 Can you guess what kind of gas was in the balloon you just saw explode? If you guessed hydrogen, you're right. Hydrogen is an element that's usually found in its gas form. Although hydrogen makes for great explosion, it's also really useful. For example, today we're going to talk about hydrogen fuel cells. Hydrogen fuel cells are a lot like batteries. They use chemical reactions to produce electricity. Many hydrogen fuel cells use pure hydrogen as their fuel. There are many ways to obtain pure hydrogen, but today we're going to electrolyse water. Electrolyzing water means to apply an electric current to water molecules to decompose them into hydrogen and oxygen. Here we have two electrodes in water. We're applying a current with the help of a battery. The bubbles forming on one of the electrodes are made of hydrogen gas and the ones forming on the other electrodes are made of oxygen gas. The same thing will happen here in this model fuel cell vehicle. So the battery will provide the current to electrolyse the water. The motor of the car uses the electric current produced by the fuel cell. Fuel cell technology in vehicles may one day provide an alternative to the gasoline internal combustion engine. It has the potential to greatly diminish emissions. The world's first demonstration vehicle using only fuel cell technology was created by Ballard Power Systems, a Canadian company. You can check out the Ballard fuel cell here at the Canada Science and Technology Museum.