Mechanical Equivalence of Heat

- Two large styrofoam soup cups
- Thermometer
- Dense metal (lead shot or fishing weights, coins)
- Cardboard tube at least 2 feet long (to act as guide and measure for the drop)
*The drop should be as long as possible. If you can construct a tube that will support a drop of two to three meters, your noticeable heat change will be more reliable.* - Water

- Fill one styrofoam cup with water, but leave room to add weights.
- Add a measured amount of water to the second styrofoam cup (do not fill more than half full).
- Measure and record the temperature of the water.
- Measure the mass of the weights you will drop.
- Place in the first styrofoam cup and allow weights and water to come to room temperature.
- Assemble the tube above the second styrofoam cup to act as a guide for the drop. Make sure all the weights will fall into the cup.
- Take the temperature of the water in the second cup.
- Remove the weights from their water bath and drop them into the second cup using the tube as a guide. Record the amount of mass dropped and the distance they fall.
- Measure the temperature of the water (including the weights).
- Repeat your procedure several times.

- Determine an appropriate table layout to record distance for fall, volume of water and its mass, mass of the weights dropped, starting and final temperature of water in second cup.
- Add columns to calculate temperature difference and calculate the amount of heat required to raise the measured amount of water by the temperature difference using q = mC * ΔT.
- Determine the potential energy change of the dropped mass using PE = mgh.
- Compare the mechanical energy change (PE) and the heat energy change.

- Use the guidelines for lab reports to prepare a formal report of your work.

Post your report to the Lab thread at the Moodle.

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