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.

Deftying Gravity

If gravity pulls all objects within range towards Earth, how do some objects, like planes, defy gravity? So, the specific example of an airplane actually requires a long explanation for its ability to fly. This explanation involves the concept of the airplane's wings generating a lift by making use of Newton's laws, along with several other concepts. What is important to understand, however, is that because a plane has its own acceleration and power, in addition to an aerodynamic shape and other aspects, it is able to push against the force of gravity (which is still acting upon it), take off into the air, and remain airborne for an extended period of time.



Aerial view of California