as water cools down till 4 degrees celcius, water contracts. Below 4 degrees celcius, water expands. Why does this happen?
2006-09-10 00:55:58 · 5 answers · asked by crucio2_2005 1 in Environment
For most substances, the solid form of the substance is more dense than the liquid phase; thus, a block of pure solid substance will sink in a tub of pure liquid substance. But, by contrast, a block of common ice will float in a tub of water because solid water is less dense than liquid water. This is an extremely important characteristic property of water. At room temperature, liquid water becomes denser with lowering temperature, just like other substances. But at 4 °C, just above freezing, water reaches its maximum density, and as water cools further toward its freezing point, the liquid water, under standard conditions, expands to become less dense. The physical reason for this is related to the crystal structure of ordinary ice, known as hexagonal ice Ih. Water, gallium, bismuth, acetic acid, antimony and silicon are some of the few materials which expand when they freeze; most other materials contract. It should be noted however, that not all forms of ice are less dense than liquid water. For example HDA and VHDA are both more dense than liquid phase pure water. Thus, the reason that the common form of ice is less dense than water is a bit non-intuitive, and relies heavily on the unusual properties inherent to the hydrogen bond.
2006-09-10 00:59:02 · answer #1 · answered by Jason 2 · 2⤊ 0⤋
When water freezes, it's molecule push apart into a triangle struture. Because the Hydrogen molecule is positive it repels to 2 Oxygen molecules. The way they are stacked needs some space, just like the space that would be between two magnets that are both positive.
2006-09-10 03:49:38 · answer #2 · answered by Anonymous · 3⤊ 0⤋
As water molecules approach each other, their shape causes them to be packed in such a way that the net energy of the system is minimised. Since water molecules bond to each other strongly due to hydrogen bonds, it also plays a decisive role. A lattice emerges which has a lot of voids. Thus water expands as it forms ice.
2006-09-10 01:40:49 · answer #3 · answered by ag_iitkgp 7 · 3⤊ 0⤋
The particals that make up water are not as packed to gether as solid so when water turns to ice its a solid so the particals are more packed to gether
2014-11-25 18:30:31 · answer #4 · answered by Anonymous · 1⤊ 0⤋
awesome question..........thanx!
2006-09-10 02:02:57 · answer #5 · answered by questiongirl14 2 · 1⤊ 1⤋