Virtual Laboratory: Ideal Gas Law

First Physics 102 Lab
Due April 7

Overview

In this experimental module you will be working with several aspects of the ideal gas law. The simulated environment is that of a piston in a cylinder. This simulation has opened in a separate window from the text you are reading now.

You can control the temperature of the gas, the kind of gas in the cylinder, as well as the volume of the cylinder. A graph is part of this applet and that will record your data. Please note, that the 'detectors' used in this experiment have noise built into them so that you will not take perfect data. That means you have to make many measurements so that you have a statistically sound result.

The experimental procedure is fully outlined below. Please follow the instructions closely.

Technical Details

You should run this applet in Netscape 4.6 or higher and/or IE4.0 or higher.
Note that you can not print an applet. Thus when you see your graph build up, you can't just print that. If you know how to make a screen capture, you could capture the screen and print that if you like. This is not a requirement for this assignment. Just be aware that you can't print your results and therefore you will have to record them in another way, as specified in the instructions below.
This is a JAVA applet meaning that if you are doing this at home, once the code has been downloaded to your browser it will run even if you disconnect from the Internet.

Experimental Instructions

In this series of experiments, you will control the action of a piston in a pressure chamber which is filled with an ideal gas. The gas is defined by four states:

Temperature
Volume or density
Pressure
Molecular Weight

Warning: Be sure that the pressure in the chamber never exceeds 15 units!!!

If the pressure exceed this amount, the chamber will crack and the gas will leak out and your experiment will be over. Even though this is virtual gas, its effects could be unpredictable.

This experiment is setup so that changes in the state of the gas, e.g. its Temperature, Volume and Pressure, are automatically recorded on the graphical tool. This should guide the experimenter into understanding the relationships of the Ideal Gas Law.

First Experimental Procedure

click on the button titled constant volume - you will see that the default variable to plot are now pressure vs temperature. The initial values are Volume = 6, Pressure = 3.6 and Temperature = 273K. These values can be read on the respective meters/guages.
Now, for obscure reasons, you must prime the plotting tool.

Grab the thermometer with your pointing device and raise the temperature to around 400 degrees and release the pointing device.
Now lower the temperature back to around 300 degrees
Now raise the temperature back to 400 degrees. You should now see a graph with one or possible 2 points plotted. From now one the graph will respond to each new temperature position.

Change the temperature by moving the thermometer to a variety of different temperatures; each time you release the pointing device a new point should appear. Do this until about 50 data points are plotted but do not exceed a temperature of 800K.

Now answer the following questions and email your answers to the instructor: nuts@bigmoo.uoregon.edu.

Using this data, predict at what temperature the pressure will exceed 15 units. Send that prediction to the instructor (don't cheat).

Estimate the amount of noise that is in your detector. That is, at a given temperature, how accurate can the pressure be determined?

Second Experimental Procedure

Click on the button entitled constant temperature
Set the temperature to between 100 and 150K
Now go to the control panel under the piston where there is a button with a single arrow on it. This is the rightmost of the two buttons.
Each click of that button will depress the piston into the cylinder. Notice the pressure and volume meters change. Each click will plot 4 data points on the graph
Being careful not to crack the cylinder with excess pressure, plot out the relation between pressure and volume as the temperature is held constant. If you crack the cylinder hit the reset experiment button.
Is the relation between pressure and volume and constant temperature linear? That is, if you decrease the volume by a factor of 2 does the pressure increase by a factor of 2? If the relation is not linear, what form does it take. (hint: try looking at the product of pressure x volume at various settings).

Now close the experimental apparatus box and click on the following link the finish this assignment:

First Physics 102 Lab Due April 7