How many drops of water can be placed onto the surface of a 5 cent coin before it spills over the edge of the coin?

The power of surface tension can be used to help you break the record! This little but amazing challenge can teach your budding scientist about surface tension, and more. Enjoy the challenge and …good luck.

  • 5-cent-water-challenge-materialsPipette
  • Water source
  • 5 cent pieces
  • Several scientists wanting a mini-challenge



1. Water can be a split hazard. Clean up and water spilt immediately.

  • 5-cent-water-challenge-step1Place very carefully, drops of water on the surface of the coin.
  • Keep adding (and counting) before the water spills over the edge.
  • 5-cent-water-challenge-finishThe person who gets the most drops of water on the coin before it spills over the edge is the winner!

Check out the ‘Wacky Science’ video of this experiment and ‘What’s Going On’ series link. They are currently ‘In Production’, so check back soon…..

Wacky Science Ep

What's Going On?



This little gem of an experiment can occur due to a chemical force called ‘surface tension’. Between water molecules there is an attractive force called H-bonding which causes the water to form a ‘skin’ on the surface.

It is this skin that allows water insects to walk on water and even a lizard called the Jesus lizard.

The surface tension holds the water drop and contains the volume of water until a point where the water drops size to so large that it breaks the surface tension.


5c water surface tension



If you would like

– more details,

– pictures of the second half of the experiment

– information on how to investigate this further

– links to everyday examples

– management hints & teaching pointers (5P Teacher develpoment program)

 ….. then why not subscribe to one of the following


(1) Crazy science Club

Crazy Science Club slider5

(2) 5P Teacher Training course called ‘Looney Lab  Classroom Creations

Looney Lab Classroom Creations2


Or you can purchase the ‘Bright Sparkes Guide’ of this demonstration only ($2.50) which has:

    • HD pictures of experiment steps
    • Detailed explanation of science
    • Mini-challenge section (another experiment)
    • Making it a ‘Scientific Method’ experience
    • Graphing opportunities
    • REAL links and descriptions to everyday examples of concept.