First Law of T-D, Kinetic Energy, and Cylinder Spark

Today we worked with the concepts of Kinetic Energy and the First Law of Thermodynamics.

1. First Law of Thermodynamics

In the above picture, we were conveying the relationship between the work someone does, the heat they acquire, and the energy they use.
                   

 Here we expressed work in terms of the pressure and volume change, instead of force and distance that force moves the object.

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Here we demonstrated the equation "energy change equals the heat absorbed minus the work performed". The bar is heated, so it absorbs heat. Also it expands in size, which equates to positive work. The difference between these two is the internal energy change of the object, which is positive in this case.

2. Kinetic Energy

Above we used the relationship between kinetic energy and temperature to rewrite pressure in terms of kinetic energy, number of molecules, and volume.

3. Cylinder Spark

Here we used the ideal gas law, pv = nrt to figure out if a material placed inside a cylinder would ignite. We could ignore the moles of air and R, since those are the same in the initial and final states of the cylinder. By measuring the initial and final volume as well as the initial temperature,we predicted that the temperature would be enough to cause ignition, which it did.