Explain anomalous behaviour of water. Write its effect in lakes and ponds.

Explanation

i. Liquids expand on heating and contract on cooling.
ii. But water exhibits an exceptional behaviour in temperature range of `0^(@)C" to "4^(@)C` . iii. When water is heated from `0^(@)C" upto "4^(@)C` , instead of expanding it contracts. Its volume decreases continuously from `0^(@)C" to "4^(@)C` .
iv. At `4^(@)C`, its volume is minimum.
v. Upon heating further, however, it expands and its volume increases .
vi. This behaviour of water between temperature interval of `0^(@)C" to "4^(@)C` is called anomalous behaviour of water.
vii. Phenomena observed due to anomalous behaviour of water are:
a. Survival of aquatic life in cold regions,
b. Cracking of rocks in winter,
c. Breaking of pipes for water supply in cold region.