Sea water has a higher density than fresh water. Would you be able to float in sea water than in fresh water.?

Question

Explain the physical reason.

Answer 1

Yes, you float higher in sea water than in fresh water.

Metal warships float because the volume of sea water they displace is denser then they are. So the sea actually provides a force that pushes up against the hull. In fresh water that density drops so to would the draft (depth in the water) of a metal ship.

The Dead Sea is the saltiest sea in the world and it is easier to float there than in any other sea because the water is so much denser. Because of the extra salt it is easier to float in salt water than in fresh water.

Humans float easily in water because we are over 90% water ourselves. We also have body cavities that make us less dense, just like those heavy ships do. If that ship was solid steel then it would sink just as you would if you were solid matter. When a tanker is full of oil it rides lower in the water, but there is empty space around the tanks to decrease the ship’s density so it will float. When that hull is punctured then the water can flood in and the ship can sink.

The human body has only a few cavities in it so you need to concentrate on floating. The way a human floats is determined by the position of their lungs; where the body density is the least. This is why you can do a dead man’s float on your front or a back float and in both situations your legs hang down to the bottom while your chest is high in the water. If a human drowns, then they lose that space in their lungs; it gets filled with water and they sink. When the body has a chance to decompose there are trapped gases in it which bring it back to the surface.

Look at this table: http://www.simetric.co.uk/si_liquids.htm and http://www.simetric.co.uk/si_water.htm
- sea water has a density of 1021.98 to 1025.18 kg/cubic meters at 25 degrees C (77 degrees F).
- fresh water has a density of 0.9982 kg/cubic meters at 20 degrees C (77 degrees F).
If you look at the second table (http://www.simetric.co.uk/si_water.htm) then you will see that as the temperature decreases the density increases. This makes sense because the molecules are moving less at colder temperatures so they need less volume, but the weight is constant therefore they increase in density.

According to the first Chart: http://www.simetric.co.uk/si_liquids.htm
Oil’s density varies from 790-973 kg/cubic meter at 15.56 degrees C (60 degrees F) so you can see why it floats on water, it is less dense. If you look at the chart further you will see that there are a lot of liquids that aren’t as dense as water. Water is very dense and very heavy. One big problem with a Lunar or Mars Colony is the required water is so heavy that NASA is looking for a source on the Moon or on Mars.

Answer 2

It would be easier to float in seawater because human density is less than that of salt water. In fact, in the Dead Sea in the middle east, salt content is 7x higher than everywhere else around the world making it nearly impossible to drown. The human body simply floats on top.

Answer 3

You float if the weight of water displaced by your body volume exceeds your body weight.

Your body volume = V
Weight of water displaced = ρgV
If ρ is higher, then that means you are better able to float.

What it actually means is that a smaller fraction of your body will be submerged underwater.

Answer 4

Check out "salt and Sea" on Google
The place is in California and it has so much salt content, that practically everything floats.

It is also man made, so that might explain why it is like it is, or maybe not.

Answer 5

yes. you naturally would have an easier time since most humans are less dense than salt water. Fresh water doesnt have as many molecules to hold you up