Does water affect how fast something falls?

Answer 1

Yes, however, even air affects how fast something falls. The weight of the water is what causes buoyancy (certain materials to float), and and the resistance of water plays a small role - the weight of the water being the larger role - in what causes other materials to fall slower than they would through air. There are actually certain things that are buoyant in the air, like helium.

You will notice that if you let all the air out of your lungs, you will fall down through the water at a certain (very slow) speed. That speed is your terminal velocity through water. The terminal velocity of an average sized human through the air is about 55.6 m/s (200 kph or 124 mph). This speed is obviously much higher than the speed at which something falls through water. So water does affect haw fast something falls.

"But wait, certain objects appear to fall through the water at the same speed that they fall through the air!"

To explain this, water affects how fast something falls - compared to how fast it falls through the air - depending on its density. The object which you're talking about, is actually falling slower through the water, you just can't tell. We see this property in air too, why do you think a pound of feathers falls much slower than a lead weight?

Answer 2

No, the presence of water does not affect how fast an object falls in a vacuum or in air. However, water resistance can slow down the fall of objects due to friction and drag forces when the object falls through water.