Galileo's Pendulum: Testing Experiment

Aim

To test the concept of energy conservation.

Prior Knowledge

The concept of a system, the concept of gravitational and kinetic energy, energy transformation, and energy conservation.

Description of the Experiment

Luis will release the pendulum bob at a specific height and let it swing freely. Then he will place an obstacle in the way of the bob and repeat the experiment releasing the bob at the same height as before. Define your system of analysis and use it to predict how high the bob will rise this time. Then repeat your prediction for the new height of the obstacle. Continue making the prediction for the changing height of the obstacle. What is the lowest possible position of the obstacle? What motion of the pendulum will occur then?

Addtional Information

If you are familiar with work-energy bar charts, use a bar chart for your prediction.

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Questions

• What changes occur to the pendulum motion during the experiment?
• How is this experiment different from the first observational experiment with the pendulum?
• What were the unexpected features of the experiment that made you rethink your model?
• Did you include the string in the system? If not, did it do work on the system?