How much less do we weigh underwater?

Question

Is it an equation? If it is, tell the equation please.

Answer 1

When you are under water, you don't way any less then you would on land but you feel "weightless", this is because the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body. This force enables the object to float or at least to seem lighter. The buoyancy of an object depends, therefore, only upon two factors: the object's submerged volume( how much fluid your body displaces), and the density of the surrounding fluid. The greater the object's volume and surrounding density of the fluid, the more buoyant force it experiences. If the buoyancy of an (unrestrained and unpowered) object exceeds its weight, it tends to rise. An object whose weight exceeds its buoyancy tends to sink.  So in salt water, where the water is more dense, you feel less weight and are more buoyent yet you still weigh the same. The reason for this is because buoyency is fighting againgst gravity( IE you float up in water when on land you would be forced down by gravity)

Answer 2

If you jump in the water and don't move, you'll float. Not like a cork, but you'll stay at the surface and not sink to the bottom. Therefore, in water you basically weigh less than nothing.

When scuba diving, to counteract the body's buoyancy, you generally wear a couple of lead weights. Depending on your body's size and density (fat content, etc.) you might need 5 pounds or so of lead to make your body "weightless" under water. In saltwater (which is denser than fresh water) you'll need a little more weight.

This is all because human bodies are a little less dense than water. If you remember from chemistry class in high school, water has a density of 1.0. People have densities of (I guess) around 0.98 or so, so we float. Lead has a density of about 11, so an 11-pound lead weight will weigh 10 pounds under water.

Answer 3

Maybe about ten pounds less.