Experiment: Coriolis

The world is turning around and around… all the time! And this has a big influence on where ocean currents go and how winds blow (It doesn’t, however, influence the vortex that appears when you drain your bath tub!). We call this the “Coriolis effect” or “Coriolis force”.

For the experiment, you’ll need:

  • a cutting board
  • a long ruler
  • glue or tape (to glue the ruler to the cutting board)
  • a pencil
  • a couple of pens
  • a white paper
  • a second pair of hands (someone to help you with the experiment)

Cut out a large* circle from he paper and pin it to the middle of the cutting board with the pencil (check with your parents first that they are ok with that!). Glue or tape the ruler onto the cutting board such that it goes over the paper circle.

Now draw a line along the ruler’s edge while your helper turns the paper circle clockwise. What do you see?

The paper circle represents the world as seen from the South Pole. What would the same thing look like from the North Pole? Turn the paper circle the outer way round to find out!

*but the diameter needs to be smaller than the length of the ruler!