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Waffle's Crazy Peanut
Waffle's Crazy Peanut
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If I put a couple of lead bricks on my foot, there would be a definite sensation of a heavy, perhaps even painful, force. Calculating the pressure for 20kg$20 kg$ of lead over a 100cm2$100 cm^2$ area of my foot, I get about 20kPa$20 kPa$.

Now I stand underwater in a pool. If my foot is 2 m$2 m$ below the surface, then the hydrostatic pressure would be density x the depth x gravity$\text{density} \times \text{depth} \times \text{gravity}$, or 20kPa$20 kPa$. Same as above. But in this case I wouldn't feel any pain or high pressure on my foot. Why the difference in sensation when under water, even though the pressure is the same in both cases?

If I put a couple of lead bricks on my foot, there would be a definite sensation of a heavy, perhaps even painful, force. Calculating the pressure for 20kg of lead over a 100cm2 area of my foot, I get about 20kPa.

Now I stand underwater in a pool. If my foot is 2 m below the surface, then the hydrostatic pressure would be density x the depth x gravity, or 20kPa. Same as above. But in this case I wouldn't feel any pain or high pressure on my foot. Why the difference in sensation when under water, even though the pressure is the same in both cases?

If I put a couple of lead bricks on my foot, there would be a definite sensation of a heavy, perhaps even painful, force. Calculating the pressure for $20 kg$ of lead over a $100 cm^2$ area of my foot, I get about $20 kPa$.

Now I stand underwater in a pool. If my foot is $2 m$ below the surface, then the hydrostatic pressure would be $\text{density} \times \text{depth} \times \text{gravity}$, or $20 kPa$. Same as above. But in this case I wouldn't feel any pain or high pressure on my foot. Why the difference in sensation when under water, even though the pressure is the same in both cases?

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BrianC
BrianC
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Why don't I feel pressure on my body when swimming under water?

If I put a couple of lead bricks on my foot, there would be a definite sensation of a heavy, perhaps even painful, force. Calculating the pressure for 20kg of lead over a 100cm2 area of my foot, I get about 20kPa.

Now I stand underwater in a pool. If my foot is 2 m below the surface, then the hydrostatic pressure would be density x the depth x gravity, or 20kPa. Same as above. But in this case I wouldn't feel any pain or high pressure on my foot. Why the difference in sensation when under water, even though the pressure is the same in both cases?