On the right side of the main screen is a very
schematic experimental apparatus. Pressure is established by a movable loaded piston and
measured with a mercury manometer. The number and size of weights on the piston are
consistent with the pressure. This SIR simulates the behavior of an ideal gas. You may conduct experiments on the screen in which you set the amount of a gas or a mixture, choose the temperature and pressure, and watch the volume of gas respond accordingly.
On the right side of the main screen is a very
schematic experimental apparatus. Pressure is established by a movable loaded piston and
measured with a mercury manometer. The number and size of weights on the piston are
consistent with the pressure.
Temperature is established by a thermostat with a heat exchanger, and is measured on a thermometer. Volume can be read from a scale on the cylinder within which the piston slides.
The temperature, pressure and amount (in grams) of gas are controlled using the mouse on the menu on the left of the screen. You change the amount of a gas by clicking on its box and entering the mass, in grams. Given decent screen resolution you should be able to read each scale to better than 1 percent of full scale (1000 torr, 35 litre, and 350K spans).
You may, if you wish, simply use this as simulated experiment, read values directly from the screen, and use them to discover Avogadro's, Boyle's and Charles' laws. However, it is best to do at least one demonstration "live", and then use this SIR to simulate others that would be too time-consuming.
This SIR provides a notebook to record data, and suitable graphing facilities. You may plot volume vs. pressure or 1/P for Boyle's law, and volume vs. temperature for Charles' law. The temperature graph may be extended to below -280° , and you may add a Kelvin scale to it.
You may discover Avogadro's law quite dramatically. If you put into the notebook points for various masses of the (up to) five gases at constant temperature and pressure, the plot will show the five gases with different colours and symbols. You may then lay straight lines on the five gas plots, and discover that the masses are proportional to molecular weights.at any given volume.
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Updated July 25, 2000