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Why do some objects go through water and air with no problem, and others have friction pushing against them in the water?


Both water and air are fluids. When things move through them, they experience drag, or a resistance from the fluid.


Creating smooth shapes make it easier for objects to move through fluids. The teardrop shape is the most efficient, which is why animals like whales and seals have that very sleek body shape. Airplanes also have a sleek shape in order to reduce drag as they fly through the air. 

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