# Verification of Joule's Law (Heat produced is proportional to current squared)

When a current flows through a heating element which is immersed in water in a calorimeter the temperature of the water rises. In this experiment we investigate how the temperature of the water and calorimeter change with the current flowing through the heating element. Note: In the lab. this is a very time consuming experiment as each different current must be allowed to flow for at least 5 minutes. In this simulation 90 seconds is sufficient for each current.

Procedure:
1. Use the slider to set the current value to 0.5 A.

2. Note the starting temperature and current and record in a table.

3. Press "Close Circuit". Current begins to flow in the heating coil and the timer starts. Note: A very small rise in temperature occurs when the current is at 0.5 and 1A.

4. After 90s, press "Open Circuit". Record the rise in temperature.

5. Press "Reset" and again use the slider to set the current to 1 A. Record the starting temperature and current.

6. Repeat steps 3 to 5 until at least six readings have been taken.

Analysis:
Draw a graph, on graph paper, of Rise in Temperature versus Current squared. Start both axes at zero and draw a "best fit" line through the data points.

Precautions:

• Ensure that the current remains constant at each value. Adjust the variable resistor if necessary.
• Ensure that the heating coil is completely covered with water to avoid heat loss as measured by the thermometer.
• Use a well insulated container.
• Stir before taking temperature readings and take the highest value observed.

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