why does the human body float when placed in water?
412606
I'm not sure, all the answers make sense, I thought maybe the fluids and gases in our bodies kept us afloat for a while then once dead the fluids and gases escape and the body sinks until it bloats and then rises again
770625
I'm sorry, i have to correct some of the misunderstandings posted above here.\n\nTHE WEIGHT DOES NOT, I REPEAT, DOES NOT CHANGE IN WATER.   weight is a term in physics for the interaction of gravitational forces on a masseous object.  Does the mass of the object change in water?  NO.  Does the mass of the earth change when an object enters water?  NO.  Therefore the weight is the same.\n\nWhy do objects feel lighter in water?  the difference in net force is the answer.  Weight still pulls down equally... However, the water creates a boyent force which counteracts a percentage of the weight (depending on the object submerged.  roughly counteracts 40% for humans, different for other objects).  In this way, while the weight is the same, the downward force of the object is less.  That's the confusion point for almost everyone who's answered so far.
164167
First off most people don’t sink when they are alive.  Only very thin people or very muscular people will sink when they are alive, and even then they need to breath out to do it. Most people have more than enough fat on their bodies to keep them lighter than water, and they float. \n\nSome people sink when they drown for the same reason that thin or muscular people sink when they breathe out the air in the lungs acts like an inflatable swim toy and bouys people up. When people drone they breathe water  into their lungs. With along full of water the body becomes more dense and in many cases dense enough to sink. Note however that even moderately fat people won’t sink even when they drown. Fat and oil are much less dense than water and keep them bobbing to the surface.\n\nSome bodies will initially sink when they die and will then rise to the surface again. That’s because the body starts to rot. When it rots the bacteria produce gases like methane and carbon dioxide. These fill up the skin like a balloon. Since the body is now full of gas it bobs to the surface like beach ball.
159084
Ice floating is because of water's expansion upon freezing. It lowers the density below that of liquid water, meaning it floats.
152879
No, it will not.  The other answers to this question are on the right track, in that they point out that an object's density is the key thing in most situations, since if it is less dense than the fluid it is in, it will displace fluid equal to its weight before it is completely submerged, and hence float.\n\nBut in *this* problem, we are told from the outset that there is not enough water to be displaced.  Therefore, the object will displace all the water, all 1 lb. of it, and still not have displaced enough water to equal its weight.  Therefore, it will rest on the bottom, i.e. not float.
943048
Whenever the mass of an object is less than the mass of the liquid it displaces, it will float.  That's why a hunk of steel won't float, but a ship made of steel, enclosing lots of unoccupied space, will float.\n\nAs for the ice cream, its made up of lots of fat molecules whipped into a semi-solid.  Its mass is less than the mass of the root beer it displaces...therefore it floats
460243
i assume you mean why dont the rotten eggs "drown" as in sink. well this is because when they go rotten as the egg starts to decay it broduces gas, mostly methane and sulphor so this means thats the egg becomes lighter so making it float.
149451
Objects float because the density of the object is less than the density of the liquid. If you increase the density of water by dissolving something, such as sugar or salt, in it and create a situation where the density of the water exceeds the density of the egg, the egg will float.
236062
Because of its shape. \n\nA ship, when placed in water, forces some volume of the water to move (displace) and make place for the ship. If the weight of the displaced water is more than that of the ship, the ship will float. \n\nIn other terms, the average density of the ship is less than that of water and hence it floats on water.
656787
A newly dead human being, or any other animal, will sink when placed in water.  After the gases of decomposition build up in the chest and abdomen, however, the body will inflate, rise like a hydrogen-filled balloon, and pop to the surface, sometimes dragging with it surprisingly heavy weights that a murderer might have thought sufficient to keep it down.   With the passage of time and further decomposition, however, the body cavities eventually rupture, the gas escapes, and the corpse goes down again, this time for good.\n\nThere is one notable exception:  sometimes, due to air caught in the clothing, a body will stay on the surface for several hours before sinking.
888797
We weight the same, regardless of whether we're in water or not.  Buoyancy and density give us the feeling of weighing less in water.  You would get the same answer if you filled that tub with 150 lbs. of rocks.  Rock just happens to be a lot more dense than water, and not as buoyant as the human body :)\n\nVolckhart\nhttp://www.zeuslegacy.com/register.php?ref=2854
110828
Archimedes said: When an object is submerged in water, there is a buoyant force upwards on it that is equivalent to the weight of the water displaced. \n\nSo if you have a heavy object underwater, and it is displacing water, its net weight will be less than when it is in air, displacing air, which is much lighter, so has a much smaller buoyant effect.
1184219
an extra floatation device for added safety
101072
we have a epidermis layer on our body. in the hand the layer is thin.\nwe also have sweat glands all over the body.\nwhen we are in water for long time there is diffusion of the water from the fingers to the water source. \nso there is wrinkeling taking place
689832
The object must be less dense than the fluid to float, and more dense to sink.  If it is exactly equal density, then it can be suspended.
196335
A ship can float on water because the desity of the ship is less than that of the water arround it.  When I speak of the Density, I speak of the ship as a whole.  The materials can be much more dense than water including steel or even Concrete.  What matters is what is in the ship.  If there is mostly air or something light in the ship, the average desity of the ship is very low and the ship will float high in the water.  If there is a lot of heavy cargo, the ship will float low in the water, unless too much cargo is loaded that is too heavy, then the ship could actually sink.\nWhen the ship is sitting on the water, it is displacing a certain amount of water.  The surrounding water then places pressure upon the ship pushing inward and upward.  The ship, not weighing as much as the water that is displaced is held up by this pressure.  If the wieght of the ship becomes more than what is displaced, then the ship will sink.
1026719
Buoyancy\n\nThe buoyancy force is a force exerted by a fluid on an immersed object and is equivalent to the weight of the volume of such fluid displaced by that object. Water serves as a particular fluid in this case.  The water buoyancy provides large mammals such as such as whales an environment were they can survive our planet’s gravitational pull. As we know, beached whales get suffocated as their lungs compress under the weight of their own body. \nOceans waters also provide abundance of food to support their huge frames, but this is another story :) .