# Dtse2007:ALG 06 Work and Energy - Morgan& Charles& Katy

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## Technology in our Stuff

Video tape observational experiment. Upload it onto a computer, so the class can watch it together. We are also considering using active physics simulations for our testing experiments.

## NJ Standards

## Prerequisites

- Basic algebraic skills
- An understanding that forces arise from objects interacting
- An understanding that forces cause an object's motion to change===
- Ability to draw a free-body diagram
- Ability to draw a motion diagram

## Goals of Unit

### Conceptual

- Students should be able to identify a system
- Students should be able to identify the initial and final states of a physical process
- Understand the concept of work and how it relates to dynamics
- Learn about different kinds of energy
- Be able to describe the different types of energy mathematically
- Understand how energy transforms in a system
- Understand how a change in a system's energy is caused by interactions with external objects

### Quantitative

- Students should be able to construct energy bar charts
- Students should be able to develop equations from the information on energy bar charts
- Students should be able to construct the mathematical relationship between force and displacement for work
- Students should be able to construct the total work-energy equation

### Procedural

- Students should be able to develop testing experiments for the relationship between different physical quantities
- Students should be able to evaluate the effects of assumptions on the predicted outcome of experiments
- Students should be able to describe a mechanical process using multiple representations: words, pictures, energy bar charts, and mathematical equations
- Students should be able to apply these situations to real life situations

### Epistemological

### Relationships to other units

- Relates to kinetics, dynamics, and motion

### Other

- Only external forces do work on a system.
- Internal interactions lead to changes in different types of energy inside the system.
- If Earth is included in the system, the gravitational force does not do work on objects inside the system.
- We include surfaces of rubbing objects in the system. Their motion leads to changes in internal energy.

## Most Important Subject Matter Ideas

## Student Difficulties

- Recognizing the different types of energy that a system can have
- Recognizing that there are multiple ways to represent information

## Relevance to Student's Lives

## Text and Other Materials

## Lab

## Assessment

### Traditional

Experiment that help students devise the new concept of work. Two crucial ideas: What is a system? What is a process? Students observe experiments during which they focus on process involving a carefully chosen system. They try to decide what was done to the system by a force exerted by an object outside the system. Because this is an external force, the system objects acquire the potential to do something--for example, to break a piece of chalk. Students develop a definition of work through small refining steps. Activities try to decide what quantities were involved in giving the system the new potential to break chalk and how these quantities are related. Activity where students come up with a definition of work (W=Fd). Students perform activities to test this definition. Activity where students realize that work and be positive or negative. 6.1.4 helps students visualize how different quantities affect work. Activity where students come up with the names for energies (Gravitational potential energy, kinetic energy, elastic potential energy, and internal energy. Students should structure these ideas on their own. They should then be given the common terms for their ideas.

### Alternative summative assessment

### Student Projects

### Activities out of Classroom

===Modifications for different learners Equipment References Reflection