principle behind the floatation of an iceberg?

Question

I really need to know about the floatation of an iceberg (the principle behind it) in detail for a school project. Can anyone help or suggest some helpful sites? Thanks...

Answer 1

When the weight of the water displaced by the ice equals the weight of the iceberg, the ice stops sinking. That's called buoyancy. The sinking stops (and the floating begins) when more than 2/3 of the iceberg is below the surface (which is one thing that makes them so dangerous to ships). Thus, the vast majority of the bulk and the area covered are under water where ship's crew cannot see them.

Icebergs are formed when glaciers break off at the water's edge. Glaciers are formed by crystalized mositure from the atmosphere or snow (although the Antarctica is a desert so it rarely snows there). They are frozen fresh water.

Contrary to what one answerer answered, salt water does freeze and it does trap the salt ions (Na+ and Cl-) in the ice. But because of the salt ions, salt water, like the ocean, freezes at a slightly lower temperature than fresh water. Salt water freezes at -1.8 deg C rather than 0 deg C for fresh.

Frozen sea water (like in the Antarctica) creates what are known as fast ice, land fast ice, or shelves. The Ross Shelf is one of the largest on Earth. These ice shelves are created when the air temperature is so low that the water surface under it drops below -1.8 deg C.

When the shelves break up, like during their summer, they form what is known as floes...chunks of ice shelf carried away by tides and currents. These floes are also dangerous to shipping, but not so much as the icebergs. They are less dangerous because they tend to be smaller than bergs and because the area you see on the surface is is also the area underneath the surface; so they can be readily avoided.[See source.]

Answer 2

On earth, water is generally in liquid form. When the temperature gets cold, it freezes and forms ice, a solid. Because of the property and shape of the water molecules, when it freezes, it forms a lattice. See picture here - http://www.nyu.edu/pages/mathmol/textbook/hbond_ice.gif

The ice lattice is less dense than liquid water because there's a lot more empty space in between the molecules, making it a lighter substance and it floats to the top.

In the ocean, the water is also salty... so the density is even higher than pure water (ie, it's even heavier than normal water) so everything (including ice) floats better.

The principle of solids floating in fluids is called buoyancy - as long as the weight of the "displaced" water is greater than the object, the object will float. To learn more about buoyancy including pictures (yey) and equations (eek)-
http://hyperphysics.phy-astr.gsu.edu/hbase/pbuoy.html

To learn more about the property of water molecules -
http://en.wikipedia.org/wiki/Water_(molecule)
http://www.lsbu.ac.uk/water/molecule.html
http://www.nyu.edu/pages/mathmol/textbook/info_water.html

P.S. I'm making this answer basic because I know sometimes young children read these things. I don't mean to make it too redundant for you. Keeping in mind your reqest, I put in lots of external resources.

Answer 3

Good answers, just what I was looking for.

Answer 4

actually this is bcoz of buonyancy provided by water which is equal to vdg where g=gravity,v=volume of object submerged inside water,d=density of water,now body will float when its own weight is equal to buonyancy or vdg
therefore,
vdg=mg
vd=m
since mass=V*D(where D=density of object,and V is complete Volume of object)
vd=VD
d/D=(V/v)
since (V/v) can be equal to 1 or greater than 1
therefore d>D or d=D
hence for floatation density of object should less or equal to density of water,same principle is also behind floatation of iceberg on water.

Answer 5

Ice is a solid and therefore the rules of displacement apply as with any floating object. IE ships can be made of any solid and will float as long as the displacement ratio is sufficient.

Answer 6

An iceberg is frozen water. Frozen water is ice. Ice is less dense than water [water having a density of one] and anything less dense than the surrounding area it's submerged in..floats. google it.

"Water is one of the few substances that is actually less dense in solid form than in the liquid state."


http://www.geocities.com/yosemite/rapids/4233/floating.htm

Answer 7

The "basic principle," or what most would call the "mechanism," behind evolution is heritable variation acted upon by natural selection.

Answer 8

well there's this wierd propery of water anonymous expansion well after 4 degrees celcius it starts expanding and not contracting like other solids so volume increases and mass remains same
therefore
density = mass/volume
therefore density is less greater buoyant force on lesser mass and thus ice floats and salt water has greater upthrust and so it floats even more.

Answer 9

The "principle" is nothing but buoyancy. Ice is slightly less dense than water, so it floats. It is nothing more than that.

Answer 10

Ice is less dess than water.

So it floats.

Ice is even less dense than salt water.

So it floats more (the salt gets left behind when ice freezes).