Thermal expansion, heat, and phase changes

1. Thermal Expansion: We explored the concept of Thermal Expansion, which explains how material expands due to heat.

Here we had a strip made of two different metals on each side. The equation for linear thermal expansion is deltaL = aL(initial) (deltat). DeltaL is the change in length, a is the coefficient of thermal expansion (size increase/temp change), and deltat is temperature change. Since one metal had a lesser value of a, we correctly predicted that the strip would curve over the metal with the lesser value. This is because the length of the opposing metal is growing quicker.

In this setup, we heated the steel tube from the inside, causing it to expand. The expansion caused a wheel at the end to turn about its' center. We used the relationship between linear and angular quantities to express our coefficient of thermal expansion in terms of the circle's radius, the angle the wheel moved, the temperature and initial length of the tube

2. Heat and Phase Changes: Here we placed a heater in water/ice so we can work with the concept of heat and phase changes.

 This was our procedure to the experiment, which was to mix an equal amount of water and ice and heat it to melt the ice, and all the way up until it boils.

 Here is the setup, at this step the ice has been added and we are heating up the mixture while stirring

 

In the above two sheets, post-lab questions have been answered. They were mainly answered with two equations: Q=mct and Q=mL. Q stands for heat, m for mass, C for the heat capacity of water or ice, t for the temperature change, and L for the Latent heat of fusion or vaporization. Additionally, I also found Q by multiplying wattage of the heater (J/s) by however long the time frame (s) required.