Water Break

Here's a way that you can break the compound water into its elements - hydrogen and oxygen - using electricity.

What you'll need:
2 6-8" pieces of insulated copper hookup wire
4 alligator clips
Wire strippers
Water
Small glass or jar (not made of metal!)
Two pencil "leads" (for mechanical pencils, they're really made of carbon)
Tape
9-V battery

First you'll need to put together the wires; you'll probably need an adult to help with this step. Cut the wire to the length indicated, then strip about 1/2" of insulation from each end. Connect an alligator clip to each end.

Put about 2" of water into the glass or jar. Stand the pencil leads up into the water about 1" apart. The tops should extend above the rim of the glass. Tape the leads to the sides of the jar. Clip one end of each wire to the top of each lead. They break easily, so be careful. Connect the other ends to the battery terminals. There is now be a path for the electricity to flow from one battery terminal, down the wire to the lead, through the water to the other lead, up the other wire, and back through the battery.

Watch the leads carefully. After a few minutes, you should see bubbles forming. They are not filled with air. The bubbles around one lead are hydrogen gas; the bubbles around the other are oxygen. You have successfully split the compound water into its two elements!

When you're done, just unhook the wires from the battery and take everything apart. Throw the water away and wash the glass.