4E30.10 Constant Volume Gas Thermometer


Ideal gas law, absolute zero


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



  • [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.


  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


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


  • Don't attempt this at home!

Last revised

  • 2018


Related AV

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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.