2B40.20 Archimedes' Principle


Buoyancy, Archimedes' principle


This experiment compares the buoyant force on an immersed cylinder and the weight of water displaced by the cylinder.



  • [1] Steel cylinder
  • [1] Steel cup
  • [1] Glass beaker with downward spout
  • [1] Glass beaker
  • [1] Spring scale
  • [1] Bottle of water
  • [1] Lab jack

Classroom Assembly

  1. Put the large-spouted beaker on the lab jack and position the other beaker to catch the runoff from the spout. Adjust the lab jack as necessary.
  2. Fill the large-spouted beaker with water.

Important Notes

  • Keep electronics away from the water!


  1. Use the spring scale to measure the mass of the cylinder.
  2. Lower the cylinder into the large-spouted beaker until the cylinder is immersed. Make sure the other beaker catches the runoff.
  3. Read off the apparent mass of the immersed cylinder. The difference in mass can be used to calculate the buoyant force.
  4. Carefully pull the cylinder out of the water.
  5. Show that the cylinder fits snugly in the cup.
  6. Measure the mass of the empty cup.
  7. Add the runoff water to the cup. Show that the cup is full.
  8. Measure the mass of the water and the cup. The weight of the water should equal the buoyant force.


Additional Resources


  • PIRA 2B40.20


  • Don't attempt this at home!

Last revised

  • 2020


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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.