how high can you jump and how long can you stay in the air?

But is jumping really flying? Yes and no. Some things like rockets, cannonballs, and baseballs fly like jumping kids_they are pushed into the air by engines or muscles. But what about airplanes? It's true they are pushed forward by engines, but air is what pushes and holds them up. Thrust, drag, weight, and lift are the four forces that usually work together to make things fly. You already know something about each of them, although you might not have called them by their names. If you thought that having stronger muscles or springy shoes or a rocket booster might help your jump, then you were thinking about thrust (the "muscle" that pushes you during flight). If you thought that a slick suit or helmet would make you jump higher or that a parachute would keep you in the air longer, then you were thinking about drag (the way air tends to slow things that fly). Obviously weight is important - if you could lose weight by changing clothes, dieting, or visiting the Moon, you would probably jump higher Most people have experienced how thrust, drag, and weight can help them jump higher or "fly," but few people are familiar withlift. Lift is a push that comes from the air. You were thinking about this force if you decided that wearing wings or holding helium balloons would help you jump higher. Planes and birds have to be moving to get enough of this push to fly; hot-air balloons are light enough for their size that the air will lift them up whether or not the balloon is moving. You may want to find out more about this key force to better understand how things fly. Does everything that flies use all four forces? Nope. Only two forces - weight and thrust - help spacecraft fly. Lift and drag won't help spacecraft flying in space, where no air exists. This was a quick overview of the forces of flight. Don't stop here, though - look for more information about how high you can fly. website:http://www.nasm.si.edu/exhibitions/gal109/lessons/text/look.htm