# 4E30.10 Constant Volume Gas Thermometer

## Concepts

Ideal gas law, absolute zero

## Overview

Measurements of pressure at different temperatures with a fixed volume can be graphed to demonstrate the ideal gas law and absolute zero.

## Details

### Equipment

• [1] Gas thermometer
• [1] Lab stand
• [1] 90-degree clamp
• [1] 3-finger clamp
• [2] 2000 mL beaker
• [2] Dewar
• [1] Mercury thermometer (-20 to 110 C)
• [1] Alcohol thermometer (-100 to 50 C)
• [1] Hot plate
• [1] Ice scoop
• [1] Bucket of water
• Water ice
• Dry ice
• Ethanol
• Liquid nitrogen

### Safety Equipment

• [1] Safety goggles
• [2] Safety glove

### Classroom Assembly

1. Put the ethanol in a dewar and pre-cool it with dry ice.
2. Put the liquid nitrogen in the other dewar.
3. Put water and ice in a beaker.
4. Put water in the other beaker. Heat the water on the hot plate, if desired.
5. Mount the gas thermometer on the lab stand using the 90-degree clamp and 3-finger clamp.

### Important Notes

• Be careful when putting anything into a dewar. The inside of the dewar is made of fragile glass.
• Liquid nitrogen, dry ice, and dry ice in ethanol can cause severe burns and blindness. Use with caution.
• Watch the hot plate to make sure the water doesn't boil out of control.

### Script

1. Put on your safety goggles and gloves.
2. Read the room temperature from a thermometer and the pressure in the gas thermometer.
3. Repeat step 2 with the gas thermometer immersed in the various media: liquid nitrogen, dry ice in ethanol, ice in water, and hot water.
4. Plot P vs. T and extrapolate it to absolute zero at P = 0.

## Additional Resources

#### References

• PIRA 4E30.10
• DHP Ha-4; Meiners 25-2.7; Disc 16-02

#### Disclaimer

• Don't attempt this at home!

• 2018

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If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.

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