Lighter Than Air

Although the force of gravity applies to most everything on Earth, some objects, such as this balloon, are able to remain above the ground. This balloon can float because it is filled with helium, which is a gas lighter than those which comprise our atmosphere. This should not be taken to mean that the balloon is actually defying gravity. The balloon is still being pulled towards Earth, but because it is filled with a lighter gas than others in the atmosphere, a relatively stronger force is exerted on the heavier gases, allowing the balloon to float above them.