Inverse Curve Fit and Gas Laws (3rd Day)

Spring 2015
Professor Mason
March, 3rd

Pressure and Volume Change of Water in Can

This morning, we did an experiment which involved a can filled with hot boiling water and a beaker filled with cold water. The experiment was to place the can upside down into the cold water and see how it would react. The result was the water inside the can rapidly imploded due to extreme difference in temperature; therefore, the can was crushed.

Then, after we did the experiment with the can filled with boiling water, we did another experiment. This experiment involves a heated empty can (only filled with air). The process was the same; we, as well, place the heated empty can upside down into the cold water. The result was nothing happened to the can; however, the cold water was pulled into the can after a few seconds.  It looks like this:

Ideal Gas Law
In class, professor Mason set up three beaker glass: one filled with cold water, one filled with hot water, and the other one was filled with room temperature water. The first graph was Pressure (kPa) vs Temperature (C), which is linear fit.

There is also an experiment which involves the no friction syringe. The graph looks similar to Pressure vs Temperature graph, which is linear fit.

An ideal gas can be divided by three variables: pressure (P), volume (V), and temperature (T). The calculations for Ideal Gas Law are:
PV = nRT = NkT
n = number of moles
R = universal gas constant = 8.3145 J/mol K
N = number of molecules
k = Boltzmann constant = 1.38066 x 10e^-23 J/K = 8.617385 x 10e^-5 eV/K
k = R/NA
NA = Avogadro's number = 6.0221 x 10e^23 /mol

Other than PV = nRT = NkT formula, there is also a formula which include [(P1*V1)/T1 = (P2*V2)/T2].  These are the examples we did in class.

The other form of ideal gas law is the statistical mechanics. P = n*Kb*T. P is the absolute pressure of the gas measured in pascals, n is the number density in the gas measured in 1/(meters cubed), Kb is the Boltzmann constant relating temperature and energy, and T is the absolute temperature. The number density can also be applied to the other formula, which uses N, the number of moles and V, the volume, which leads to R = Na*Kb where Na is Avogadro's constant.












Pressure vs Volume

In class, we did an experiment of Pressure vs Volume, which involves a tool that can manipulate the pressure inside the glass. The pictures and videos above are the examples of our experiment. First off, we started with the balloon; we put the balloon inside the glass and started with taking out all the pressure inside the glass. As a result, the balloon inflated because there is no pressure that kept the balloon from inflating. On the other hand, when we put the pressure back in, the balloon deflated because there is pressure that keeps the balloon from getting bigger. A simple example is like sponge being crushed by hand; it means that the sponge is receiving pressure from outside.

After we finished experimenting with the balloon, we did the next one which was marshmallows. It works almost the same like balloons did. The marshmallow went bigger when the pressure inside the glass was taken out. However, the difference is when the marshmallows is receiving the pressures back; it does not return back to normal like the balloon did, but it got smaller than the original ones.

Boyle's Law (syringe)
Another experiment that we also did in class was Boyle's law, which involves a syringe, Logger Pro, and pressure sensor. The goal of this experiment is to obtain measurements by trapping a volume of air in the syringe and then compress the air slowly to smaller volumes by pushing the plunger. This is how we set up on Logger Pro.

After we set it up on logger pro, we pressed collect in order to know how to graph will look like by pushing the plunger slowly after we pressed the collect button. These pictures below are how the graph look like.

We also made a prediction of these graph  beforehand; and this is how the prediction looks like before we did it on logger pro.