Day 6: Thermoelectric Cooler and Otto Cycle

Thermoelectric Cooler

At the beginning of the class, we did an experiment on peltier cooler which one side is put in hot water and other side is put in cold water and the disk would start to rotate.

If we reverse the order of the hot and cold water, the direction of disk's rotation would reverse also.

Then we attached a power supply to the leads on the cooler, one side of the cooler got hot while the other side got cold.

Molar Heat Capacity for an Ideal Gas

Then, we used the formula C =Q/ΔT and Cmolar = (1/n)(Q/ΔT) and ΔEint to get the formla Cp = 5/2 R

Does = P-V^g = Constant for an Adiabatic Expansion?

We used to the equations in the photos to calculate the relationship between  ΔP and P = -(CpΔV)/(Cv*V)

We integrate the equatin dP/P + (Cp/Cv)(dV/V) = 0 to calculate that T_fV_f^g–1 = T_iV_i^g–1

Work in an Adiabatic Expansion

We did an activity about work in an Adiabatic expansion, calculating the work in adiabatic process, and got 1246 J as work.

The Carnot Engine Cycle

We started to learn the Carnot engine cycle, which we calculated the Eint, W, Qh, and efficiency for a cycle.

To increase efficiency of a car, we need a cool radiator and a hot engine, which Th has to be a lot larger than Tc.

Otto Cycle

In these photos, the Otto cycle was introduced.

The three ways to increase power of engine are to increase the revolutions, increase the volume of engine, and increase maximum pressure. 

Conclusion

In today's class, we first learned about thermoelectric cooler, then we learned the molar heat capacity. We also learned that the adiabatic change in PV diagrams and work in adiabatic expansion, finally we learned about Carnot cycle and Otto cycle, and discussed about how to increase the power of an engine.