Big Bang [Music] whoa look did they just jump out of that play I want to try that they're gonna fall way too fast oh I get it now they're using a parachute to increase their air resistance air resistance what's that I want you to move this plastic bag left and right try it out so Amy how is it I can feel some kind of force dragging this bag that's the theory of drag [Music] is the force that acts opposite to a relative motion of an object to make it slow down hmm this sounds like friction but doesn't friction require two surfaces to touch drag is a type of friction between an object an air or water for air we usually call this air resistance when you run you can feel the air hitting on your face that is air resistance in action here's the fun fact chipsters planes and race cars have a special design to reduce air resistance so it can travel at a faster speed we call it a streamlined design oh is that why fast vehicles are sharper in the front 10 out of 10 Amy you're a natural well you see Amy air resistance doesn't only work when we're moving horizontally it also works when removing vertically meaning that it can act in the opposite direction of gravity wait if gravity pulls us down does air resistance pull us up well Amy air resistance would never be big enough for us to go up but it can slow us down hmm but last time we learned that if two objects have different Mass they will still touch the ground at the same time you're right Amy but that only applies when there is no air resistance take these two same pieces of paper and crumple one of them into a paper ball then drop them from the same height at the same time three two one [Music] the paper ball landed on the ground first it's all because of air resistance when we drop a piece of paper it can catch more air causing it to fall slower the paper ball can't really Catch Air so it fell faster than the piece of paper now let's imagine that we do the same thing but on the moon which one will hit the ground first chipsters three two one wow they both landed at the same time but why oh because there is no air on the moon there is no air resistance to slow the piece of paper down there are two factors that can affect an object's air resistance the traveling speed of the object and its surface area the faster an object travels the more air resistance it experiences that's why the faster we run the more wind we can feel the surface area of the object is the area of the outermost layer of an object the larger the object the more air resistance it experiences for example this blue plane has a larger surface area than that red plane when the force of motion is equal to the air resistance the object will move at a constant speed meaning it won't go any faster first question Which experiences more air resistance a bicycle or a truck ding ding ding because a truck is bigger and has a larger surface area than a bicycle the truck would experience more air resistance very good chipsters it's your turn to try it now join my experiment to see how to make your own parachute want to watch the full video sign up now and get started with your own free trial