## Due 3:30 pm, Thursday, November 19th

Physics 105, Fall Term, 2009

Did you complete the reading assignment?

Yes
No

## KEY CONCEPTS:

1) The ideal gas law relates the pressure, volume, number of molecules, and temperature of an ideal gas together.

2) The ideal gas law is an approximation that only works for ideal gasses.

The ideal gas law is a combination of Charles's Law, which relates volumes of gasses to temperatures, and  Boyle's Law, which relates the pressure and volume of gasses. To see how these relationships occur, go to: http://phet.colorado.edu/sims/ideal-gas/gas-properties_en.jnlp. Notice the pressure gauge and thermometer on the applet which give you numerical values for the pressure and temperature of the inside of the container. The number of molecules can also be measured quantitatively because there is a counter for the number of particles on the right side of the applet. Measurements for volume will need to be done qualitatively.

Put several molecules of gas into the box by pumping the pump a few times. When the number of molecules is increased, what happens to the pressure?

Pressure increases
Pressure decreases
Pressure stays the same

When the number of molecules increases what happens to the volume?

Volume increases
Volume decreases
Volume stays the same

When the number of molecules increases, what happens to the temperature?

Temperature increases
Temperature decreases
Temperature stays the same

Now increase the volume by clicking on the handle on the left side of the box and dragging it to the left. When the volume of the gas increases, what happens to the number of molecules?

Number of molecules increases
Number of molecules decreases
Number of molecules stays the same

When the volume of the gas increases, what happens to the pressure?

Pressure increases
Pressure decreases
Pressure stays the same

When the volume of the gas increases, what happens to the temperature?

Temperature increases
Temperature decreases
Temperature stays the same

Now increase the temperature in the box by dragging the scroll bar labeled heat control up and leaving it there for a short time. When the temperature of the gas increases, what happens to the number of molecules?

Number of molecules increases
Number of molecules decreases
Number of molecules stays the same

When the temperature of the gas increases, what happens to the pressure?

Pressure increases
Pressure decreases
Pressure stays the same

When the temperature of the gas increases, what happens to the volume?

Volume increases
Volume decreases
Volume stays the same

How would your findings be different if you performed all of the tasks above in a balloon instead of a rigid box?

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Was there anything that you didn't understand in the reading assignment?  What was confusing to you?