1. MARBLE EXPERIMENT, PART 1

2. PE = potential energy KE – kinetic energy

3. 1. The cotton allowed the marble to roll the fastest, because it was so smooth. There was very little friction to use up the KE.

4. 2. The fleece caused the marble to roll the slowest because it was thick and had fibers on it that held onto the marble, making it lose KE.

5. 3. A heavier marble would roll faster because it had more weight (and so more “momentum”). If it rolled faster from the start, it would also roll further out onto the fabric.

6. 4. It started with no KE (because it was at rest, speed 0). All of its energy was GRAVITATIONAL PE to start with. By the time it got to the start of the fabric, its energy was all KINETIC ENERGY, because it was going the fastest speed.

7. 5. When the marble started rolling onto the fabric, it had all KE. Friction caused it to lose energy, as HEAT energy. It had zero KE when it stopped (speed of 0), and all the energy was lost as HEAT energy.