Linear Thermal Expansion

This is what we did in Physics 4B on Thursday August 28th, 2014.

Linear Thermal Expansion:

We first told to predict what would happen to a metal ring if it was held over a fire. Would the metal ball be able to go through then? The answer was yes.

These are the formulas for linear thermal expansion in two dimensions.

We were told to predict which side the bi-metal strip would curve to if put over a fire. This bi-metal strip was composed of Invar and brass. My lab group and I predicted it would curve into the Invar because the brass would expand a lot faster than the Invar would.

These are clips of Professor Mason conducting the experiment.

My lab group and I predicted correctly. He also put the bi-metal strip inside a box of ice and asked us which way the strip would curve to then.

My lab group and I predicted right again. The brass shrunk faster than the Invar side and thus the bi-metal strip curved into the brass.

This graph represents a bar of aluminum being expanded by hot water vapor.

We were then asked to find the change in length using the given information.

This is a graph of water's phase change from ice to vapor.

The class was then asked to identify five different states of matter. My lab group and I knew one through four but we did not know that a Bose-Einstein Condensate existed, which is the fifth state of matter.

Our last lab was to determine the latent heat of fusion of ice and the latent heat of vaporization for water. This was my lab group's plan on how to determine them as accurately as possible.

We used instruments such as the power meter (shown below), temperature probes, the Logger Pro program, Styrofoam cups, paper towels, and an electronic scale in this lab.

This was our mathematical work when we were trying to determine what the mass of water was in a given problem by Professor Mason.

Below are some clips and pictures of what we did during the lab as well as a final graph of our lab.

Our water and ice weighed 104.2 grams; and thus the final mass was 209.6 grams. The power of the immersion heater was 283.2 W at most times. It took the ice 100 seconds and 28,320 J to start melting. Thus, our latent heat of fusion of water was 270.2 J/g; however, the accepted value for that was 334 and out percent discrepancy was 19%. Similarly, we found our specific heat of water value to be 5.172 and our percent discrepancy was 36%. We found our major source of error was the fact that we used a ceramic mug to conduct the actual experiment in which the mug absorbed a lot of the heat energy.

At the end, we allowed our water to boil for a minute. We calculated the grams of water that turned to steam to be 12.7 grams. Thus, our latent heat of vaporization of water was 2229.9 J/g with a 1% discrepancy.