Overview

Students continue working on their wind-ups, recording the issues that come up.  They are introduced to the concepts of "potential energy", "elastic energy", and "kinetic energy." 

Advance Preparation

• Select a book or video that introduces energy.
• Prepare chart paper to post issues that arise in making wind-ups.

Materials

• Partially completed wind-ups from Lesson 1
• Materials for making wind-ups, for use as spare parts.

Procedure

1. Wind-up issues and energy: In a class meeting discuss the issues students have encountered. They are to keep track of these issues. Introduce the concepts of potential energy, elastic energy, and kinetic energy, connecting them to the wind-up:

• When I wind the stick, I move. This moving is kinetic energy. Where does my energy go?
• It goes into twisting the rubber band, where it is stored as elastic energy. Elastic energy is potential energy. It is ready to make something move.
• What happens to the potential energy stored in the rubber band, when I let the wind-up go? 
• The potential energy in the rubber band is used up making the wind-up go. Potential energy is changed into the energy of motion: kinetic energy.

If available, show a video or read a book on the different forms of energy

2. Making wind-ups: Students continue working on their wind-ups. Students who have already made wind-ups can help others and/or make new ones of different types. As students are working, ask them to keep track of issues that arise. Post the issues on chart paper. As students ask for help with problems, identify these as issues, by adding them to the chart. Some examples of issues that are likely to come up:

• The rubber band won’t go through the holes.
• The wind-up won’t stay together.
• The wind-up does nothing at all.
• The wind-up moves but won’t go in a straight line.
• The wind-up moves, but spins in place instead of traveling
• I would like the wind-up to go farther
• I would like the wind-up to go faster

3. Science Notebook:

• Compile an Issues List, including anything that didn’t work the way you wanted it to.  
• Describe what you did today.

4. Outcomes

• Students learn to isolate problems. You can’t usually solve a problem until you know what it is. 
• Word wall words:  potential energy, elastic energy, kinetic energy, issues.

Troubleshooting

1. The rubber band won’t go through the holes.
2. The wind-up won’t stay together.
3. The wind-up doesn't move, but

• The stick turns and the paper clip stays still.
• The stick and the paper clip turn.

4. Nothing turns: stick, paper clip or wind-up.
5. The wind-up moves but won’t go in a straight line.
6. The wind-up spins out: rubber band too thick or wheels too small.
7. The wind-up doesn't go very fast.