Hydrogen Generator

So i went to a showcase today and saw a hydrogen powered car and it got me thinking.  So i made a Hydrogen generator and here is how:
Parts list:
2 10 CM bits of copper wire
2  D Batteries
A cup
Step 1 : Strip the copper wire on both ends
Step 2 : Put one end of each wire in the cup with some water( make sure that the copper part of the wire is in the water)
Step 3 :Take the batteries and put them together
Step 4 :Touch the other ends of the wire to the batteries and then you should see small bubbles coming from one of the wires
It should look kinda like this

By: Trevor Eady