Saturday, March 7, 2015

Pressure vs. Temperature and Volume



The picture above shows what we thought would happen if a heated can was introduced to a container of cold water. We assumed it would implode since the little water inside the can would expand with heat, but would rapidly shrink once placed in the ice water.

The video above shows what happens when a heated can is dropped into a beaker of cold water, it implodes.


We assumed that the experiment would run similarly when the can was placed top end down, just to a lesser extent.


The video above shows what happens when a similar can is placed top end down into a beaker of cold water. Since the can was heated, the the volume of air was displaced out of the top, when placed top end down into the water, the volume has to be replaced, but since the top end is down it sucks in the water. Also, at the end of the video, we have visual evidence that Harrison is habitually late.


This picture shows the units of pressure on the left and how we calculate air pressure at sea level.


This picture shows what we thought the graph of the function of pressure in terms of volume would look like


We performed an experiment which measured pressure through a syringe. Late Harrison pushed the syringe in and every 2 cm^3 we took a reading. This is a graph of that experiment, pressure as a function of volume. We did an inverse fit on it. p = A/V + B. This fit was better than just the standard inverse, p = A/V, since the B adds a little wiggle room which gives it a more accurate curve to match the graph.


This picture explains the experiment that we performed and also shows what the units of A would be.


Professor Mason heats the container to show the relationship between pressure and temperature.


My prediction of what the graph of the function of pressure in terms of temperature would look like. Sandy originally drew a straight line but I assumed it was curved so we went with that.


The actual function of pressure in terms of temperature. So our prediction would have been correct if I had left well enough alone, but that's not what Bob would do.


The beaker of air is placed in another beaker filled with hot water. This was one part of the experiment showing the relationship between volume and temperature.



Another part of the experiment involved placing the beaker of air into a beaker filled with ice water. 



The beaker of air was also placed in a room temperate beaker of water.


The above picture shows the graph of the relationship between temperature and volume.


The Boltzmann Constant is equal to the ideal-gas constant divided by Avogadro's Number. Rather than relating pressure and volume on a per mole basis, this constant relates these on a per molecule basis, and has units of Joules per molecule kelvin



The above two pictures show the diving bell problem. We first determine the pressure that the bell is under by equating it with the pressure of the water around it. Then we use the ideal gas law to determine the height at which the water raised.


Our assumption of what would happen with the balloon and marshmallows in the vacuum. Both would get larger as pressure goes down and both would return to normal size after.


The balloon before the air has been sucked out of the vacuum.



Most of the air has been removed from the the vacuum, and as a result the volume of the air inside of the balloon has greatly increased, causing the balloon to inflate.


The above picture shows the balloon after air is restored. It has returned to it's normal size.


The picture above shows the marshmallows before the air is sucked out, the one outside is our control group.


When the pressure drops the air inside of the mallows increases in volume causing the marshmallows to greatly expand.



In the picture above we were given the volume, pressure, molecular mass, and temperature of Helium in a balloon. With that information we were able to use the ideal gas law and find the mass of helium present.



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