crucial to scientific literacy and needs to be incorporated into the curriculum. NOS are what and how scientists work and given this, NOS is embedded throughout our unit. Important elements of NOS we selected include the following:

  • Modeling - Students are provided the opportunity to engage in the scientific practice of model building. The process of modeling building requires refinements of the original working model after repeated experiments or discussions during the unit. The original working model evolves into a more complex one, which more closely matches the experimental results or concept of the mechanism of photosynthesis than the original version of the working model. Teaching science with modeling provides teachers with the opportunity to develop student abilities relating to science and to enrich student understanding of science. Students performing modeling activities are learning the essence of the nature of science i.e.; they are "doing science".
  • Scientific ideas are developed through reasoning. This addresses the knowledge and reasoning skills students must use to show proficiency in this unit.
  • The distinction between observation and inference. Observations are “directly” accessible to the senses (or extensions of the senses) and about which several observers can reach consensus with relative ease. Inferences are statements about phenomena that are not “directly” accessible to the senses. Student’s understanding of this will be assessed.
  • Students need to understand science is subject to peer review and replication. Peer review is an integral part of genuine scientific enterprise and is therefore an important element for assessment. The process of peer review includes examination of other student’s data and logic.
  • Students need to give priority to evidence, which allows them to develop and evaluate arguments and explanations. - Evidence consists of observations and/or analysis of data collected. Student explanations should ultimately be consistent with currently accepted scientific knowledge.

GROUP INTERACTION (GI) - A classroom is a community and in this community, students and teachers share responsibility for learning and collaborate on constructing understanding. Working in-groups helps to accomplish interdependence amongst students by having the group responsible for certain tasks and assignments. Elements selected for GI are as follows:

  • Time Management – Students need to show development of time management skills by working in a timely and efficient manner to get the job done.
  • Role Performance/Participation – Each and every student needs to show they participated at the class, group and individual levels.
  • Collaborative Process – Developing their skills to work as a team is extremely important.

The assessment blueprints designed for this unit follow.



Lesson 1.1&1.2

TITLE

Nature of energy as it relates to alien scenario.

OVERVIEW

This is the first lesson of the photosynthesis unit. It comprises two topics: introduction to the alien scenario and discussion of the nature of energy. At the end of this lesson students will create a list of possible alien energy sources. In the following lessons these concepts will be studied in details.

OBJECTIVES

Understanding Content:

  1. SWBAT define energy. (Ability to make something happen.)
  2. SWBAT understand the principle of energy conservation. (Energy cannot be created or destroyed. It can only change forms.)
  3. SWBAT identify and describe different types of energy and their conversion.
  4. SWBAT identify the difference between food and energy.
  5. SWBAT create a list of possible alien energy sources based on information provided.

Nature of Science:

  1. SWBAT understand what scientific models are and how they are used by scientists.

RELEVANT STUDENT PRECONCEPTIONS

ADDITIONAL SUPPORT FOR TEACHERS Addressing preconceptions is a critical part of every lesson. Previous knowledge can either help or hinder the understanding of new information. Before students can learn new concepts, they often must identify preconceptions that interfere with learning. “Teachers can help students change their original conceptions by helping students make their thinking visible so that misconceptions can be corrected and so that students can be encouraged to think beyond the specific problem or to think about variations on the problem.” (Bransford, 1999)

The clinical interviews conducted by our group reviled following preconceptions:

  1. Energy is a “thing.” Students interviewed would identify tangible things as energy. They would include in this category water, CO2 and nutrients. It is difficult to imagine an “amount” of an abstraction.
  2. The terms “energy” and “force” are interchangeable.
  3. The terms “energy” and “food” are interchangeable. This concept is very relevant to our alien scenario. Students should be trying to find out how Qs obtain energy. Not what they eat.
  4. Things “use up” energy. This concept stems from everyday observations. Such as car running out of fuel or batteries running out of power.
  5. Energy is truly lost in many energy transformations. The concept of energy conservation was very difficult for students to understand. Once again, they equated fuel with energy. Not its source.
  6. Energy is confined to some particular origin, such as what we get from food or what the electric company sells.

STANDARDS FOR NJ

  • STANDARD 5.5(Characteristics of Life) All students will gain an understanding of the structure, characteristics, and basic needs of organisms and will investigate the diversity of life. A. Matter, Energy, and Organization in Living Systems.(Covered in the subsequent lessons)
    • Explain how plants convert light energy to chemical energy.
    • Describe how plants produce substances high in energy content that become the primary source of energy for life.
  • STANDARD 5.7(Physics) All students will gain an understanding of natural laws as they apply to motion, forces, and energy transformations. B. Energy Transformations
    • Explain how the various forms of energy (heat, electricity, sound, light) move through materials and identify the factors that affect that movement.
    • Explain that while energy can be transformed from one form to another, the total energy of a closed system is constant.

MATERIALS AND PREPARATION

Time:

This lesson will take two periods (40 minutes each)

Materials:

Handouts:

  • Lesson 1.1- Handout 1. “Scenario”
  • Lesson 1.1- Handout 2. “Energy Quiz”
  • Lesson 1.2- Handout 3. “Energy Description”
  • Lesson 1.2- Handout 4. “Models in Science”
  • Lesson 1.2- Handout 5. “ Scientific Model”

Teacher’s references:

  • Reference 1. “Definition of Energy”
  • Reference 2. “Food vs. Energy”
  • Reference 3. “Answers to Energy Quiz”

ACTIVITIES

Lesson 1.1

1.Divide class in groups of five.

2.Ask students to solve following riddle:

What is this stuff?

Whatever happens is caused by it. Whatever is, is made up of it. You need it. You are made of it. Everything needs it. Everything is it. It is everything! You need it to run, to walk, to sit, to think, to sleep, "perchance to dream", to eat, "perchance to belch", or to make any other rude noises you shouldn't make. You use it constantly, every moment, awake or asleep. You can't get mad without it. You can't get glad without it. You can't get anything without it. It makes the wind blow, rain fall, and lightning zap and thunder. It "feeds" volcanoes and earthquakes. It drives tidal waves, typhoons, and tornadoes. It powers the universe. It powers bacteria. It is the Mysterious Everything. The Mysterious Everything keeps moving and changing. It exists in many forms. Over and over again it is transformed from one form to another. As far as anyone knows it never goes away, gets less, or gets more. The total amount always stays the same. It does not have to be done in groups. At this point general discussion would work really well. Once students guess the right answer (Energy), you could explain how it fits in the riddle and how truly important the energy is. “Nothing can happen without it.”

3.Present students with the alien scenario and information packet. Each student gets their own folder (handout for Lesson 1.1 pg 1-3). Ask them to read the information about aliens.

4.Ask students why would it be important for them to discover how Qs obtain their energy (what they eat)? The purpose of this question is to connect the concept of energy and Qs. It is supposed to engender interest and “need to know” in the nature of energy. Students prepare their answers in groups and have one of them present it to the rest of the class.

5.Ask each student to answer questions in the handout 2. Collect surveys for future reference. Tell students you will discuss answers at a later time. (You will discuss this survey at the end of this lesson, after the lecture on energy) This survey assesses students’ preconceptions about energy.

6.Ask students to define energy. They should come up with the answers in groups. Tell them to write their answers on a sheet of paper and hand it in at the end of the class. They can use the energy riddle as their clue. Each group will have one person present their definition of energy. (Make sure students within group alternate in answering questions.) These definitions do not have to be completely correct at this point. Students will have a lecture on what energy is and will be able to edit their perception of energy.

Lesson 1.2

1.Discuss what energy is. Use definitions each group handed in at the end of the last lesson and surveys of students’ preconceptions about energy to emphasize harder to understand concepts. (You can use teacher reference number 1.)

2.Ask students to complete handout #3. Students should work in groups. During the activity, observe student contribution and analysis of ideas. Upon completion of the task one student from each group will present the answer and the rational for one of the pictures. Students in other groups should listen and add any comments they have. Each group presents the answer to different picture to avoid redundancy. This activity tests not only content understanding but its application as well. (Some of the pictures present few different types of energy. Make sure all are discussed.) This activity presents a great opportunity to address students’ preconceptions and important ideas about energy.

3.Ask students to take out their folders with handouts about the aliens. Ask them if it is possible for an organism to function without energy. Ask them if they think that energy and food are synonymous. Discuss the relation between energy and food. You can use teacher’s reference #2.

4.Tell students their assignment is to find out how Qs obtain energy. At this point you should discuss how scientists approach similar problems. Focus on data collection and analysis. Explain what modeling is as viewed by scientists. Give students handout 4 (“Models in Science”) as a reference. Tell them they will have to create a model of a process by which Qs obtain energy and present it in a form of presentation board. Presentation boards will be collected and graded at the end of this unit. In addition to handout 4 give students handout 5 (“Scientific Model”) so they fully understand what their models should accomplish.

DIFFERENTIATED INSTRUCTION

For the benefit of the lower achieving students multiple representations of data was used: written, graph and tables.

ASSESSMENT

This lesson provides opportunities for group assessment as well as individual one. Teacher observes group work observing student’s contribution and analysis of ideas. Moreover, when assignment is completed, each time different student presents group’s work; creating great opportunity for individual assessment. Through numerous discussions tasks assigned test not only the knowledge of the content but also its understanding.

HANDOUTS

Lesson 1.1 Handout 1. Scenario

You are a part of an interstellar research group. You are the lead scientists on board. Your team discovers an unknown planet in an uncharted territory. The aliens are very friendly and invite your crew to live among them. You decide it would be interesting to see how they live. The aliens call themselves Qs.(You can communicate with them using your universal translator).

They do not seem to eat anything and they do not seem to excrete anything. How curious!!! You are intrigued. What do they “eat”? Why do they look the way they do?

Being the scientists that you are, you decide to solve this mystery. Included is some initial information you collected about the planet and their inhabitants. Upon studying these findings your team’s assignment is to build a hypothetical model explaining the aliens’ energy source.

Inhabitants: Qs

Your new acquaintances have a unique appearance:

  • Many are green, but some are purple, red, or brown.
  • Their skin appears to have many pores.
  • Red and brown Qs tend to live in the water covered areas of the planet.
  • Red Qs like to float on the surface. The brown Qs stay deeper underneath the surface.
  • Qs living on the ground are either green or purple. They tend to drink enormous amounts of water all the time.
  • They also, unlike the red and brown Qs, have long extensions projecting from their bodies. They are often seen through out the day inserting these extensions into vats containing some colorless fluid for long periods of time.
  • All Qs love to sunbathe.
  • They sleep at night and are very lethargic during cloudy days.
  • They hibernate in the winter time.
  • They also grow more in the winter time.
  • Qs living in the equatorial region (warmest region on the planet) have thick, leathery skin. The holes in their skin are closed during the day and open during the cooler and more humid nighttime hours. Most of them are rather short. They do not grow as fast as Qs living in other regions of the planet.

Table 1

PlanetBajor
ShapeSphere
Mean radius8, 547.654 km
Equatorial circumference45,453.987 km
Surface area670,789,500 km^2
Volume1.334 456 x 10^12 km^3
Mass6.2345 x 10^24 kg
Day10 hrs
Night10 hrs
Year240 days
Covered by water75%
Terra firma25%
Equatordry,hot,noseasons
Northern hemispheretemperate,4 distinct seasons
Southern hemispherewarm, humid,4 distinct seasons

Table-2 Atmospheric Conditions

Planet Bajor Tested 1/05Tested 4/05Tested 8/05Tested 12/05
Gas (name)Chemical CompositionPercent VolumePercent VolumePercent VolumePercent Volume
NitrogenN278.08%78.08%78.08%78.08%
OxygenO220.95%20.95%21.34%21.02%
WaterH2O0 to 4%0 to 4%0 to 4%0 to 4%
ArgonAr.93%.93%.93%.93%
Carbon DioxideCO20.0360%0.0350%0.0280%0.0321%
NeonNe0.0018%0.0018%0.0018%0.0018%
HeliumHe0.0005%0.0005%0.0005%0.0005%
MethaneCH40.00017%0.00017%0.00017%0.00017%
HydrogenH20.00005%0.00005%0.00005%0.00005%
Nitrous OxideN200.00003%0.00003%0.00003%0.00003%
OzoneO30.0000004%0.0000004%0.0000004%0.0000004%


Lesson 1.1 Handout 2. Energy Quiz

Name: Date:

Read ten statements below. Each relates information about energy. Some of the statements are based on common preconceptions and some are true. After each statement, circle the T if you feel that the statement is in fact true and circle the F is you feel the statement is false. Be prepared to express the reasoning behind your opinion.

  1. Energy is found only in living things. T F
  2. Electric current is a flow of energy. T F
  3. Energy is associated only with movement. T F
  4. Energy is created as the result of an activity. T F
  5. Energy can be recycled through an ecosystem many times. T F
  6. Energy is a fuel. T F
  7. Energy is a force. T F
  8. Energy is stored within objects. T F
  9. Energy is a substance or fluid. T F

Lesson 1.2 Handout 3. Energy Description

Names:

In your group write down next to each picture why the phenomenon depicted is a representation of energy. Some of the pictures may depict more than one type of energy. Make sure you address all of them.

Ice cube
Storm
Tornado
Dancing
Worker
Old

Lesson 1.2 Handout 4. Models in Science

Most children like to play with models, including model cars, tinker toys, model houses, and so on. Likewise, most scientists interact with models. However, their model interaction is out of necessity, as the forging of new science is frequently dependent on the development of models. When you think about it, it is easy to understand the importance of models in science. Many times the objects of a scientist’s attention are too small to be observed directly, or they may be inaccessible for direct visual study, as would be the case for the center of the Earth or the surface of a distant galactic object. Other topics of study, such as gravity, magnetism, or energy, can be studied through their effects on matter. But gravity, magnetism, and energy cannot be seen directly, so they too are modeled. You may think of additional reasons why it would be necessary for scientists to develop models as they probe the secrets of nature.

Types of Models

The models that scientists develop take many different forms. In some cases they are actual physical constructions. A good example of this kind of model would be one that represents the Earth, moon, and sun as small wooden spheres that are mechanically moved in such a way as to illustrate the phases of the moon, eclipses, and so forth (see Figure 1).
Figure1
Other models may be nothing more than mental images that are developed in an effort to picture something unseen. A good example would be the Bohr solar system model of the atom that is often used by beginning chemistry students. In this model the nucleus is imagined to be like the sun and the electrons are visualized as whirling around the nucleus analogous to the planets orbiting the sun (see Figure 2).
Figure 2

Other models are mathematical in nature and depend on algebraic or other kinds of statements to describe a phenomenon or object. Models usually evolve and are improved as scientific advances are made. Not infrequently, a model is thrown out completely based on new findings that prove it to be misleading or fatally incorrect. It is also the case that different models often are used to describe the same thing, and the choice of models depends on the goal of the scientific investigation or perhaps the scientific sophistication of the individual conducting the work. A good example once again is models of the atom. The solar system model is adequate for many purposes, but a highly mathematical model based on the field of quantum mechanics is necessary for rationalizing other aspects of an atom’s behavior. In a fundamental way, models are developed in an effort to explain how things work in nature.

Model Development and Use

So how are models developed? Basically they are conceived by making physical observations on a system of interest to establish facts. Scientists then combine these facts with appropriate laws or scientific principles and assumptions to give a “picture” that mimics the behavior of the system to the greatest possible extent. It is on the basis of such models that science makes many of its most important advances, because such models provide a vehicle for making predictions about the behavior of a system. These predictions can be tested later as new measurements, technology, or theory are brought to bear on the subject. The new measurements may result in modification and refinement of the model, although certain issues may remain unresolved by the model for years. Nevertheless, the goal always is to continue to develop the model in such a way as to move it ever closer to a true description of a natural phenomenon. It has been necessary to model objects in the solar system. Recent history has changed this to a certain degree, since missions have been sent to the moon and Mars that provide opportunity for direct visual inspection of, at least, part of the surface of these neighbors. Clearly these missions, along with others, have changed and improved the existing models of the moon, Mars, and other objects in the solar system. This is the nature of science.


Lesson 1.2 Handout 5. “Scientific Model”

A scientific model is an idea or set of ideas that explains what causes a particular phenomenon in nature. To do this, scientists make observations, identify patterns in data, then develop and test explanations for those patterns. Scientists use drawings, graphs, equations, three dimensional structures, or words to communicate their models (which are ideas and not physical objects) to others. However, the drawings, replicas or other tools are distinct from the underlying models they help to explain. To evaluate a particular model, scientists ask:

  1. Can the model explain all the observations?
  2. Can the model be used to predict the behavior of the system if it is manipulated in a specific way?
  3. Is the model consistent with other ideas we have about how the world works and with other models in science?

Moreover, more than one model may be an acceptable explanation for the same phenomenon. It is not always possible to exclude all but one model – and also not always desirable. For example, physicists think about light as being wavelike or particle-like and each model of light’s behavior is used to think about and account for phenomena differently. A “good” scientific model is…

  • based on observations,
  • able to explain as many characteristics of observations as possible,
  • as simple as possible,
  • able to explain phenomena that are seemingly different from the ones we used to develop the model in the first place,
  • testable.

All models have limitations — no model can possibly explain every detail of a scientific phenomena.


Teacher’s references. Reference 1. Definition of energy:

All the school books say energy is the ability to do work. But what does that mean? Well it sort of means the ability to make something happen. Every time a force is exerted on something through a distance (which is the definition of work) something had to move, which means something happened. Energy can be transferred through heat flow, like when you put a pot of water on the stove and the water gets hotter. Something happened for sure. Something changed. The water got hot and eventually, if left on the hot stove long enough, will start to boil. Energy is a property or characteristic (or trait or aspect?) of matter that makes things happen, or, in the case of stored or potential energy, has the "potential" to make things happen. By "happen", we mean to make things move or change condition. Examples of changes in condition are changes in shape, volume, and chemical composition (results of a chemical reaction). There are also changes in pressure, temperature, and density which we call a "change of state" in thermodynamics. Phase changes, such as changing from solid to liquid, or liquid to vapor, or back the other way, are also good examples of condition changes. Something happened! Without energy, nothing would ever change, nothing would ever happen. You might say energy is the ultimate agent of change, the mother of all change agents. Whenever anything happens or changes there is an energy change. Either energy changes form, as when a generator changes mechanical energy into electrical energy; or energy changes location, as when heat flowing too fast out of your body makes you cold, or heat flowing into a pot of water makes the water turn into steam. You get the idea.

Reference 2.

Food: organic compounds with high-energy molecular bonds that organisms can use for growth and metabolism; energy supplying substances. Food is not whatever plants or animals take in to keep alive and growing. There is a distinction between energy-containing and non-energy-containing matter. Energy: Capacity to do work. The most important concept is that energy can change form.

Reference 3.

Answers to Energy Preconceptions True-False Quiz

  1. Energy is found only in living things. FALSE: This statement is not correct because everything has energy. In physics, energy is defined as the ability or capacity to do work or to produce change. Forms of energy include heat, light, sound, electricity, and chemical energy. The composition of an object or its position determines what kind of energy it has (e.g., chemical, potential, thermal). Living things are unique because they have the ability to convert energy in the food they consume to another form.
  2. Electric current is a flow of energy. FALSE: Electric current is actually the very slow flow of charged particles. On the other hand, electric energy is different in that it moves very rapidly. Electric energy moves at a different speed than electric current; so there must be two different things flowing in wires at the same time. In an electric circuit, the path of the charges is circular. The path of the energy is not. A battery can send electric energy to a light bulb, and the bulb changes electrical energy into light. The energy does not flow back to the battery again. At the same time, the electric current is a circular flow, and the charges flow through the light bulb filament and return to the battery. Electric energy can even flow in a direction opposite to that of the electric current. In a single wire, electric energy can move continuously forward while the direction of the electric current is alternating back and forth at high frequency.
  3. Energy is associated only with movement. FALSE: Nonmoving objects have potential energy. The composition of an object or its position determines what kind of energy it has (e.g., chemical, potential, thermal). A moving object has kinetic energy.
  4. Energy is created as the result of an activity. FALSE: As the result of an activity or process, energy is transferred from one system to another. Examples include generating electricity and eating food. No additional energy is created during an activity. If this were the case, energy would be created from nothing—and that is impossible! The first law of thermodynamics, often called the law of conservation of energy, states that energy can be transferred from one system to another in many forms. However, it cannot be created or destroyed. Thus, the total amount of energy available in the universe is constant. Einstein’s famous equation E = MC2 describes the relationship between energy and matter. Energy (E) is equal to matter (M) times the square of a constant (C). Einstein suggested (by way of his equation) that the quantity of energy and matter in the universe is fixed.
  5. Energy can be recycled through an ecosystem many times. FALSE: Energy “flows” through an ecosystem in the form of carbon-carbon bonds. When respiration occurs, the carbon-carbon bonds are broken and the carbon is combined with oxygen to form carbon dioxide. This process releases the energy, which is either used by the organism (to move its muscles, digest food, think, and so on) or lost as heat. Most of the energy in an ecosystem comes from the Sun. The ultimate fate of all energy in all ecosystems is to be lost as heat. Energy does not recycle!! The field of thermodynamics studies the behavior of energy flow in natural systems. It is the second law of thermodynamics that deals with the fact that energy cannot be cycled through an ecosystem in the same way that matter is. It deals with the fact that heat can never pass from a colder to a hotter object. Natural processes that involve energy transfer must have one direction, and all natural processes are irreversible. This law also predicts that the entropy of an isolated system increases over time. Entropy is the measure of the disorder or randomness of energy and matter in a system. Because of the second law of thermodynamics, both energy and matter in the universe are becoming less useful as time goes on.
  6. Energy is a fuel. FALSE: Fuel is a source of energy but is not itself energy. Fuel is a resource such as coal, oil, and the food we eat. Fuels have potential energy in the chemical bonds that make up the substance. Fuel is defined as something that is burned to provide power or heat. It could also be fissionable material used to create power in a nuclear generator.
  7. Energy is a force. FALSE: A force is a push or a pull. Energy is needed to create the force, but it is not the force. A force, through movement, changes the state of energy in an object (e.g., from potential to kinetic energy).
  8. Energy is stored within objects. FALSE: This statement might lead to the understanding that energy is a substance. There is potential energy in the chemical bonds of objects or because of its position (e.g., gravity), but the object itself does not contain energy.
  9. Energy is a substance or fluid. FALSE: Energy is a state; it is not matter (i.e., it does not contain molecules). For example, steam, liquid water, and ice are all the same substance (contain the same molecular structure), but because of their different states of energy, they appear different.

[cat:dtse2007]

Lesson 2.1

TITLE

Alien Energy Sources

OVERVIEW

In the previous lesson, the students discussed what energy is, and the relationship between food and energy. Now the students need to figure out how the aliens are obtaining their energy. The students will begin to work out some of the possible sources of energy for the aliens. What do they think they are using for food? How? What is going into or coming out of the aliens? The students should mention sunlight, water, co2, o2 and possibly many others. Focus today’s discussion on co2, water and the vat of nutrients. The students will begin filling out the chart, worksheet 2.1A. The chart is being used to guide them towards developing their own hypothesis. The students will also start developing their models. They need to analyze each input or output they come up with and follow up with the questions on worksheet 2.2A. The student’s will split up into their lab groups for this activity. In the next lesson, the students will focus on the data on light and oxygen. They will complete the chart and their models of how Q’s obtain energy.

OBJECTIVES

The learning objectives for this lesson are:

Understanding content:

  • Students will be able to explain what energy is as it relates to organism.
  • Students will be able to explain that food is different from energy.

Nature of Science:

  • Students will practice developing scientific knowledge, hypotheses and models based on observations of the natural alien world.
  • Students will understand that scientific knowledge is subjective and subject to change.

Inquiry:

  • Students will examine observations of aliens and develop models of how they think the aliens obtain energy.
  • Students will design a simple experiment to test an observation of the alien scenario.

RELEVANT PRECONCEPTIONS

The concept of energy and the relationship between energy and food was the most difficult for students. Energy was described vaguely or in a physical way such as movement or force. They did not express the conversion of energy from light to chemical. Students expressed that things need energy but in the way that they need water, and nutrients. It all just helped things “grow. Inputs such as food/sun/water were described as what gave organisms energy not that organisms used these things to make glucose to make ATP which is the source of energy for the organism.


CURRICULUM STANDARDS

  • New Jersey Standard 5.1- All students will develop problems solving, decision making and inquiry skills, reflected by formulating usable questions and hypotheses, planning experiments, conducting systematic observation, interpreting and analyzing data, drawing conclusions and communicating results.
  • New Jersey Standard 5.5- All students will gain an understanding of the structure, characteristics and basic needs of organisms and will investigate the diversity of life.

MATERIALS AND PREPARATION

Time: One to two class periods. This will depend on their grasp of what energy is and how they work through the data to find possible sources of energy for the aliens. You can use sheet 2A to assist your review/discussion of the scientific process and coming up with a hypothesis statement.

Materials: Need transparencies: Worksheet 2.1 for explanation, Sheet 2B-model example and characteristics and Worksheets 2.1 and 2.2 and 2.3.-handouts

ACTIVITIES

  1. You should begin class with a question and answer session to refresh their thinking and cue them to look for what the aliens may be using for energy from the data. So what is energy? Is food energy? Where do various organisms get their energy? How do organisms use energy? Try to pull out two ideas: that food is used as a source material and food is used to get energy.
  2. Ask the students what they think is going into the organism and what is coming out? What are the inputs and outputs?
  3. Write down their responses on the board. You want them to name all the basic elements that are in their environment from the data. You are looking specifically for them to say CO2, O2, water, vat of liquid/nutrients, light. They may say many more such as air but you can say ask them to look at the atmospheric table which would show the air comprises both gases. Keep the students on task by looking at the data.
  4. Their task is to come up with a hypothesis as to how the aliens get their energy and begin working on their models. Their models can be drawn, written as an equation, flow chart etc.
  5. Now you will show them the chart on the overhead. Explain how the chart is to be filled out. Today you will focus on the data for CO2, water, and nutrients. The students need to look at all the data focusing on these three elements and complete the chart for these elements and answer the questions on worksheet 2.2.
  6. Show the transparencies for modeling and building a hypothesis and briefly review these concepts to help them with their task.
  7. At this point, have the kids get into their lab groups, ideally 3-4, to work on the chart, the questions and developing their models. Students will use 2.3 worksheet throughout the unit to write down any changes they want to make to their model


DIFFERENTIATED INSTRUCTION

Heterogeneous groups will be organized and collaboration is encouraged for the chart and worksheet 2.2. Also an exemplary model will be explained in written form and in pictorial form.

ASSESSMENT

Most of the lesson is discussion and individual student work. Students will be assessed on their group interaction and participation. The student’s worksheet responses will be assessed for their understanding of how to design an experiment, their ability to analyze and interpret data, and applying their understanding of energy acquisition to a new organism.

Lesson 2.1-2A The Scientific Process

  1. All scientific knowledge is from observational data.
  2. Scientific theories are systematic predictions that are logical and consistent based on observations and experiments.
  3. A hypothesis is a working assumption- your job is to see if it “holds” against the available data. You need to stay consistent and double check your evidence.
  4. A hypothesis is a limited statement regarding cause and effect in specific situations. It is limited because it is stated before an experiment is done to test the validity of your statement. To take an example from daily life, suppose you discover that your car will not start. You may say, "My car does not start because the battery is low." This is your first hypothesis. You may then check whether the lights were left on, or if the engine makes a particular sound when you turn the ignition key. You might actually check the voltage across the terminals of the battery. If you discover that the battery is not low, you might attempt another hypothesis ("The starter is broken"; "This is really not my car.")
  5. Science can be subjective-(ask the students what does subjective mean?) or influenced by bias or prejudice or preconceived notions or beliefs.
  6. Science is always subject to change.
  7. Albert Einstein said, “No amount of experimentation can ever prove me right. A single experiment can prove me wrong”.


Lesson 2.1/2B The Scientific Process-Models


A model is an idea. It provides the framework for the hypothesis. It can be presented as a drawing, a graph, a flow chart, an equation, a sculpture or any other form of expression. The criteria for your models are:

  1. BASED ON YOUR OBSERVATIONS OF THE DATA
  2. ACCOUNTS FOR THE EVIDENCE
  3. EXPLANATORY-SHOWS THE MECHANISM-HOW THE ALIENS ARE GETTING THEIR ENERGY
  4. CLEAR AND COMMUNICATIVE
  5. CLEARLY LABELED


Examples of Different Models





















Lesson 2.1/Worksheet 2.1 Name: ______________ Date:________________

Alien Energy Analysis Chart Elements For Energy For Growth and survival For both Notes/ Evidence


Lesson 2.1/ Worksheet 2.2 Name: _______________ Date:_________________

Alien Energy Hypothesis Worksheet


At this point, you should be developing your idea as to how the aliens are getting their energy. To help you work your way through this scientific process, please answer the following questions as best you can.


What element/input do you feel is most important to the aliens energy needs? Why?


What element/input do you feel is the least important to the aliens energy needs? Why?


Pick one data point or observation. Is it testable? How could you test for this? Design a simple experiment to test your observation. (Make sure you have a control and an experimental group)




With what you know up to this point, what is your hypothesis for how the aliens are obtaining their energy?

Hypothesis Statement:


Evidence:




Work on a model of your hypothesis on the worksheet below.


Lesson 2.1/Worksheet 2.3 Name: ________________ Date: _________________

Model in progress……….

Lesson 2.2

Are Light, Gases or Glucose Energy?


OVERVIEW


In the previous lessons, the students were asked an open-ended driving question: How are the aliens obtaining energy? Students will continue their investigation into the possible sources of energy for the aliens. In this lesson, students are to continue their investigation with additional handout material to be given to the students on the Q aliens that were recently discovered by researchers. This additional material along with the previous packet of information will help students in their investigation of whether light, gases (Oxygen) and/or glucose are the sources of energy for the aliens. This will requires students to actively investigate in depth the new information along with the previous packet of information and synthesize all previous and new sources of information.

Students will have to carry out experiments and communicate their results. They will make predictions and communicate and argue their proposed model designs. From this they will need to revise their initial models in light of the anomalous data and in response to critiques of others.


OBJECTIVES


Inquiry and Nature of Science:


  1. SWBAT apply prior knowledge current problems; pose inquisitive questions and generate data.
  2. SWBAT perform critical analysis of information provided and gather data.
  3. SWBAT communicate and argue their proposed model designs
  4. SWBAT revise initial models in light of anomalous data and in response to critiques of others.
  5. SWBAT analyze the role of oxygen, light and glucose as possible sources of energy in the alien scenario.


RELEVANT STUDENT PRECONCEPTIONS


In the conducted student interviews, it was ascertained that only six out of twelve students knew that glucose is the end product produced in photosynthesis. The products and reactants were not clear and therefore they could not expand on what would affect the rate of the plant's production. Most of them understood there was a process and a change involved but couldn’t explain it fully.


CURRICULUM STANDARDS


  • New Jersey Standard 5.1- All students will develop problems solving, decision making and inquiry skills, reflected by formulating usable questions and hypotheses, planning experiments, conducting systematic observation, interpreting and analyzing data, drawing conclusions and communicating results.
  • New Jersey Standard 5.5- All students will gain an understanding of the structure, characteristics and basic needs of organisms and will investigate the diversity of life.


MATERIALS AND PREPARATION


  • Time:
  • Two 40-minute periods.
  • Prepare with a reflection on Lesson 1.1, 1.2 and 2.1
  • See Lab Experiments
  • Materials:
  • Handout 1,2,3,4,5,6


NOTES TO THE TEACHER


This lesson is very hands on with three lab experiments. Please review all materials and procedures before start of activities.


ACTIVITIES


ACTIVITY 1


Recap: Remind students of what they learned from previous lesson 2.1. Distribute the following handout to each student to recap yesterday’s lesson. (Note to teacher: this relates to NOS objective). Review Food and Energy Supplement. Have a small discussion on what food and energy is. Once you have distributed handouts read the following statement along with the students:


"We will continue to answer ““How do Aliens obtain their energy?”” You will be responsible for studying this problem in your original group of two, reviewing new sources of information on the aliens and revising your models/solutions and presenting your new solutions to your classmate.


This class is all about making sense out of what we know and what still remains to be answered. This requires you to continually review new data, incorporate the new data into your answer, and question each other’s understanding in a constructive way. It will require you to justify statements that you make and question the statements of others" The purpose of this is to help you understand how biologists work in the real world to address questions posed to them to solve because this is similar to how they pursue problems.”


ACTIVITY 2


For the rest of the lesson, the students will work in pairs. The teacher should then begin to generate interest in today’s assignment by stating the following:


“Today we are going to explore the bubbles that are believed to be released from the aliens. Can these bubbles have something to do with the energy of aliens? Additionally we will investigate new information provided on the aliens from another science team that was just released in the news that may provide some clues to help us in our search. But first, we will start off investigating the mysterious bubbles.”

The information below will be given to each pair to complete throughout the lesson.

Here is an actual lab you and your lab partner will conduct together. You will be able to see if all of the specimens of aliens release bubbles when exposed to light. Record everything in your individual lab journals.


MATERIALS REQUIRED:

  • 5 Test Tubes
  • Erlenmeyer flask
  • Tap Water (cold)
  • Sharpie Pen to label test tubes
  • Sodium Bicarbonate Solution (baking soda and water)
  • 4 Sample Specimens (1 Red, 3 Green)
  • Lamp with 200 watt bulb
  • Meter Stick
  • Stopwatch
  • Test Tube Rack
  • Ruler
  • Razor cleaned with alcohol to cut specimens


TECHNIQUE:


  1. Remove a small piece of the skin from the red alien specimen by cutting piece off a small piece (8 cm x 8 cm) to test tube.
  2. Immediately add enough NaHCO3 solution to the test tube to cover the sample entirely.
  3. Label Test tube as Specimen 1.
  4. Place all the test tube with the sample in an Erlenmeyer flask containing enough cool tap water to cover most of the tube. Place the flask in 0.5m from the lamp. Let the setup sit for 5 minutes to equilibrate to the light conditions. After about 5 minutes observe the specimen.
  5. Count the number of bubbles forming.
  6. Record your data in table the table below.
  7. Repeat Counting after 1 minute for four more time
  8. Remove a small piece of the skin from the red alien specimen by cutting piece off a small piece (8 cm x 8 cm) to test tube.
  9. Immediately add enough NaHCO3 solution to the test tube to cover the sample entirely.
  10. Label Test tube as Specimen 2.
  11. Place all the test tube with the sample in an Erlenmeyer flask containing enough cool tap water to cover most of the tube. Place the flask in a dark place. Let the setup sit for 5 minutes to equilibrate to the light conditions. After about 5 minutes observe the specimen.
  12. Count the number of bubbles forming.
  13. Record your data in table the table below.
  14. Repeat Counting after 1 minute for four more time
DATA TABLE 1: Group Data
Count of the Number of Bubbles
Time Minute 1 Minute 2 Minute 3 Minute 4 Minute 5
Specimen 1 With light
Specimen 2 Without light

15. What is the purpose of placing the skin specimen in a NaHCO3 solution? Write your explanation below:

The answer is acts like CO2

16. Examine Your Results? Write your explanation of the results below:


ACTIVITY 3


Here is an actual lab you and your lab partner will conduct together to determine the constituents of the bubbles? Since we know the aliens planet atmosphere is comparable to Earth’s lets start off our investigation of the gases in Earth’s Atmosphere as possible suspects of what the gas may be.


MATERIALS


  • Computer
  • Vernier computer interface
  • Logger Pro
  • Vernier Methane Gas Sensor
  • Vernier CO2 Gas Sensor
  • Vernier Nitrogen Gas Sensor
  • Vernier O2 Gas Sensor
  • 10 mL graduated cylinder test tube rack
  • 250 mL Nalgene bottle thermometer
  1. Remove a small piece of the skin from the green alien specimen by cutting piece off a small piece (8 cm x 8 cm) to test tube.
  2. Place the contents of the test tube into a clean 250 mL Nalgene bottle. Repeat this Section in total for each of the gas sensors identified in the materials section. Replace the word Oxygen with Methane and do steps 5 to 11. Replace the word Oxygen with CO2 and do steps 5 to 11. Replace the word Oxygen with Nitro gen and do steps 5 to 11.
  3. Use a computer and an Nitrogen sensor to measure the production of nitrogen gas
  4. Connect the Nitrogen Gas Sensor to the computer interface. Prepare the computer for data collection by opening the file “06A Enzyme (Nitrogen)” from the Biology with Computers folder of Logger Pro.
  5. Place the Nitrogen Gas Sensor into the bottle as shown in Figure 1. Gently push the sensor down into the bottle until it stops. The sensor is designed to seal the bottle without the need for unnecessary force.
  6. When 30 seconds has passed, Click to begin data collection.
  7. When data collection has finished, remove the Nitrogen gas sensor from the Nalgene bottle. Rinse the bottle with water and dry with a paper towel.

Figure 1

  1. Move your data to a stored run. To do this, choose Store Latest Run from the Experiment menu.
  2. Create a graph of the Nitrogen gas. Plot the values for the Nitrogen on the y-axis, and the time on the x-axis.
  3. Examine Your Results? Write your explanation of the results below:


BREAK POINT


ACTIVITY 4

New information has just been discovered about the aliens. The aliens’ skin is reported to taste sweet. One of the researchers accidentally placed one of the specimen samples in his mouth. We need to investigate what the skin contains that would make it sweet? Record everything in your individual lab journals.


Testing Specimens for Starch/Sugar (Activity)


Material Required


  1. 1 Test Tube #50 ml Water (boiling)
  2. Erlenmeyer flask #White piece of paper towel
  3. 50 ml Tap Water (cold) # Sharpie Pen to label test tubes
  4. 1 Sample Specimens (1Green) # Razor cleaned with alcohol to cut specimens
  5. forceps (tweezers) # Iodine solution. (Tincture of iodine)
  6. 25ml alcohol (rubbing alcohol) # Test Tube Rack
  7. Dropper


REMEMBER TO ALWAYS WEAR SAFETY GLASSES

CARE! CARE! CARE! The alcohol must not be close to a flame, so you must boil the water first. Turn off your heating appliance, and then put the test tube into the beaker of boiling water.

  1. Place water in beaker and boil
  2. Remove a small piece of the skin from the green alien specimen by cutting piece off a small piece (10 cm x 10 cm). Hold the specimen with forceps (tweezers) and dip it into a beaker of boiling water for about 30 seconds. This prevents any further reactions from occurring in the specimen.
  3. The second step is to put the specimen into a test-tube containing about 25ml of alcohol (rubbing alcohol is fine). Now place the test tube into a beaker of boiling water.
  4. Step three involves watching and waiting for the specimens green color to be removed. The alcohol will turn green. The more color you can remove from the specimen the better.
  5. Step four requires you to remove your specimen from the alcohol and to wash it in cold water to remove the alcohol.
  6. Now you are ready for step five. Spread your washed specimen on a clean, white surface (a clear plastic dish with a white piece of paper). Using a dropper, COVER the specimen with Iodine solution. (Tincture of iodine that you can buy at the drug store is fine.)


CARE! CARE! CARE! Iodine solution should not be inhaled. If it gets in the eyes, it should be washed out immediately and professional advice should be sought. If your specimen contains starch, then the golden-brown iodine solution will become black in color.


ACTIVITY 5


Review all results from this lesson. How might you change the model you have been working on to determine the energy source of the aliens? Revise your model accordingly to reflect all the new information you obtained.

How does today’s activity relate to how scientists work in the real world? Write your thoughts below:


CONCEPTS

Review Food and Energy Supplement. Have a small discussion on what food and energy is.


SUPPLEMENTARY MATERIALS


Handout on Food and Energy from Lesson 1.1 Lesson 2.2 Handout 1.


"We will continue to answer ““How do Aliens obtain their energy?”” You will be responsible for studying this problem in your original group of two, reviewing new sources of information on the aliens and revising your models/solutions and presenting your new solutions to your classmate.

This class is all about making sense out of what we know and what still remains to be answered. This requires you to continually review new data, incorporate the new data into your answer, and question each other’s understanding in a constructive way. It will require you to justify statements that you make and question the statements of others" The purpose of this is to help you understand how biologists work in the real world to address questions posed to them to solve because this is similar to how they pursue problems.”


Lesson 2.2 Handout 2.1 ACTIVITY 1

Recap: Remind students of what they learned from previous lesson 2.1. Distribute the following handout to each student to recap yesterday’s lesson. (Note to teacher: this relates to NOS objective). Review Food and Energy Supplement. Have a small discussion on what food and energy is. Once you have distributed handouts read the following statement along with the students:

"We will continue to answer ““How do Aliens obtain their energy?”” You will be responsible for studying this problem in your original group of two, reviewing new sources of information on the aliens and revising your models/solutions and presenting your new solutions to your classmate.

This class is all about making sense out of what we know and what still remains to be answered. This requires you to continually review new data, incorporate the new data into your answer, and question each other’s understanding in a constructive way. It will require you to justify statements that you make and question the statements of others" The purpose of this is to help you understand how biologists work in the real world to address questions posed to them to solve because this is similar to how they pursue problems.”


Lesson 2.2 Handout 3. ACTIVITY 2

For the rest of the lesson, the students will work in pairs. The teacher should then begin to generate interest in today’s assignment by stating the following:


“Today we are going to explore the bubbles that are believed to be released from the aliens. Can these bubbles have something to do with the energy of aliens? Additionally we will investigate new information provided on the aliens from another science team that was just released in the news that may provide some clues to help us in our search. But first, we will start off investigating the mysterious bubbles.” The information below will be given to each pair to complete throughout the lesson.

Here is an actual lab you and your lab partner will conduct together. You will be able to see if all of the specimens of aliens release bubbles when exposed to light. Record everything in your individual lab journals.


Material Required

  1. 1 Test Tube #50 ml Water (boiling)
  2. Erlenmeyer flask #White piece of paper towel
  3. 50 ml Tap Water (cold) # Sharpie Pen to label test tubes
  4. 1 Sample Specimens (1Green) # Razor cleaned with alcohol to cut specimens
  5. forceps (tweezers) # Iodine solution. (Tincture of iodine)
  6. 25ml alcohol (rubbing alcohol) # Test Tube Rack
  7. Dropper


TECHNIQUE:


  1. Remove a small piece of the skin from the red alien specimen by cutting piece off a small piece (8 cm x 8 cm) to test tube.
  2. Immediately add enough NaHCO3 solution to the test tube to cover the sample entirely.
  3. Label Test tube as Specimen 1.
  4. Place all the test tube with the sample in an Erlenmeyer flask containing enough cool tap water to cover most of the tube. Place the flask in 0.5m from the lamp. Let the setup sit for 5 minutes to equilibrate to the light conditions. After about 5 minutes observe the specimen.
  5. Count the number of bubbles forming.
  6. Record your data in table the table below.
  7. Repeat Counting after 1 minute for four more time
  8. Remove a small piece of the skin from the red alien specimen by cutting piece off a small piece (8 cm x 8 cm) to test tube.
  9. Immediately add enough NaHCO3 solution to the test tube to cover the sample entirely.
  10. Label Test tube as Specimen 2.
  11. Place all the test tube with the sample in an Erlenmeyer flask containing enough cool tap water to cover most of the tube. Place the flask in a dark place. Let the setup sit for 5 minutes to equilibrate to the light conditions. After about 5 minutes observe the specimen.
  12. Count the number of bubbles forming.
  13. Record your data in table the table below.
  14. Repeat Counting after 1 minute for four more time
DATA TABLE 1: Group Data
Count of the Number of Bubbles
Time Minute 1 Minute 2 Minute 3 Minute 4 Minute 5
Specimen 1 With light
Specimen 2 Without light

What is the purpose of placing the skin specimen in a NaHCO3 solution? Write your explanation below: The answer is acts like CO2


Examine Your Results? Write your explanation of the results below:


Lesson 2.2 Handout 4. ACTIVITY 3


Here is an actual lab you and your lab partner will conduct together to determine the constituents of the bubbles? Since we know the aliens planet atmosphere is comparable to Earth’s lets start off our investigation of the gases in Earth’s Atmosphere as possible suspects of what the gas may be.


MATERIALS


  • Computer
  • Vernier computer interface
  • Logger Pro
  • Vernier Methane Gas Sensor
  • Vernier CO2 Gas Sensor
  • Vernier Nitrogen Gas Sensor
  • Vernier O2 Gas Sensor
  • 10 mL graduated cylinder test tube rack
  • 250 mL Nalgene bottle thermometer
  1. Remove a small piece of the skin from the green alien specimen by cutting piece off a small piece (8 cm x 8 cm) to test tube.
  2. Place the contents of the test tube into a clean 250 mL Nalgene bottle. Repeat this Section in total for each of the gas sensors identified in the materials section. Replace the word Oxygen with Methane and do steps 5 to 11. Replace the word Oxygen with CO2 and do steps 5 to 11.

Replace the word Oxygen with Nitrogen and do steps 5 to 11.

3. Use a computer and an Nitrogen sensor to measure the production of nitrogen gas 4. Connect the Nitrogen Gas Sensor to the computer interface. Prepare the computer for data collection by opening the file “06A Enzyme (Nitrogen)” from the Biology with Computers folder of Logger Pro. 5. Place the Nitrogen Gas Sensor into the bottle as shown in Figure 1. Gently push the sensor down into the bottle until it stops. The sensor is designed to seal the bottle without the need for unnecessary force. 6. When 30 seconds has passed, Click to begin data collection. 7. When data collection has finished, remove the Nitrogen gas sensor from the Nalgene bottle. Rinse the bottle with water and dry with a paper towel. 8. Move your data to a stored run. To do this, choose Store Latest Run from the Experiment menu. 9. Create a graph of the Nitrogen gas. Plot the values for the Nitrogen on the y-axis, and the time on the x-axis. 10. Examine Your Results? Write your explanation of the results below:


Lesson 2.2 Handout 5. ACTIVITY 4


New information has just been discovered about the aliens. The aliens’ skin is reported to taste sweet. One of the researchers accidentally placed one of the specimen samples in his mouth. We need to investigate what the skin contains that would make it sweet? Record everything in your individual lab journals.


Testing Specimens for Starch/Sugar (Activity)


Material Required


  1. Test Tube #50 ml Water (boiling)
  2. Erlenmeyer flask #White piece of paper towel
  3. 50 ml Tap Water (cold) # Sharpie Pen to label test tubes
  4. 1 Sample Specimens (1Green) # Razor cleaned with alcohol to cut specimens
  5. forceps (tweezers) # Iodine solution. (Tincture of iodine)
  6. 25ml alcohol (rubbing alcohol) # Test Tube Rack
  7. Dropper


REMEMBER TO ALWAYS WEAR SAFETY GLASSES

  1. Place water in beaker and boil
  2. Remove a small piece of the skin from the green alien specimen by cutting piece off a small piece (10 cm x 10 cm). Hold the specimen with forceps (tweezers) and dip it into a beaker of boiling water for about 30 seconds. This prevents any further reactions from occurring in the specimen.
  3. The second step is to put the specimen into a test-tube containing about 25ml of alcohol (rubbing alcohol is fine). Now place the test tube into a beaker of boiling water. CARE! CARE! CARE! The alcohol must not be close to a flame, so you must boil the water first. Turn off your heating appliance, and then put the test tube into the beaker of boiling water.
  4. Step three involves watching and waiting for the specimens green color to be removed. The alcohol will turn green. The more color you can remove from the specimen the better.
  5. Step four requires you to remove your specimen from the alcohol and to wash it in cold water to remove the alcohol.
  6. Now you are ready for step five. Spread your washed specimen on a clean, white surface (a clear plastic dish with a white piece of paper). Using a dropper, COVER the specimen with Iodine solution. (Tincture of iodine that you can buy at the drug store is fine.) CARE! CARE! CARE! Iodine solution should not be inhaled. If it gets in the eyes, it should be washed out immediately and professional advice should be sought. If your specimen contains starch, then the golden-brown iodine solution will become black in color.



Lesson 2.2 Handout 6.

ACTIVITY 5

Review all results from this lesson. How might you change the model you have been working on to determine the energy source of the aliens? Revise your model accordingly to reflect all the new information you obtained.

How does today’s activity relate to how scientists work in the real world ? Write your thoughts below:

Lesson 3.1

TITLE


Presentation of Alien Models and the Introduction to Photosynthesis


OVERVIEW


In the last lesson, the students completed their predictions and models for how the aliens obtain energy. In this lesson, the students will share and discuss their models. You will compare their predictions of how the aliens obtain energy to how plants obtain energy. The process of photosynthesis will be explained; the equation, inputs and outputs, and the importance of autotrophy for all life. Different exemplary models of photosynthesis will be shown. The students need to be reminded that they will continually revise their models of energy acquisition by the aliens as they learn about photosynthesis over the rest of the unit. In the next lesson, the students will look at the reactants and products of photosynthesis in more detail.


OBJECTIVES

Understanding Content:

  1. SWBAT describe the process of photosynthesis.
  2. SWBAT discuss the difference between organisms known as autotrophs and those known as heterotrophs as pertains to their mode of energy/nutrition.

Nature of Science:

  1. SWBAT understand that scientific knowledge is transferable and always changing as they revise their alien models based on the study of photosynthesis.


RELEVANT PRECONCEPTIONS


Since this is the first time photosynthesis is mentioned, all the main preconceptions on this topic are pertinent. The concept of energy and the relationship between energy and food was the most difficult for students. Students did not grasp that plants converted light energy to chemical energy to help them make food. Students expressed that plants need energy but in the way that they need water, and nutrients. It all just helped them “grow”. For food, many students said that plants needed soil, water, light. There was little distinction between the three as far as their role in providing energy for the plant. Also most of the students did not connect that plants make their own food strictly for themselves and not for the benefit of themselves or animals. Plants were seen as important because they “make” oxygen and we all need that to breath. Their focus was on oxygen production for others not food production for the plant.
In addition, the students were very uncomfortable with the chemical understanding of photosynthesis. They were not able to talk in terms of molecules and molecular equations. Their answers were vague. All life is essentially a series of reduction-oxidation reactions and it was hard for the students to discuss anything that they couldn’t see or touch.

Finally, the students had some idea of what photosynthesis was about but they could not provide definitive answers as to the mechanistic why of something. If asked about why plants need water, their answers ranged from because they get thirsty to they probably need it for photosynthesis. Their knowledge was not strongly connected to an explanation of photosynthesis. They seem to need a better understanding of the “why” of things.


CURRICULUM STANDARDS


  • New Jersey Standard 5.1- All students will develop problems solving, decision making and inquiry skills, reflected by formulating usable questions and hypotheses, planning experiments, conducting systematic observation, interpreting and analyzing data, drawing conclusions and communicating results.
  • New Jersey Standard 5.5- All students will gain an understanding of the structure, characteristics and basic needs of organisms and will investigate the diversity of life.
-Students will describe how plants produce substances high in energy content that become the primary source of energy for life.
-Explain how plants convert light energy to chemical energy.


MATERIALS AND PREPARATION

Time:

One to two class periods.

Materials:

Overhead transparencies: Models of photosynthesis Handout- Lesson 3.1/ Teacher’s Copy, Lesson 3.1 Handout 1.


ACTIVITIES


  1. Ask a representative from each group to write their predictive statement on the board and their supporting evidence in list format below. If possible, attach their model to the board next to or above their statement.
  2. Ask the student to remain at the board to read their statements out loud to the class. Compare and contrast their findings. Have the students analyze their findings and see how well their mechanisms account for the evidence. Ask the students to look for any weaknesses and/or strong points in their models as they pertain to the data. For instance, if a group said that the aliens obtained their energy from the vat of liquid, what about the Q’s that lived in the water? Were they able to explain their energy acquisition or was this information ignored? Why did they get sleepy on cloudy days? etc.
  3. Now it is time to move to the connection to plants. Ask the students questions to provoke the connection to plants. Do the aliens remind you of anything on earth? What? How? Eventually you should get to plants and any similarities between plants and the aliens. Have the students come up with the similarities and write them on the board.
  4. This is where you will introduce them to the process of photosynthesis. It is a basic description of photosynthesis because the following lessons will be more specific and in depth.
  5. Describe how plants get energy and as the discussion continues try to incorporate any of the student’s alien models that developed a similar mechanism.
  6. Put the models of photosynthesis on the overhead (sheet 3A) to help explain the process and the various ways it can be represented. Use the teacher’s copy (Lesson 3.1) to lead discussion. Make sure you cover:
  • The term autotroph
  • The conversion of sunlight to chemical energy
  • The terms chlorophyll and chloroplasts
  • Light and Dark reactions
  • Glucose is end product/ Oxygen is waste product
  • The term stoma
  • The equation of photosynthesis

7. You should emphasize that autotrophs are the only organisms capable of making their own food and that this stored energy is used by all heterotrophs- things that don’t make their own food but eat others. 8. The students need to complete the handout (Lesson 3.1) during the remainder of the class and then for homework. 9. It also needs to be clarified to the students that they will be revising their alien models throughout the rest of the unit as they learn how autotrophs obtain energy. This is the nature of science to update, revise or even change a scientific theory as new information is revealed.


DIFFERENTIATED INSTRUCTION


Multiple representations of photosynthesis will be used.


ASSESSMENT


This lesson is mainly a discussion and lecture. The student’s will be assessed on their participation during the model analysis. They will also be assessed on their worksheet responses for understanding the concept of photosynthesis.


Teacher’s copy PHOTOSYNTHESIS Lesson 3.1 Name: ________________

Directions: Please fill in all the blanks with the words listed below. Some words may be used more than once and some not at all. Translate the equation of photosynthesis into words. Photosynthesis is the process by which plants, and some bacteria –all known as autotrophs, use the energy from sunlight to produce sugar, the food for the plant. The conversion of unusable sunlight energy into usable chemical energy is done with the help of a green pigment chlorophyll. A pigment is any substance that absorbs light. The color of the pigment comes from the wavelengths of light reflected (in other words, those not absorbed). Chlorophyll, the green pigment common to all photosynthetic cells found in the chloroplast, absorbs all wavelengths of visible light except green, which it reflects to be detected by our eyes.

Photosynthesis occurs in two stages. The first stage is the light reactions. Light reactions begin when sunlight is absorbed by chlorophyll. The sun’s energy splits the water molecule into hydrogen and oxygen. The oxygen is released as a waste product.

The second stage is the dark reaction. Dark reactions begin when the hydrogen formed in the light reaction combines with carbon dioxide. These combined elements produce glucose-the plant’s food. Glucose gives the plant the chemical energy it needs to carry out its life processes.

The photosynthetic process uses water and releases the oxygen from the water molecule that we absolutely must have to stay alive. Indeed before, plants appeared; the earth’s atmosphere was high in carbon dioxide but contained no oxygen. The present atmosphere, by comparison, is about 0.035? carbon dioxide and 21% oxygen-thanks to photosynthesis. Photosynthesis is the beginning of the journey of energy from the sun to make the basic materials of life that flow from plant to animal to animal to decomposer.

The water needed by the plant enters the root and is transported up to the leaves through specialized plant cells. Land plants must guard against drying out (desiccation) and so have evolved specialized structures known as stomata to allow gas to enter and leave the leaf. Carbon dioxide cannot pass through the protective waxy layer covering the leaf, but it can enter the leaf through an opening (the stoma; plural = stomata; Greek for hole) flanked by two guard cells.

Likewise, oxygen produced during photosynthesis can only pass out of the leaf through the opened stomata. Unfortunately for the plant, while these gases are moving between the inside and outside of the leaf, a great deal of water is also lost. Cottonwood trees, for example, will lose 100 gallons of water per hour during hot desert days!!! Carbon dioxide enters single-celled and aquatic autotrophs through no specialized structures.

Oxygen stoma conversion chemical hydrogen light carbon dioxide chlorophyll chloroplasts water glucose photosynthesis stomata autotrophs sunlight blue green dark molecule electrical


We can write the overall reaction of this process as: 6H2O + 6CO2 --sunlight--------> C6H12O6+ 6O2 Most of us don't speak chemicalese, so the above chemical equation translates as: six molecules of water plus six molecules of carbon dioxide produce one molecule of sugar plus six molecules of oxygen http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html



3A-Models of photosynthesis


Lesson 3.1 Handout 1.

Name: ________________

PHOTOSYNTHESIS

Directions: Please fill in all the blanks with the words listed below. Some words may be used more than once and some not at all. Translate the equation of photosynthesis into words. _____________is the process by which plants, and some bacteria –all known as__________, use the energy from sunlight to produce sugar, the food for the plant. The _____________of unusable ________energy into usable ___________energy is done with the help of a green pigment___________. A ____________is any substance that absorbs light. The color that you see comes from the wavelengths of light reflected (in other words, those not absorbed).___________, the green pigment common to all photosynthetic cells found in the ____________absorbs all wavelengths of visible light except______________, which it reflects to be detected by our eyes. Photosynthesis occurs in two stages. The first stage is the ________reactions.________ reactions begin when sunlight is absorbed by_____________. The sun’s energy splits the water molecule into hydrogen and oxygen. The ______________is released as a waste product. The second stage is the _________reaction. ___________reactions begin when the hydrogen formed in the light reaction combines with carbon dioxide. These combined elements produce __________-the plant’s food. ____________gives the plant the chemical energy it need to carry out its life processes. The photosynthetic process uses water and releases the _________ from the water molecule, which we absolutely must have to stay alive. Indeed before, plants appeared, the earth’s atmosphere was high in _____________but contained no__________. The present atmosphere, by comparison, is about 0.035? ______________and 21% ____________thanks to photosynthesis. Photosynthesis is the beginning of the journey of energy from the sun to make the basic materials of life that flow from plant to animal to animal to decomposer. The __________needed by the plant enters the root and is transported up to the leaves through specialized plant cells. Land plants must guard against drying out (desiccation) and so have evolved specialized structures known as _____________to allow gas to enter and leave the leaf. Carbon dioxide cannot pass through the protective waxy layer covering the leaf, but it can enter the leaf through an opening (the___________; plural =_________; Greek for hole) flanked by two guard cells. Likewise, _________produced during photosynthesis can only pass out of the leaf through the opened_____________. Unfortunately for the plant, while these gases are moving between the inside and outside of the leaf, a great deal of water is also lost. Cottonwood trees, for example, will lose 100 gallons of water per hour during hot desert days!!! Carbon dioxide enters single-celled and aquatic autotrophs through no specialized structures.


Oxygen stoma conversion chemical hydrogen light carbon dioxide chlorophyll chloroplasts water glucose photosynthesis stomata autotrophs sunlight blue green dark molecule electrical energy


We can write the overall reaction of this process as: 6H2O + 6CO2 --sunlight--------> C6H12O6+ 6O2 Most of us don't speak chemicalese, so the above chemical equation translates as: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html

Lesson 4.1

TITLE

Reactants and products of Photosynthesis

OVERVIEW

In the previous lesson students discussed the connections which were made between aliens obtaining their energy and plants obtaining their energy. The main focus was on light CO2 and water. In this lesson students will learn the summary of photosynthesis, including reactants and products. Their understanding of basic chemical reaction is crucial, since later on they will be learning about the light and dark stages of photosynthesis.

OBJECTIVES

Understanding Content:

  • SWBAT write overall equation for photosynthesis using words and chemical symbols.
  • SWBAT recognize oxygen as a byproduct of photosynthesis.
  • SWBAT to analyze formula for photosynthesis, able to tell where reactants come from and where the products go.
  • SWBAT balance the equation of photosynthesis.

Nature of Science:

  • SWBAT use their newly acquired knowledge to revise their alien models.


RELEVANT STUDENT PRECONCEPTIONS

There is a common misconception about the plants that they take their food from the outside environment. This naïve conception obscures the concept of photosynthesis. Another common misconception is that water and carbon dioxide taken into plants are not changed. They are used in two important life processes, such as drinking and eating water and breathing the carbon dioxide. Many students do not know about the leaves playing a crucial role in photosynthesis. They do not know that the photosynthesis takes place inside of the leaves, that water and carbon dioxide travel to cells in the leaf, instead they think that water and carbon dioxide travel thorough the plant.


Standards

  • NSES Content Standard C, Life Science: Matter, Energy, and organization in living systems. Grades 9-12, page 186: Students should define and explain the equation of photosynthesis and oxygen as a byproduct. Emphasize the production of glucose as the purpose of photosynthesis and oxygen as a byproduct. Should explain the equation of photosynthesis (its reactants and products).
  • State Standards (NJ)

5.5. 12A. Matter, Energy and Organization in Living Systems

  • Explain how plants convert light energy to chemical energy.

Describe how plants produce substances high in energy content that become the primary source of energy for life.


Materials and Preparation


Time:

Two 40 minute period


Materials:

Handout 1.

  • Prepare with a reflection on Lesson 3.3
  • Hands-on activity
  • Inquiry lab
  • Group/cooperative learning
  • Review/reinforcement
  • Vocabulary 8

Activities

1) Activity 1.

Create a model of reactants’ and products’ of photosynthesis.

Notes to the teacher

Start this lesson with the driving question, such as: “Is what goes in really what goes out? When cells take in materials to make food, do they loss anything in the process? Write the equation for photosynthesis on the board, but let students to dictate you the input. You may have different versions of the photosynthesis reaction. Have students to discuss and debate which one and why is the correct reaction. After the debate very short lecture might be necessary. Kids may have forgotten the conversion of mass. Very superficially it can be refreshed, since it is important to understand in order to balance the reaction of photosynthesis. The philosophy of this experiment is that the students first do their own work, based on it they ask questions, and only at the end, when the activity is done and all students’ questions are answered, the teacher should explain the lesson. The following materials are required for activity 1.

Materials required:

  • Student worksheet
  • Student cut-out sheet
  • Paper towels
  • Skittles separated by color and numbered (36)
  • Dixie cups for the skittles
  • Scissors

Along with above mentioned materials teacher should hand over students the handout 1. While kids are engaged and exploring their models of reactants and products of photosynthesis the teacher should tour the classroom and make sure that the kids are on the right track. For example, their set-up should have the symbols above the paper towels laid out in the correct order. If the student made a mistake at the beginning then she/ he will have a problem with arranging the skittles for forming the correct molecules in each step of the reaction. Another hint: it should be easy to spot check the Skittles laid out as you walk past. Students should have used all of one color (the oxygen).

Assessment for activity 1


The teacher can give this rubric to the students which will give them a feedback about their evaluation.

CATEGORY4321
Worksheet 1All variables are clearly described with all relevant detailsAll variables are clearly described with all relevantMost variables are clearly described with most relevant detailsVariables are not described or the majority lack sufficient detail
Worksheet 2Professional looking and accurate representation of the data in tables. Tables and are labeled and titledAccurate representation of the data in tables. Tables are labeled and titledTables are not accurate representation of the dataNo tables are presented
ActivityProfessional looking and accurate representation of the equationAccurate representation of the equationThe model was not an accurate representation of the equationNo model is presented
ParticipationPlayed an active role in the class discussion of the activityParticipated in or actively listened to the class discussionListened somewhat to the discussionNo attention or participation in the discussion


2) Activity 2.

Notes to the teacher

This activity helps students to discover many basic facts of photosynthesis. Students will be able to see that oxygen is a byproduct of photosynthesis and carbon dioxide is one of the reactants. This activity takes place through the lab experience. By the way this activity is included in the state standards. Students place aquatic Elodea plants in test tubes full of aquarium water and expose the test tubes to lamps placed at varying distances (5 cm outward). Then students cut the stems of the Elodea on a diagonal and place them in the test tubes upside down. Oxygen bubbles form on the cut end of the stems at a rate related to the distance from the lamp. (Here the teacher can highlight that both sunlight and artificial light are considered as light sources). Students should determine if carbon dioxide is taken up by plants when the plants are exposed to light. In order to be able to conduct these experiments the students should use carbon dioxide indicator, which is called bromothymol blue. Students place a few drops of bromothymol blue in the test tube which was partially filled with water. They exhale through a straw into the test tube until the color turns yellow. They students place an Elodea plant in the water in the test tube and expose to light. Kids should understand that Bromothymol blue is not harmful to Elodea. As the plant absorbs carbon dioxide, the yellow color changes back to blue.


Materials: • A plant (Elodea) • Lamp • Water • Cutting tools • Bromothymol blue • Straw

Vocabulary Chlorophyll: A green substance which gives leaves their color. Chlorophyll absorbs energy from sunlight which a plant uses to make food. Chloroplast: A plastid that contains chlorophyll and is the site where photosynthesis and starch formation occur. Photosynthesis: The formation of carbohydrates in the chlorophyll-containing tissues of plants exposed to light. Stomata: A very small hole in the surface of a leaf. Oxygen and carbon dioxide from the air enter through the stomata; oxygen, carbon dioxide and water vapor leave through the Summary of the photosynthesis chemical reaction:

6CO2+6H2O ----------------------------> C6H12O6+6O2+Q (energy)




Lesson 4.1 Handout 1


Name: Date:


1. Write the equation for photosynthesis here:



2. For the reactant side of the equation write each chemical formula, the name of the molecule it stands for and the number of each molecule:


Formula Name Number


_________________ = ________________________ ______

_________________ = ________________________ ______



3. What is the source of energy for this equation to take place? ___________


4. For the product side of the equation write each chemical formula, the name of the molecule it stands for and the number of each molecule:


Formula Name Number


_________________ = ________________________ ______

_________________ = ________________________ ______


5. Write the names and symbols of the three elements used in this equation and color you will make this element (red, orange, purple, green, or yellow).

Symbol Name Color

___________ = _____________________ = ____________

___________ = _____________________ = ____________

___________ = _____________________ = ____________


You have to build equation of photosynthesis. Each piece will represent one element. First, cut out and arrange the pieces of the equation on your table. Under each piece lay a piece of paper towel. Next, arrange your skittles to form the molecules in each step of the reaction.


6. Fill in the following chart with the numbers of each element based on your model in front of you.


Reactants Products


Number of Carbon Number of Hydrogen Number of Oxygen Total numbers (add up first 3 columns)


7. The number of elements on the side of the reactant is _______________.


The number of elements on the side of the product is _________________.


What conclusion can you draw from this? ____________________________ ________________________________________________________________________ ________________________________________________________________________ ______________________________________. 8. What molecule represents food that is made in photosynthesis? _____________________________________________________________. 9. List the reactants ___________________________________________ _____________________________________________________________ 10. List the products. ___________________________________________

Lesson 4.2

THE ROLE OF CHLOROPHLL IN PHOTOSYNTHESIS.


OVERVIEW

In the previous lesson, 4.1 students examined the reactants and products of photosynthesis and conducted labs to investigate the role each played in photosynthesis. They discovered light and carbon dioxide are inputs where sugars and oxygen are the outputs. In this lesson students will look at the primary pigments for photosynthesis in plants. They will examine how chlorophyll in the chloroplast absorbs light and how and why is an integral part in the process of photosynthesis. They will explore how pigments trap energy in the form of a photon and this energy is used to drive the process of photosynthesis.


OBJECTIVES

Understanding Content:


  1. SWBAT understand and explain the properties of pigments (chlorophyll and accessory pigments) in chloroplast and their function in photosynthesis
  2. SWBAT explain, in their own words, what chloroplasts are and their role in the photosynthesis.
  3. SWBAT summarize the photochemical reaction of photosynthesis.


RELEVANT STUDENT PRECONCEPTIONS


From interviews conducted, students confused chloroplast with chlorophyll. Most of them knew it could be found in leaves but didn’t understand its role in photosynthesis. Only a few of the students knew the leaves were green because of chlorophyll or chloroplast. Three students knew that photosynthesis took place in chloroplast. These three students mentioned different light waves and something to do with color but couldn’t put it into the why the leaves are green. Energy was the most difficult concept for the students to understand. Every student mentioned the word force; some mentioned work or motion. Typical answers were, “It’s a force…a force that is found in nature”, and “a force, um power and things that move or things that involve moving them”. They seemed to think that energy is a thing that is either created or found in nature. They intuitively knew that there were different types of energy and could name some types but beyond that they were very confused. None of them understood how energy was converted. Some of them had a notion of a “change” or “reaction”. Some of them thought that light itself was the food for the plant and only a few understood that it is used to make food.


CURRICULUM STANDARDS

  • New Jersey Core Curriculum Content Standards Standard 5.5 A.2 and A.3.

The study of science must include the diversity, complexity, and interdependence of life on earth. Students should know how organisms evolve, reproduce.

A. Matter, Energy and Organization in Living Systems 2. Explain how plants convert light energy to chemical energy. 3. Describe how plants produce substances high in energy content that become the primary source of energy for life.

  • National Science Education Standards Content Standard C

Life Science: The cell

Plant cells contain chloroplasts, the site of photosynthesis. Plants and many microorganisms use solar energy to combine molecules of carbon dioxide and water into complex, energy rich organic compounds and release oxygen to the environment. This process of photosynthesis provides a vital connection between the sun and the energy needs of living systems.

  • National Science Education Standards Content Standard C

Life Science: Matter, energy, and organization in living systems

The energy for life primarily derives from the sun. Plants capture energy by absorbing light and using it to form strong (covalent) chemical bonds between the atoms of carbon-containing (organic) molecules. These molecules can be used to assemble larger molecules with biological activity (including proteins, DNA, sugars and fats). In addition, the energy stored in bonds between the atoms (chemical energy) can be used as sources of energy for life processes.

  • National Science Education Standards Content Standard C

Physical Science: Chemical reactions

Chemical reactions may release or consume energy. Some reactions such as the burning of fossil fuels release large amounts of energy by losing heat and by emitting light. Light can initiate many chemical reactions such as photosynthesis and the evolution of urban smog.



MATERIALS AND PREPARATION

Time:

Two 40 minute lessons.

Materials:

  • Handout 1 - Do Now
  • Handout 2 - Diagram of Leaf Cells
  • Handout 3 - Diagram of Chloroplasts
  • Handout 4 - Energy Transfer In Photosynthesis Chlorophyll Fluorescence Lab
  • Handout 5 - Absorption Spectrum for Several Pigments
  • Web access
  • Spinach Leaves
  • Mortar and pestle
  • Acetone
  • 25-mL graduated cylinder
  • Ring stand or funnel rack
  • Flashlight or small lab light
  • 2 Test Tubes
  • Filter paper
  • Funnel
  • Safety goggles
  • UV light source


NOTES TO THE TEACHER

This lesson is very hands on with one lab experiment. Please review all materials and procedures before start of activities. There are two additional notes to teacher at the end of this document pertaining to the lab.


ACTIVITIES


  1. DO NOW - Write the following on the board: Green plants have five closely related photosynthetic pigments (in order of increasing polarity):
  • Carotene - an orange pigment
  • Xanthophylls - a yellow pigment
  • Chlorophyll a - a blue-green pigment
  • Chlorophyll b - a yellow-green pigment
  • Phaeophytin - a gray pigment


A. Pass out handout 5 to each student.
B. Ask students to answer the question on the handout (answers show below). They will use knowledge gained from previous lecture as well as previous assigned readings.
C. Have students hand in questions before discussion (for a formal assessment)
D. Go over questions with class


What does the word chlorophyll mean?
Its name is derived from ancient Greek: chloros = green and phyllon = leaf


What is a photosynthetic pigment? Also called antenna pigment is a pigment that is present in chloroplasts or photosynthetic bacteria and captures the light energy necessary for photosynthesis.


What is Chlorophyll? Chlorophyll is a green photosynthetic pigment found in most plants, algae, and cyanobacteria. Chlorophyll absorbs most strongly in the blue and red but poorly in the green portions of the electromagnetic spectrum, hence the green color of chlorophyll-containing tissues like plant leaves.


Looking at the board and the five pigments list. Why do you think there is more than one type of pigment? Chlorophyll a is the most common of the five, present in every plant that performs photosynthesis. The reason that there are so many pigments is that each absorbs light more efficiently in a different part of the spectrum. Chlorophyll absorbs well at a wavelength of about 400-450 nm and at 650-700 nm; chlorophyll b at 450-500 nm. Xanthophyll absorbs well at 400-530 nm. However, none of the pigments absorbs well in the green-yellow region, which is responsible for the abundant green we see in nature.


Why is it advantageous for plant to have more that one type of pigment? Capture more light energy.
Is there more than one pigment in a leaf? To answer this question we will conduct an investigation


2. Play the Web Tutorial 8.1of Parts of Light (Part 1: Animation) ONLY at http://wps.prenhall.com/wps/media/objects/1109/1135896/8_1.html Review tutorial with class and informally assess class understanding

3. Play the Web Tutorial 8.1of Parts of Light (Part 2: Exercise) ONLY at http://wps.prenhall.com/wps/media/objects/1109/1135896/8_1.html Conduct exercise with class and informally assess class understanding

4. Play the Web Tutorial 8.1of Parts of Light (Part 3: Exercise) ONLY at http://wps.prenhall.com/wps/media/objects/1109/1135896/8_1.html Conduct exercise with class and informally assess class understanding

5. Label exercise. After showing tutorials have students break up into groups of 3 or students will remain in groups of 3 or 4 for the remainder of Lesson. Hand out to each group Handout Number 2 and Handout Number 3. Note: Labels need to be removed before copying and handing out to students. Ask each group to fill in the labels when complete review as a class


BREAKPOINT


6. Experiment 1 - Distribute Handouts 4 and 5 to each student to instruct students on experiment 1. Students will remain in groups of 3 or 4 for the remainder of Lesson. Conduct Experiment 1.

7. Play the web Tutorial at http://www.phschool.com/science/biology_place/labbench/lab4/dpipex.html to provide a summarization of lesson.

8. Assign students homework to update their models using newly acquired information. Remind them that the driving question is “How do Q’s obtain their energy?”

9. Remind students lab journals are graded and are due in 5 day.



TEACHER NOTE

The following is what the students will view when shining the uV light on test tubes:


Reflected Light white light source


Re-Transmitted Light (florescence) uV light source


UV Light result 1


Lesson 4.2 Handout 1.

Instructions: This is a “Do Now”. Please answer the following questions and return to your teacher when completed. You have approximately 7 minutes. You will be graded on your answers provided. If you do not know, take a guess. Think creatively and think about what you have learned from your introduction to photosynthesis and readings.


What does the word chlorophyll mean?


What is a photosynthetic pigment?



What is Chlorophyll?



Looking at the board and five pigments list. Why do you think there is more than one type of pigment?



Why is it advantageous for plant to have more that one type of pigment?



Is there more than one pigment in a leave?




Lesson 4.2 Handout 2.


DIAGRAM OF LEAF CELLS

Cell-





Lesson 4.2 Handout 3.



DIAGRAM OF CHLOROPLASTS



Chloroplast



Where is the chlorophyll in the picture above? Chlorophyll molecules cluster on the surface of the chloroplast of a leaf. The chloroplasts on an average maple tree have an average surface area of 140 square miles when spread out. This means that there are an uncountable number of chlorophyll molecules on just one tree.





Lesson 4.2 Handout 4.


ENERGY TRANSFER IN PHOTOSYNTHESIS CHLOROPHYLL FLUORESCENCE LAB

MATERIALS

  • Spinach Leaves
  • Mortar and pestle
  • Acetone
  • 25-mL graduated cylinder
  • Ring stand or funnel rack
  • Flashlight or small lab light
  • 2 Test Tubes
  • Filter paper
  • Funnel
  • Safety goggles
  • UV light source


PROCEDURE

Just what color are spinach pigments when extracted from plant cells? Green right? Wrong! In this lab you will investigate the color of spinach pigments under varying light conditions and observe their color. You will also investigate the phenomenon of fluoresce, reflection and transmission of light. Document all procedures, data and results in your lab journal. Lab journals will be collected and graded and are due five days from today

Lab Steps

  1. Grind the spinach leaves using a mortar and pestle. SAFETY: The following needs to be conducted under a hood.
  2. Add acetone to the ground leaves, using enough acetone and spinach leaves to get between 10 and 15 mL of extract.
  3. Set up your filtering apparatus, and using proper filtering techniques; filter the extract to a test tube. NOTE: Use small amount of acetone to wet the filter paper, to hold it into place, instead of water.
  4. Shine a flashlight, or other similar light source, through the test tube and extract.
  5. Observe the fluorescence of the chlorophyll at a 90-degree angle to the flashlight.
  6. Shine an uV light source through the test tube and extract.
  7. Observe the fluorescence of the chlorophyll using uV light source.

ANALYZE RESULTS

Answer the following four questions in your lab journal as homework that is due 5 days from today. You will need to use current knowledge you have gained so far during class, reading and conducting this lab. You will need to use evidence as to prove you answer. Also use the Absorption Spectrum in Handout 4 to help answer as well.

8. Explain the phenomenon of fluorescence, reflection and transmission you have observed.

9. Just what color are spinach pigments when extracted from plant cells?

10. Why don't normal intact spinach leaves re-transmit this red light when you shine a flashlight on them?

11. Explain the difference of observation verses inference YOU encountered while performing this lab experiment


Note To Teacher

Here are answers to a few of the questions in lab:

Why don't normal intact spinach leaves re-transmit this red light when you shine a flashlight on them?

Answer for teacher: When a pigment molecule absorbs a photon of light energy, one of its electrons becomes energized, which means that the electron shifts from a lower energy atomic orbital to a high-energy orbital that is more distant from the atomic nucleus. One of two things then happens, depending on the atom and its surroundings. The atom may return to its ground state, which is the condition in which all its electrons are in their normal state, lowest energy levels. When an electron returns to its ground state its energy is dissipated as heat or as an emission of light of a longer wavelength than the absorbed light, this emission of light is called fluorescence. This is what we observed with the flashlight. Alternatively, the energized electron may leave the atom and be accepted by an electron acceptor molecule, which becomes reduced in the process: this what occurs in photosynthesis.

The energy of an absorbed photon is converted to the potential energy of the electron that has been raised to excited state. In the chloroplast, these excited electrons jump from the chlorophyll molecule to a protein molecule in the thylakoid membrane, and are replaced by (hydrogen) electron from the splitting of water. The energy thus transferred, is used in carbohydrate production. During photosynthesis an electron acceptor captures the energetic electron and passes it to a chain of acceptors.


Chlorophyll Pigment Extract

Just what color are spinach pigments when extracted from plant cells? Green right? Wrong! Answer for teacher: That depends on the type of light you are using to view the pigments with! All molecules absorb a portion of the electromagnetic spectrum. Biological pigments are chemicals that absorb a portion of the visible light spectrum.

The acetone / spinach extract solution under normal room light appears green due to the white room light reflecting off of the pigment molecules. A few of these photons of light actually pass through the molecules and are unaltered by the pigment. These photons of white light are transmitted light photons.

This extract is composed of primarily of chlorophyll a and b. However, if you use a high-energy source light such as a common uV light ("black light") you see something entirely different. Shorter wavelengths of the visible light spectrum (violet) are composed of much higher energy packets of light (photons). This energy interacts with the pigment molecules and is actually re-transmitted or emitted from the molecules in a process known as florescence. The wavelength emitted at a lower energy level, hence the red color portion of the color spectrum of visible light. This follows with the 2nd law of thermodynamics, as one would predict that as the higher energy light is re-transmitted it would have some unusable energy (entropy) as a part of the system.

Take a look below at pigments extracted from spinach leaves with acetone both under reflected room white light and then the re-transmitted lower energy light when illuminated with a high energy (short wavelength) uV light source.



Explain the difference of observation verses inference YOU encountered while performing this lab experiment. The distinction between observation and inference. Observations are “directly” accessible to the senses (or extensions of the senses) and about which several observers can reach consensus with relative ease. Inferences are statements about phenomena that are not “directly” accessible to the senses.














Lesson 4.2 Handout 5.

LAB HANDOUT

ABSORPTION SPECTRUM FOR SEVERAL PIGMENTS


Absorption spectra

Lesson 4.3

TITLE

Light and dark reactions, CAM plants and the rate of photosynthesis

OVERVIEW

In the previous lesson students examined the role of pigments and light in photosynthesis with an accompanying lab. After the lab work students learned that chlorophyll and sun light are important factors of photosynthesis. Today’s experiment will help students understand that without enough sunlight, plants cannot use the process of photosynthesis to produce food. Students will get familiarized with two stages of photosynthesis and CAM plants as well. Lab activities, practical applications, scientific articles about the photosynthesis will provide students a hands-on opportunity to gain an appreciation for photosynthesis. After the labs are conducted, the other activities can be scattered throughout the lesson or used in the rotation with small groups. Since this lesson is the final lesson of the photosynthesis unit, students will get assignments about all major points and concepts of photosynthesis. They should be encouraged to work on some of these assignments at home, some of them at school.

Objectives

Understanding Content:

  • SWBAT distinguish between the two stages of photosynthesis: light and dark reactions
  • SWBAT summarize the basic process by which the light and dark reactions of photosynthesis convert solar energy to chemical energy.
  • SWBAT to write the formula for photosynthesis, but should know where reactants come from and where products go as well.
  • SWBAT understand the photosynthetic adaptations CAM and C3 plants developed.

Inquiry:

  • SWBAT recognize main factors that affect the rate of photosynthesis.
  • SWBAT design their own hypothesis and conduct the experiment based on their hypothesis.

Nature of Science:

  • SWBAT develop scientific ideas developed through reasoning.
  • SWBAT understand that scientific knowledge is at least partially based on and/or derived from observations of the natural world.


RELEVANT STUDENT PRECONCEPTIONS

Most of the kids think that plants die when it is dark. In their understanding cacti do not perform photosynthesis, since they do not have leaves. Most of the kids are not aware of the two different stages of photosynthesis. However, if some of they are aware, most of them think that light reaction takes place in the presence of light, while dark reaction takes place in dark. This preconception should be addressed and it should be made clear to the students that light reactions take place in the presence of light and dark reactions do not require direct light. Furthermore, students should be aware that dark reactions in most plants occur during the day.

STANDARDS

  • New Jersey Core Curriculum Content Standards: Students best learn science by doing science. Science is not merely a collection of facts and theories but a process, a way of thinking about and investigating the world in which we live. This standard addresses those skills that are used by scientists as they discover and explain the physical universe - skills that are an essential and ongoing part of learning science.
  • NSES Content Standard: Plant cells contain chloroplasts, the site of photosynthesis. Plants and some other organisms, use solar energy to combine molecules of carbon dioxide and water into complex, energy rich organic compounds. This process of photosynthesis provides a vital connection between the sun and the energy needs of living systems.
  • Understand that plants convert light energy into chemical energy. Know that high-energy carbon compounds produced by plants, carbohydrates and fats, are the primary source of energy for all animal life.

MATERIALS AND PREPARATION

Time:

Two 40 minute periods Prepare with a reflection on Lesson 4.1 and 4.2 Hands-on activity Inquiry lab Group/cooperative learning Review/reinforcement

Materials:

Handout 1,2,3

Activities

Before doing any activity review last lesson’s key points.

  1. Show them pictures of different plants. Ask them if they can differentiate between the pictures. The purpose is a short lecture about different plants having different types of photosynthesis. The picture shows different leaves, with different sizes. The idea here is that all plants do photosynthesis, even those who live in dessert.

Plant1Plant2Plant3Plant4Plant5Plant6Plant7Plant8Plant9


Notes to the teacher

Teacher can address the following to the class: scientists used to think that all plants did photosynthesis in exactly the same way, but in the last 30 years they have found that at least three different ways photosynthesis can occur. The three photosynthetic pathways are called C3, C4, and CAM. The future Pre-Lab and Post-Lab work should be done based on C3 and CAM plants. Since there is not so much time left, the details about C4 plants will be excluded. Kids should know that most of the plants use the C3 pathway. A second type of photosynthesis is called C4 and involves plants like corn and sugar cane. There is no need here to go into details. However, kids should be familiar about the third method of photosynthesis, called CAM (Crassulacean Acid Metabolism). This pathway is employed by succulent plants like ice plant, jade plant and aloe as well as some cacti. The CAM pathway is used by plants that live in environments that have high light levels, high temperatures but low levels of moisture in the summer. CAM photosynthesis takes place in two stages. The first stage takes place at night when the stomas of the plant are opened. CO2 enters the leaf through the open stoma and is fixed and stored as an acid. The second stage of the CAM process takes place during the daytime while the stomas are closed.

a) Students should answer the following questions Some of these questions are critical thinking questions, besides this will refresh their previous knowledge about photosynthesis.

  1. What four materials are needed by all plants for photosynthesis to take place?
  2. What two products are produced?
  3. What is the main difference between the environments of C3 plants and CAM plants?
  4. What might have caused plants to develop these different pathways?
  5. Fill in the chart below about the three different pathways:

b) Students should fill out the table below. They should put an “X” in the column that the statements refer to. ( Handout 1)

c) After this activity there will be a discussion. This discussion is important for the teacher, because he/she will see what was missed or misunderstood. The discussion will be beneficial for the kids, since they will have to complete homework, which will be graded. Below is the list of the questions for homework. (Assessment 1)

  1. During the cool of evening CAM plants open their stomata. What gas is absorbed ? Explain how this gas is stored for daytime use.
  2. If you were a researcher looking for new plant species which exhibited CAM photosynthesis, what biome or biomes would be most rewarding for you to explore? Here is the list of biomes, in case if you have forgotten.

tundra, rainforest, savanna, taiga, temperate forest,temperate grassland, dessert

  1. If the greenhouse effect gets worse which photosynthetic pathway (C3, CAM) could benefit the most? Explain why.
  2. The short supply of which factor will affect CAM photosynthesis the most? (light, temperature, water, photo respiration) Explain why.



2) Activity 2.

Notes to the teacher

Students will be introduced with different factors that affect the rate of photosynthesis. Below written information can be either put nicely on the poster or preferable can be done as a power point presentation.

a) Explain different factors that affect the rate of photosynthesis.

Factors affecting photosynthesis rate

It can be affected by many factors, such as

  • Sunlight - its intensity and wavelength
  • Temperature
  • Co2 and O2 - availability
  • Any factor that influences the production of the chlorophyll, enzymes or energy carrier (ATP and NADPH)

Sunlight

Generally the more light there is, the more photosynthesis occurs. This is true up to a point, when the plant reached to maximum photosynthesis level and so any increase in light intensity will not affect the plant.

Temperature

Generally higher temperatures are better than cold temperatures for photosynthesis. However, when it is humid or the air is saturated with water vapor, photosynthesis is limited. The water vapor sits on the leaf and stops photosynthesis.

CO2

The more CO2 in the air, the better the rate of photosynthesis is.

Water and CO2

Plants need water for photosynthesis. If they lack it they wilt. When they have a deficiency of water, they stomata close, so CO2 can not diffuse into the leaves.

3) Activity 3.

Students will make models of chloroplasts. The purpose of the model is to understand different parts of chloroplasts as being responsible for two different stages of photosynthesis. Since this lesson is the last one in the unit, it will help to recap the understanding of the chloroplast’s structure as well, which they learned at the beginning of the unit.

Materials:

• Paper plates • Plastic bags • Green Construction paper • Scissors

The models should look like this

Model2

The paper plates supposed to model the chloroplasts. Using plastic two ties of plastic bags students will represent the membrane of the chloroplast. From the green construction paper students will make small circles, representing chlorophyll. Their final project should be consisted of two plates. One plate should show the location that light reaction takes place (the thylakoid stacks of grana), while the other plate should represent the location where the dark reaction takes place (the stroma). The main purpose of this activity for kids is to understand that dark and light reactions take place in different locations.


Group discussion 1)

Notes to the teacher Divide the class in 4-5 groups. Give them the handout 2. After about 15 minutes each group should come with a solution. After that the best solution will be voted on and each individual should provide explanations why she/he chose that particular solution. (Handout 2)

Group discussion 2)

Have an article review and debate about the article called “Source of Half Earth's Oxygen Gets Little Credit “ , which was published on June 7, 2004 in National Geographic magazine. (Handout 3)


Lesson 4.3

Handout 1.

CharacteristicsC3CAM
The type of photosynthesis used by most of the plants
The type of photosynthesis done by many cacti and succulent plants
Involves the fixation of CO2
Takes place entirely during the daytime
Takes place partly during the night and partly during the day
Found in environments with high light, high temps, low water
Found in environments with high light, average temps and lots of water

Lesson 4.3

Handout 2.

It is the year 2040 and you are a research scientist. The amount of sunlight that reaches the earth has been reduced because of some major event like pollution, volcanoes or global fires. Farmers are asking you for help to save their failing crops. Figure out ways that you might help and put your notes below.












Lesson 4.3

Handout 3.

Source of Half Earth's Oxygen Gets Little Credit

John Roach for National Geographic News June 7, 2004

Fish, whales, dolphins, crabs, seabirds, and just about everything else that makes a living in or off of the oceans owe their existence to phytoplankton, one-celled plants that live at the ocean surface. Phytoplankton are at the base of what scientists refer to as oceanic biological productivity, the ability of a water body to support life such as plants, fish, and wildlife. "A measure of productivity is the net amount of carbon dioxide taken up by phytoplankton," said Jorge Sarmiento, a professor of atmospheric and ocean sciences at Princeton University in New Jersey. The one-celled plants use energy from the sun to convert carbon dioxide and nutrients into complex organic compounds, which form new plant material. This process, known as photosynthesis, is how phytoplankton grow. Herbivorous marine creatures eat the phytoplankton. Carnivores, in turn, eat the herbivores, and so on up the food chain to the top predators like killer whales and sharks. But how does the ocean supply the nutrients that phytoplankton need to survive and to support everything else that makes a living in or off the ocean? Details surrounding that answer are precisely what Sarmiento hopes to learn. Robert Frouin, a research meteorologist with the Scripps Institution of Oceanography in La Jolla, California, said understanding the process by which phytoplankton obtains ocean nutrients is important to understanding the link between the ocean and global climate. "Marine biogeochemical processes both respond to and influence climate," Frouin said. "A change in phytoplankton abundance and species may result from changes in the physical processes controlling the supply of nutrients and sunlight availability."

Oxygen Supply

Phytoplankton needs two things for photosynthesis and thus their survival: energy from the sun and nutrients from the water. Phytoplankton absorbs both across their cell walls. In the process of photosynthesis, phytoplankton release oxygen into the water. Half of the world's oxygen is produced via phytoplankton photosynthesis. The other half is produced via photosynthesis on land by trees, shrubs, grasses, and other plants. As green plants die and fall to the ground or sink to the ocean floor, a small fraction of their organic carbon is buried. It remains there for millions of years after taking the form of substances like oil, coal, and shale. "The oxygen released to the atmosphere when this buried carbon was photosynthesized hundreds of millions of years ago is why we have so much oxygen in the atmosphere today," Sarmiento said Today phytoplankton and terrestrial green plants maintain a steady balance in the amount of the Earth's atmospheric oxygen, which comprises about 20 percent of the mix of gasses, according to Frouin. A mature forest, for example, takes in carbon dioxide from the atmosphere during photosynthesis and converts it to oxygen to support new growth. But that same forest gives off comparable levels of carbon dioxide when old trees die. "On average, then, this mature forest has no net flux of carbon dioxide or oxygen to or from the atmosphere, unless we cut it all down for logging," Sarmiento said. "The ocean works the same way. Most of the photosynthesis is counterbalanced by an equal and opposite amount of respiration."

Carbon Sink

The forests and oceans are not taking in more carbon dioxide or letting off more oxygen. But human activities such as burning oil and coal to drive our cars and heat our homes are increasing the amount of carbon dioxide released into the atmosphere. Most of the world's scientists agree that these increasing concentrations of carbon dioxide in the atmosphere are causing the Earth to warm. Many researchers believe that this phenomenon could lead to potentially catastrophic consequences. Some researchers argue that enriching the oceans with iron would stimulate phytoplankton growth, which in turn would capture excess carbon from the Earth's atmosphere. But many ocean and atmospheric scientists debate whether this would indeed provide a quick fix to the problem of global warming. Research by Frouin and his Scripps Institution of Oceanography colleague Sam Iacobellis suggests an increase in phytoplankton may actually cause the Earth to grow warmer, due to increased solar absorption. "Our simulations show that by increasing the phytoplankton abundance in the upper oceanic layer, sea surface temperature is increased, as well as air temperature," Frouin said. As Sarmiento notes, phytoplankton obtains most of its carbon dioxide from the oceans, not the atmosphere. "Pretty much all of the carbon dioxide taken up by phytoplankton comes from deep down in the ocean, just like nutrients, where bacteria and other organisms have produced it by respiring the organic matter that sank from the surface," Sarmiento said.

Lesson 5.1

TITLE

Poster Boards

OVERVIEW

Each group of students will create a representation on their model. They will incorporate all revisions they agreed upon while learning about photosynthesis.

OBJECTIVES

SWBAT create a representation of their alien model.

STANDARDS

There are no relevant standards.

MATERIALS AND PREPARATION

Time: One 40 minute lesson Materials: Glue Scissors Coloring Pencils Foam Display Board Web access Computer printer Handout 1. Handouts 4 and 5 from lesson 1.2

ACTIVITIES

Students, in their groups, build their poster presentation boards. You should give them handout-1 for a guideline on creating a display board. Students may also find handouts 4 and 5 from lesson 1.2 very useful. Students can use Google image search to supplement their graphics.

DIFFERENTIATED INSTRUCTIONS

You may monitor the work division within the groups to make sure every student is involved in the process.

ASSESSMENT

In this class students are not assessed formally. Their display boards will be graded in lessons 5.2 and 5.3.

HANDOUTS

Lesson 5.1 Handout 1.

What Makes for a Good Science Project Display Board?

Does your display board include:

  1. Title
  2. Abstract
  3. Question
  4. Variables and hypothesis
  5. Background research
  6. Materials list
  7. Experimental procedure
  8. Data analysis and discussion including data chart(s) & graph(s)
  9. Conclusions (including ideas for future research)
  10. Are the sections on your display board organized like a newspaper so that they are easy to follow? Yes / No
  11. Is the text font large enough to be read easily (at least 16 points)? Yes / No
  12. Does the title catch people's attention, and is the title font large enough to be read from across the room? Yes / No
  13. Did you use pictures and diagrams to effectively convey information about your science fair project? Yes / No
  14. Have you constructed your display board as neatly as possible? Yes / No
  15. Did you proofread your display board? Yes / No

Lesson 5.2

TITLE

Why do we study photosynthesis?

OVERVIEW

Lesson 5.1 and 5.2 are designed as a conclusion of the entire photosynthesis unit. In the first part of lesson 5.1 Students discuss the unique role and importance of photosynthetic organisms to all life. Each group presents their poster board of the model they created based on what they learned throughout the entire unit. Lesson 5.2 concludes the presentations and ends with a test. The test assesses students’ understanding of the material and Nature of Science with special emphasis on scientific models.

OBJECTIVES

Understanding Content

  1. SWBAT explain the importance of photosynthetic organisms to all life.

Nature of Science

  1. SWBAT understand the roles of models in science.
  2. SWBAT list and explain the characteristics of a good (as it pertains to science) model.

RELEVANT STUDENT PRECONCEPTIONS

This lesson is the last one in the unit it is designed as a review only. Therefore, all preconceptions associated with the photosynthesis and scientific models would be addressed in the previous lessons.

STANDARDS

There are no standards relevant to the topics covered in this lesson.

MATERIANLS AND PREPARATION

Time: Two 40 minute lessons Materials:

  • Poster boards created by students.
  • Handout 1. - Lesson 5.2 “Assessment Table”
  • Handout 2. – Lesson 5.2 “Guidliness”

NOTES TO THE TEACHER

This lesson is a discussion based lesson, with more freedom than previous lessons.

ACTIVITIES

Discuss with students why it is important to study photosynthesis.

Possible Student Answers

  1. Plants produce oxygen.
  2. Plants are source of food.

There are also less obvious yet important aspects of photosynthesis that you can include in the discussion. If students do not mention all of them, you can point them in the right direction by giving them more information. Ask leading questions such as:

  • What impact can photosynthesis have on agriculture?
  • What kind of fibers and other materials come from photosynthetic organisms?

To guide the discussion use the following outline:

Photosynthesis and…

  1. Food: All of our biological energy needs are met by the plant kingdom, either directly or through herbivorous animals. One widely accepted theory explaining the extinction of the dinosaurs suggests that a comet, meteor, or volcano ejected so much material into the atmosphere that the amount of sunlight reaching the earth was severely reduced. This in turn caused the death of many plants and the creatures that depended upon them for energy.
  2. Energy: Knowledge gained from photosynthesis research can be used to enhance energy production in a much more direct way. Scientists can now synthesize artificial photosynthetic reaction centers which rival the natural ones in terms of the amount of sunlight stored as chemical or electrical energy. More research will lead to the development of new, efficient solar energy harvesting technologies based on the natural process.
  3. Fiber / materials: Wood is an important material for building and many other purposes. Paper, for example, is nearly pure photosynthetically produced cellulose, as is cotton and many other natural fibers. Even wool production depends on photosynthetically-derived energy. In fact, all plant and animal products including many medicines and drugs require energy to produce, and that energy comes ultimately from sunlight via photosynthesis. Many of our other materials needs are filled by plastics and synthetic fibers which are produced from petroleum, and are thus also photosynthetic in origin. Even much of our metal refining depends on coal or other photosynthetic products. One of the carbohydrates resulting from photosynthesis is cellulose, which makes up the bulk of dry wood and other plant material. When we burn wood, we convert the cellulose back to carbon dioxide and release the stored energy as heat. In developing countries, firewood continues to be critical to survival. Ethanol (grain alcohol), produced from sugars and starches by fermentation, is a major automobile fuel in Brazil, and is added to gasoline in some parts of the United States to help reduce emissions of harmful pollutants. Our major sources of energy, of course, are coal, oil and natural gas. These materials are all derived from ancient plants and animals, and the energy stored within them is chemical energy that originally came from sunlight through photosynthesis. Thus, most of the energy we use today was originally solar energy!
  4. Environment: Plants remove carbon dioxide from the atmosphere and replace it with oxygen. Thus, they tend to ameliorate the effects of carbon dioxide released by the burning of fossil fuels. The artificial photosynthetic reaction centers produce energy without releasing any byproducts other than heat. They hold the promise of producing clean energy in the form of electricity or hydrogen fuel without pollution. Implementation of such solar energy harvesting devices would prevent pollution at the source, which is certainly the most efficient approach to control.
  5. Agriculture: Because plants depend upon photosynthesis for their survival, interfering with photosynthesis can kill the plant. This is the basis of several important herbicides, which act by preventing certain important steps of photosynthesis. Understanding the details of photosynthesis can lead to the design of new, extremely selective herbicides and plant growth regulators that have the potential of being environmentally safe (especially to animal life, which does not carry out photosynthesis). Indeed, it is possible to develop new crop plants that are immune to specific herbicides, and to achieve weed control specific to one crop species.
  6. Electronics: Learning how plants absorb light, control the movement of the resulting energy to reaction centers, and convert the light energy to electrical, and finally chemical energy can help us understand how to make molecular-scale computers.
  7. Medicine: Because plants and other photosynthetic species have been dealing with light for eons, they have had to develop photo-protective mechanisms to limit light damage. Learning about the causes of light- induced tissue damage and the details of the natural photo-protective mechanisms can help us can find ways to adapt these processes for the benefit of humanity. Research into the nature of photosynthesis is crucial because only by understanding photosynthesis can we control it, and harness its principles for the betterment of mankind.

Evaluation of the poster boards.

Each group will present their models of the mechanism by which Qs obtain their energy. They will follow guidelines in Handout 2. Their work will be evaluated by their peers according to the assessment table (Handout 1). Each group will have 15 minutes to present their models and answer any questions. The poster board presentations will continue into and throughout lesson 5.3. At the end of the lesson 5.3 collect and grade the assessment tables.

ASSESSMENT

First part of this lesson is a discussion, therefore most of the lesson is note taking and talking. You can evaluate students based on their participation. In the second part of the lesson, the poster board presentation, each group can be evaluated for their efforts of creating the model and depicting it. You will also collect the assessment tables. At the end of the unit you will give students a comprehensive exam 40 minute. It will test student understanding of the material and the aspects of Nature of Science covered in this section.

HANDOUTS

Lesson 5.2 Handout 1.

Name: Assessment Table

ModelGroup 1Group 2Group 3Group 4Group 5Group 6
Is the model based on observations?YES/NOYES/NOYES/NOYES/NOYES/NOYES/NO
If yes, list them
Can the model predict Qs behavior?YES/NOYES/NOYES/NOYES/NOYES/NOYES/NO
Give example
Is this model as simple as possible?YES/NOYES/NOYES/NOYES/NOYES/NOYES/NO
Why?
What are the limitations of this model?
Poster BoardGroup 1Group 2Group 3Group 4Group 5Group 6
Are all the elements of the model clearly depicted?YES/NOYES/NOYES/NOYES/NOYES/NOYES/NO
If not, explain
Are all the elements clearly labeled?YES/NOYES/NOYES/NOYES/NOYES/NOYES/NO
If not, explain


Lesson 5.2 Handout 2.

Make sure to present:

  1. Model of the mechanism through which Qs obtain energy
  2. Supporting Evidence with your reasoning.
  3. The revisions you incorporated after learning about photosynthesis and the reasons you felt they were necessary.

Final Test

Name:

Date:


Photosynthesis


1. Photosynthesis in plants results in the production of: a) Glucose b) Protein c) Oxygen d) Nitrogen

2. What are the two major stages of photosynthesis in plants called? a) Light-dependent reactions b) Light-independent reactions c) Chlorophyll reactions d) A and B

3. How is the chloroplast arranged? a) Two outer membranes wrapped around the stroma containing the grana b) An outer membrane wrapped around the thylakoid membrane containing the stroma c) An inner membrane wrapped around the grana containing stroma d) An inner membrane known as the thylakoid membrane extanding through the stroma

4. In the light-dependent reactions of photosynthesis in plants: a) ATP is synthesized b) Sunlight is captured by the chloroplasts c) Water molecules are split d) NADPH is formed

5. In the light-independent reactions of photosynthesis in plants: a) Carbon dioxide is used as a carbon source b) Glucose is formed c) NADPH is formed d) Water is split

6. When a leaf is green it means that chlorophyll is the only phototsynthetic pigment in use. a) True b) False 7. Energy can be recycled through an ecosystem many times. a) True b) False Short Essay Questions:


1. How does energy relate to food? ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


2. List 5 examples of different energy types. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


3. What are scientific models? Why do scientists use them? ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

4. List 5 reasons we study photosynthesis. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Around Wikia’s network

Random wikia