Heating with a battery
You may have found that it's a lot of work to generate even a little bit of heat! Now you will compare the heating you did with the Genecon to the heating a little battery can do. Connect the Temperature probe to your handheld computer. Refer to Technical Hints to connect the Temperature probe.
Locate the parts for your small " heat cell" which consists of a resistor inside a block of aluminum. When you put electrical current through the resistor, it converts the electrical energy into heat and heats up the block of aluminum. The heat cell is placed in insulation to prevent heat loss to the environment.
Insert the tip of the Temperature probe into the small hole in one end of the heat cell. Put on the insulation cover and close the box with a rubber band.
Use a 2-AA battery pack, which will supply somewhat less than 3 volts, to warm the heat cell. You can use the battery pack on the air cart for this. Attach one of the battery leads, but not the other, to the heat cell.
Start the software for the Temperature probe. Refer to Technical Hints to see how to use the software.
When the temperature graph reaches exactly 10 seconds, connect the second lead of the battery pack to the other end of the heat cell.
Heat the cell for 60 seconds, then disconnect one battery lead. Let the graph run another 60 seconds so that you can watch the cooling of the heat cell.
Stop recording the data. Save the data to your handheld computer.
Expand the graph so that you can see how much the temperature rose while the battery was attached and how much it decreased after you stopped. Place marks on the starting temperature, the maximum temperature, and the ending temperature. Record these values in Notes:
the starting temperature
the maximum temperature
the ending temperature
Calculate these values in Notes:
temperature change from start to maximum
temperature change by cooling
Was each temperature rate over time steady?
The heat cell is made so that it takes exactly 10 joules of energy to heat it one degree Celsius. How many joules of heating did the battery produce in 60 seconds? How many joules did the cell lose in 60 seconds? Record your answers in Notes on your handheld computer.
