Thermoelectric Cooler, Incredible Mass Lifter, Ideal Heat Engine Gas Cycle

Thermoelectric Cooler

hypnotic circle

Hot water was poured into one cup and cold water is poured into another cup.  The thermoelectric cooler has two metal sides that stick out of it like a tuning fork and one side is placed into the hot water and the other is placed into the cold water.  The temperature of the hot and cold water stay relatively constant so it can be said that the change in temperature is 0.  Because the temperature stays relatively constant, then it can be seen that the change in heat transfer will equal work.  So as the heat begins to transfer from the hot water to the cold water, it generates work and the hypnotic circle begins to spin.  If you were to turn the thermoelectric cooler around and now have the metal side that was in the hot water now be in the cold water and the metal side that was in the cold water now be in the hot, then the hypnotic circle should begin to spin the opposite direction meaning that this is an example of a reversible heat engine. 

Moving Hypnotic Circle

Hypnotic Circle Attached to Power Source

Next we attached a power source directly to the hypnotic circle without it being placed in any water and it began to spin.  After having this system spin for a minute, it could be observed that there was a heat transfer between the two metal feet at the bottom of the thermoelectric cooler.  This is because the temperature never really changes to the work done on the object is equal to the change in heat transfer.  So the work that was being generated allowed for heat transfer between the two metal poles.  

Incredible Mass Lifter Set-up

Incredible Mass Lifter

We began this experiment with two different cups of water, one hot one cold, a flask with a plunger on the top and a frictionless piston that is attached to the flask/plunger and also to a pressure sensor so the pressures can be recorded.  We found the initial volume of the system and recorded that and then placed the 84 gram weight on top of the piston while the flask was placed into the cold water.  As the weight is placed on the piston, the volume goes down lowering the mass and the pressure goes up which can be seen as an isothermal process because the temperature of the cold water stayed the same.  Next, the flask is moved from the cold water to the hot water, so the temperature goes up and the volume goes up, raising the mass, which makes this an isobaric process because the pressure remained the same.  After the mass was raised, it was removed which increased the volume and decreased the pressure of the system which made this process isothermal because the flask stayed in the hot water.  After the piston moved up from removing the mass, the flask was then placed back into the bath of cold water which decreased the temperature and volume of the system, returning the piston to its original position, while the pressure remained the same which made it an isobaric process.  

After the whole four step process was completed, a square type shape was shown on a position vs volume graph that was made with logger pro.  It can be seen that the area under a pressure vs volume graph is the sum of the work done, so before retrieving the actual work done from logger pro, we first calculated it with triangles and squares drawn within the curve.  I calculaculated the area under the curve to be 25.599 cc/kPa which, after rounding up, is identical to the logger pro value which was 26 cc/kPa.

Ideal Heat Engine Gas Cycle

Explaining intake/compression strokes

This Heat Engine is a four stroke process.  It goes through an intake/exhaust stroke, compression stroke, an ignition stroke, and an expansion stroke.  First, in the intake stroke, the valve opens as the piston goes down.  When the piston is in the process of going down, it is creating a vacuum so that fresh air and fuel can be pulled in by the open valve.  In this step, the volume and number of moles are changing making this an isobaric process.  Next, in the compression stroke, the valves are closed so as the piston moves up the volume and pressure are changing rapidly making an adiabatic compression of gas fuel mixture in the cylinder.  After, the ignition stroke takes place and the air fuel mixture rapidly ignites at top of the compression stroke while the volume is essentially constant making this part of the process an isochoric one.  From the extreme increase in pressure, the piston gets pushed down and the expansion stroke takes place.  This is another adiabatic process because the volume is being increased which in turn decreases the pressure, this the part of the cycle that does positive work.