Lab 5: Heat

  There are four state variables can influence thermodynamic state:

  These are the answers for the lab manual questions. First graph is Isobaric process, second graph is Isochoric process, and third graph is Isothermal process.

  These are example problems for us to solve by using the processes that list above.

  Professor gave us four graphs and wanted us to match the graphs and the processes. Isothermal process graph and Adiabatic process graph are very similar but Isothermal process graph  is gradual change of volume and Adiabatic process graph is sudden change of volume.

  Now we know a rubber band will shrink because heating after we watch a rubber band heating video on  youtube.

  These are the steps for can lifter cycle.

  The engine will not work if environmental temperature and heat gun temperature are the same. Also, not all heat will transfer to work. Some will escape to environment.

  This is the equation we found for thermal efficiency.

  This is an example problem for us to do about the cycle. First, we found out internal energy by using the equation E_int=(3/2)P*V. Second, we found out △E by using p2-p1, p3-p2, p4-p3 and p1-p4. Last, we need to found out net work and net heat. It was easy for us to calculate work because we can use the equation W=P△V. Now, we knew work and △E, so we could calculate heat by using  Q=△E+W. Then we just add them up to found the net work and net heat.

  Last, we did the mass lifter heat engine experiment. 

  First, we collected four different volume and pressure by using the pressure sensor. Then we used E=(3/2)PV to find the internal energy. Last, we found the mass and heat for each process.

  In conclusion, there are three important processes need us to remember; Isobaric process - pressure is constant; Isochoric process - volume is constant; Isothermal process - temperature is constant. The can lifter cycle experiment is very interesting. We could find internal energy by using E_int=(3/2)P*V and find △E by subtract each process.