Most cars burn gasoline for fuel. Gasoline is a fossil fuel made mostly of carbon. As it burns inside the engine, the liquid gasoline expands into a gas with a huge amount of energy that the car uses to move. The "How Things Work" site is one place to learn about: * how we use gasoline for energy and * how car engines work. The carbon gas combines with water molecules to form carbon dioxide as it leaves the engine. So what?? Carbon dioxide is a greenhouse gas that traps heat. As we put more and more heat-trapping gas into the atmosphere, our planet gets warmer... and warmer. Coming Next: What's my "carbon footprint"? And how much is too much? <--- hopeisgreen.com |  |