why does ice float on water ?

Answer 1

Ice is less dense than water

Answer 2

Ice floats because the weight of the water that the ice displaces is greater
than the weight of the ice itself. This is the principle of buoyancy. The
difference in the two weights is the buoyant force acting on the ice.

The same volume of water can have two different weights, if one is liquid and
the other is solid [ice] because the density [weight per unit volume] of liquid
water is greater than the density of ice. Water is one of the very few
materials that exhibit this behavior.

Earth is fortunate that water ice does expand and float. Just imagine what
would happen if ice sank instead! All the water in the world would freeze and
sink to the bottom of the oceans; the next bit of water would freeze and sink,
too. In no time at all, earth would be nothing more than a spherical ice ball
floating in space. [The late Isaac Asimov explored this far more eloquently
that I just did in one of his many short science articles...]

There are also about 9 different 'ices', called iceI, iceII, iceIII etc that
are beyond the scope of your question.

Answer 3

An unusual feature of ice frozen at a pressure of one atmosphere is that the solid is some 8% less dense than liquid water. Ice has a density of 0.917 g/cm³ at 0 °C, whereas water has a density of 0.9998 g/cm³ at the same temperature. Liquid water is most dense, essentially 1.00 g/cm³, at 4 °C and becomes less dense as the water molecules begin to form the hexagonal crystals of ice as the temperature drops to 0 °C. (In fact, the word "crystal" derives from Greek word for frost.) This is due to hydrogen bonds forming between the water molecules, which line up molecules less efficiently (in terms of volume) when water is frozen. The result of this is that ice floats on liquid water, an important factor in Earth's climate. Density of ice increases slightly with decreasing temperature (density of ice at −180 °C (93 K) is 0.9340 g/cm³).

When ice melts, it absorbs as much heat energy (the heat of fusion) as it would take to heat an equivalent mass of water by 80 °C, while its temperature remains a constant 0 °C.

Answer 4

Water expands when it freezes. That means that when water is converted to ice, it occupies more space but still weighs the same, therefore its density is less and so it will float on top of water.

Answer 5

Ice is less dense than water. This is due to the structure of the ice crystals formed when water freezes.

This is why ice cubes float, and icebergs float.

In fact water is the only (or one of the few - I can't be sure) matter that expands as it freezes to its solid state. This is how erosion works when freezing/thawing conditions occurs - as water freezes and expands, it widens the cracks in the rock that it sits in.

Answer 6

ice float on water is that a certain mass of ice occupies more space than the same mass of water. This is related to “hydrogen bonding”.

A water molecule is composed of two hydrogen atoms (H) and one oxygen atom (O). The atoms of hydrogen and oxygen are bound by sharing their electrons with one another. This bond is called a “covalent bond”.


However, since oxygen atoms pull electrons more strongly than hydrogen atoms, the oxygen atom in a water molecule has a slightly negative charge and the hydrogen atoms have a slightly positive charge. So adjacent water molecules are attracted to one another through the slightly negatively charged oxygen atoms and the slightly positively charged hydrogen atoms. This interaction is called “hydrogen bonding”. Hydrogen bonding is much weaker than covalent bonding, however, this type of bonding has a large total effect because there are so many hydrogen bonds.

Ice has a diamond structure due to the hydrogen bonding. Water does not have such an orderly structure, but water molecules are squeezed close to one another because of the hydrogen bonding.

Answer 7

Ice floats because it expands 11% when it freezes, making it less dense than water.

Answer 8

1ml of water weighs 1g.

1ml of ice weighs 0.92g.

Therefore ice has a lower density, you could not say that ice weighs less as if you had 2ml of ice and 1ml of water the ice would weigh more, but would still float.

Answer 9

Simply put without all the science dribble, when water freezes it expands. It's the only known sustance that reacts that way. This expansion makes frozen water less dense that liquid water--less dense meaning it weighs less per volume. So, it floats.

Answer 10

less density = less volume by mass
therefore the heavier mass sinks and the lighter mass floats
also the displacement factor allows ice to float