flight
g's school had a science fair. i don't expect much from 3rd and 4th graders. but it still saddens me that folks don't know how an airplane wing produces lift. two kids presented this topic. one got things more wrong than the other. newton's third law: for every action there is an equal and opposite reaction. the reaction is the wing being pushed up. but what's the action? this is the question the kids couldn't answer. it's the air being pushed down. so the next question is how does the wing do it? the answer can be demonstrated at a sink. turn on the faucet so you have a nice laminar flow. touch it with your finger tip. the water follows your finger and is deflected towards your hand. the action. the equal and opposite reaction is your finger being pulled towards the water. same thing happens with air across a wing. the air sticks to the surface of the wing and is deflected down. the reaction pushes the wing up. simple, no?