Wednesday, February 26, 2014

Immersion Heater Experiment

In this experiment, immersion heater is used to heat up water in a paper cup and the temperature changes were measured and recorded.

The actual output of the immersion heater is 297 Watts, which was measured using the Wattmeter. If the heater is run for twenty seaconds (which is the case in the experiment), the heat generated is 5940J. This is calculated by multiplying the heat output with the amount of time the heater run. 


This is the heat vs. temperature graph with the heat calculated from the temperatures recorded.

The relationship between the heat and temperature is linear. The slope of the graph is the heat capacity of water. If the mass of water is cut by half, the slope will stay around the same even though the mass is part of the calculation of the slope. Thus, the heat capacity (slope) is independent of the mass.

The equation is

Thermal Conductivity of Aluminum

 In this experiment, an aluminum can, hot water, cold water, and Styrofoam cup were used. Hot water was put inside the aluminum can which was then immersed into the cold water in the Styrofoam cup.

As soon as the aluminum can is immersed, the temperature outside and inside of the can are measured and recorded. Below is the graph of heat vs. time. Heat was calculated from the recorded temperature.

Then, the cross sectional area of the can was calculated.
The surface area was calculated and it is equal to the area of the circle of the bottom of the can and the area of the rectangle that makes up the cylinder. 

Then, the thermal conductivity of aluminum was calculated.
Both k values are not closed to the actual thermal conductivity of aluminum. It would seem that this is not the right way to calculate the thermal conductivity of aluminum. However, I do not know the correct way and this is my best guess. I understand this is inexcusable, but I do not have anything more.