Air is all around you, but since it’s invisible, it might be easy to forget that it’s always there. Airplanes rely on air to be able to fly. Many forces work together to keep the plane in the air, and one of them is called lift. Because of the shape of airplane wings, air moves faster on top of the wing and slower underneath the wing. Faster moving air, like the air above the wing, has lower air pressure. Slower moving air, like the air below the wing, has higher air pressure. Air pressure is a way of measuring how much the air is pressing or “pushing” against everything it touches. Imagine that each air molecule has tiny hands that are pressing on the wings of the plane. Since the air above the wings of the plane has lower air pressure, there are fewer air molecules pressing on the wings of the plane. The air below the wings has higher air pressure, meaning there are more molecules “pushing” up on the wings of the plane. This force, called lift, created by the shape of the wings and the differences in air pressure, keep the plane in the air.