Conservation of energy: Banana leaf marble ramp

Does conservation of energy theory predict the marble speed?

Materials

• banana leaf
• marble
• meter sticks
• stopwatch

Procedure

1. Measure the vertical height of the marble above the table top surface.
2. Measure the velocity on the table for the marble. Start the stopwatch when the marble reaches the bottom of the ramp, stop the stopwatch when the marble reaches the end of the meter stick. The distance over which you time may need to increase as the speed increases.
3. Sketch a graph of your actual velocity data.
4. Does the data appear to be linear?
5. The instructor will derive the energy theory prediction data.

Energy

Energy can exist in different forms. For the banana leaf marble ramp there are two forms of energy. At the start the marble possesses gravitational potential energy. The amount of gravitational potential energy is directly proportional to the height h of the marble above the table. After the marble is rolling on the flat surface of the table, the marble has only the energy of motion, called kinetic energy.

Conservation of Energy

The theory that energy cannot be created nor destroyed is called conservation of energy. The word conservation is used in the physical sciences to mean "stays the same" and "no change." All of the gravitational potential energy of height must be present in the energy of the motion of the marble once the marble reaches the table.

Lab report turn-in: Table with labels, units. Graph with labels, units, both the actual and energy theory data on the same graph. A linear trend line will not fit, do not add a linear trend line. Discuss whether the "shape" of the curve produced by your data matches or does not match the "shape" of the curve produced by the energy theory prediction.