In this lab we discussed how different situations are affected by the addition of heat or the energy present. A demo with a rubber band doing work by lifting cans up and down by allowing the rubber to expand and contract by using a heat gun. Also finding and defining the use of thermal efficiency to determine the net work done in a system by using n. However the main purpose of the lab was the different heat engines using the gas cycles to operate by solving them in different points of the cycle and their transition points. Then finding the work done in a PV graph using the integration method even though some may not have a defined shape in heat engines.
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| This is the set up for the experiment or demo of the rubber band being able to expand and contract when heat is applied although the experiment did not work because it was not rubber we came to conclusion that it works like a heat engine because it does work at certain times of the process when placed in hot and cold situations. |
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| The pic reveals the prediction of our group when it came to the demo of the rubber band using heat to lift cans up and down using our explanation in the picture to describe each step of the system. |
We analyzed a heat engine using the gas law to work doing a scenario in the lab manual. By developing a PV graph we were able to calculate the work and energy done in the system by using the points and transitions to see what kind of heat engine used. The engines use the gases like isobaric, isochoric, isothermal and adiabatic process in the steps to be able to operate by the work done.
A PV diagram prediction of the situation described in the lab notebook using the gas laws to move from point to point and each one has its certain transition like a constant pressure and constant volume.
This is the same PV diagram from above but this one has all the calculated problems and questions from the notebook where we able to find the work, het energy, internal energy and the total change in that energy using the points and transition points as well.
We know that Eint = 3/2nRT so we were able to apply to each of the points to find the values to find the total which were: E1=3060J, E2=-3450J, E3=-2730J, and E4=2760 J and also we used the different properties of each situation like isobaric and adiabatic to find the work and energy at the transition points. In the end the result was the net Work for the whole engine process in which all the work is added to each other resulting 460 Joules.
The second part of the lab was the mass lifting syringe were a mass is used on a syringe to find the work done by the engine cycle. We have done this lab prior to this lab showing that when the flask is in the cold water the plunger drops and when placed in the hot water the plunger rises from the initial volume to a higher point. In this case we do the experiment and make A PV diagram to find the values like in a gas cycles.
This is a prediction done by the group what we expected the graph to look using the situation in the book and using our prior knowledge of the experiment to make a reasonable prediction of the cycle.
The experiment set up in order to find the work done by the syringe or system when the flask closed with an amount of air in different temperature baths to move the syringe up or down to see the amount of work in the system.
After doing the experiment the data was recorded to show this PV graph revealing that our graph was a bit off due to the flat points of our lab. In this graph it shows that there is no constant pressure or flat interval in the graph and that is what the actual graph result is to find the calculated values properly.
The last part of the lab was doing Active Physics pertaining to the heat capacity, describing and showing different scenarios using the demo. Each of the activities had it questions in order to understand what is being done and at the end combining all of them to be able to make a conclusion of finding C which is the value 5/2R.
This a screenshot of the activity to show the different ways a person can use this to answer the questions in the lab notebook to find the heat, heat capacity and the temperature changing. When doing all the of the activities we were able to make a relationship between all of them to do question 8 to find 5/2R.
This is the Carnot cycle with a given PV diagram and like the one before being able to use the gas laws on the points and transition points to find each of the values need to show like work and internal energy of the cycle process.
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