WHY DOES ICE FLOAT ON WATER?

ANTARCTIC ICE FLOATING ON WATER [NSIDC]

When a substance is less dense, or has less mass per unit volume, it floats than other elements in a mixture. For example, if you throw a handful of rocks into a bucket of water, the rocks that are dense in comparison to the water will sink. The stream, which is less solid than the surface, is going to float. Basically, the rocks force the water out of the way, or they displace it. In order for an object to be able to float, it must move a fluid weight equal to its own weight.

Water reaches 4 ° C (40 ° F) to maximum density. As it cools down further and freezes into ice, it becomes less dense indeed. On the other hand , the majority of substances in their solid (frozen) state are more dense than in their liquid state. Because of the hydrogen bonding water is different.

A water molecule is composed of one oxygen atom and two hydrogen atoms with covalent bonds that are tightly joined to each other. Water molecules are often drawn to each other by weaker chemical bonds (hydrogen bonds) between the positively charged hydrogen atoms of adjacent water molecules and the negatively charged oxygen atoms. The hydrogen bonds change to keep the negatively charged oxygen atoms apart, as the water cools down to below 4 ° C. This gives rise to a crystal lattice usually called ice.

Ice floats because it is less dense than liquid water around 9 per cent. In other words, ice takes up approximately 9 per cent more space than water, so a liter of ice weighs less than water. The lighter ice is displaced by the heavier water, so ice floats upwards. One result of this is that from top to bottom lakes and rivers freeze, allowing fish to thrive even after a lake ‘s surface has frozen over. When ice sinks, the water would migrate to the surface and be exposed to colder conditions, causing rivers and lakes to fill with ice and strong freezing.

In heavy Water Ice Sinks!

Not all water ice floats at regular water, however. Ice made from heavy water, containing the Deuterium hydrogen isotope, sinks in regular water. Hydrogen bonding also exists but it is not necessary to reduce the difference in mass between normal and heavy water. Under hot water the warm water ice melts.

A special thanks to Anne Marie Helmenstine and thought and co