Water Wall

This experiments is one of those that comes from two different projects coming together. I got an e-mail this week from an educator asking for experiments that could be done with spoons. While I was digging through experiments spoon experiments, I got a request to help design some exhibits on the science of water for a new museum. The two projects came together into a fun, easy way to make a solid, thin sheet of water.

To do this, you will need:

  • a spoon
  • a faucet

This one is a very easy experiment to do. Turn on the faucet to a stream about as thick as your finger. Now hold the spoon so that the stream of water hits in the bowl of the spoon. You would expect that the water would splash in all directions, but something very different happens. Instead of a spray, the water forms a thin sheet of water, spreading out from the spoon. Why does this happen?

To understand that, we need to take a close look at a molecule of water. The chemical formula for water is H2O. That means that a molecule of water is made up of two atoms of hydrogen (H) and one atom of oxygen (O). The hydrogens are stuck to one end of the oxygen. Imagine the oxygen atom as Mickey Mouse's head and the two hydrogen atoms are the ears. This arrangement causes the water molecule to be polarized. One end has a positive charge and the other end has a negative charge. Since opposite charges tend to stick to each other, the molecules in a drop of water act like a pile of magnets. They all stick together.

When the stream of water hits the spoon, it spreads outwards. Instead of breaking up into lots of droplets, the water sticks together, forming a thin sheet. As it spreads outwards from the spoon, it spreads into a thinner and thinner sheet, until finally it breaks up at the edge. As you turn up the stream of water, you can get the sheet of water to extend out quite a long way. Try some of the other silverware, comparing forks, knives, etc. You can even try glasses, plates, etc. In fact, add a little soap and before you know it, you will have washed all the dishes!