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To the scientist: What I do not understand about water physics, is that with fifty pounds of gear on your body and approximately three atmospheres of pressure on you, you can still float in that area. Why?

What is important for floating is the RATIO of your weight to your volume. If that ratio is greater than the local density of water, you sink. If it is less, you rise to the top. If you can match the water density, then you can float in place. So, there is no problem carrying an extra 50 pounds of gear on you as long as that gear occupies about as much space as 50 pounds of water would. You have probably noticed fat people do not have any trouble floating - fat is lighter than water, and so even though they may weigh a lot more, the extra volume more than makes up for it.

Arthur Smith

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