1. Given the challenge and the performance of your car on Test Drive #1, what change(s) did you make for Test Drive #2? We made our racer bigger and heavier with a longer rubber band.

2. What differences did you predict these changes would make in your cars performance? What makes you think this? I thought that it would go farther and roll farther because the extra weight will not do anything on the ground.

3. Think about the variables such as the size of the spool, weight of the washer or tension of the rubber band. How might these affect how far or how fast your car will go? The spool size meant nothing because it didn’t spin, we did not use a washer, and the rubber band tension made the elastic energy push it farther with more elastic energy.

4. What worked better the second time? The car went 425 inches in 1.8 seconds which is 232.24 inches per second. Which transfers to about 13.2 mph. All of these are twice as good as last time.

5. What still is not quite working? Breaking the sound barrier.

6. What questions do I have? None.

7. What might I try next? Make a bigger racer.

8. Explain the energy transfer that is taking place in the racer. We stretch the rubber band and when we let go the heavier side shoots forward and launches the racer.