# If I’m in a pool, does my weight push down on the bottom if I’m floating?

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Is the bottom of the pool supporting the same amount of weight whether or not I’m standing on the bottom or floating on the surface?

Edit: thanks! Something something Archimedes

In: Physics

Well OP you could actually test this fairly easily at home. Grab a kitchen scale, a bowl, a small rock, something that floats that weighs as much as the rock. But the answer is yes your weight is added to the weight of the water pushing down.

When you get in the pool you displace some water. This causes the water level to rise slightly. Each square centimetre on the bottom of the pool now has a taller column of water above it. That taller column is heavier, and so applies a greater force on the bottom of the pool. So you getting in increases the pressure exerted on the bottom, and so the entire pool carries your weight.

If the pool was already full then some water would slosh over the sides, and that amount of water would weigh the same as you, so the total weight of water + person in the pool would stay the same.

Yes, you’ve added some mass to the pool, unless the water you displaced has drained out of the pool.

In order for you to be motionless in the pool, the total force on your body must be zero (thanks, Newton). When you’re in the pool, gravity doesn’t disappear. It’s still pulling you down. Which means something must be pushing back up.

You could (rightly) claim that the water is pushing you back up. But then there would be more force pushing down on the water. The water isn’t accelerating down, so something must be pushing it back up (it’s the bottom of the pool).

Yes.

The water level will rise by the amount of water that has the same weight as you. The bottom of your pool will receive that extra weight the same way as if you added more water.