When you jump into a pool where is your weight “carried”? Does it increase the pressure on the bottom of the pool?



When you jump into a pool where is your weight “carried”? Does it increase the pressure on the bottom of the pool?

In: Physics

Yes! The pressure throughout all points in the pool increases because the height of the water above it increases as you displace the water that was once where your body is. The water is carrying you because there is enough push upward to hold you there, since you are not dense enough to provide enough downward push to overcome it. The pool is also holding you, as it has to hold all the water, and you at the same time.

Pressure causes force in all direction, and the force increases with depth, as I’m sure you know. The water below you is pushing up, because the water around it is pushing in, forcing the water to go up as there is no other place to go. How much water you displace will determine how strongly the water around you pushes you up, and your weight determines how much force you are pushing down with. When something floats, it doesn’t have to float on the surface, even dense objects can rest within the water, without laying on the bottom, if it is able to find a depth where its weight and the upward, or bouyant, force of the water is equal. Knowing this, the water below you is holding you, and technically the entire body of water is what is truly holding you. More weight on top means more pressure on the bottom!

It’s carried by the buoyancy of the water. Let’s imagine you jumped in feet first and are completely underwater. Water exerts pressure in all directions based on the weight of the stuff above it. They water at your feet has more stuff above it than the water at your head, so there’s an upward force at your feet and a smaller downward force at your head which creates a force pushing you up. If you were a bowling ball the upward force would be smaller than your weight and you would sink to the bottom.

You held your breath though, so the upward force exceeds your weight and you are pushed upwards. After you break the surface the only downward force is from the atmosphere and once the force of your weight is equal to the upward force of the water you stop rising and float. This happens when the volume of you underwater is the same volume that your weight in water would take up. If you weigh 135 pounds, you will displace 135 pounds of water. You are bigger than 135 pounds of water, so some of you will be sticking out.

Technically, pressure goes up over the whole pool because you being in the water makes the water level go up meaning the water is deeper everywhere else. An Olympic swimming pool has 5.5 million pounds of water, so our 135 lb person makes the bottom feel 1.000024 times the pressure without you in the pool.

Yes – you displace some water, which means the water level increases, that increased depth means a higher pressure, and therefore force, on the bottom and sides of the pool