Explain how does anomalous expansion of water helps in sustaining the life of plants and animals living in lakes and ponds during winter season?
The anomalous expansion of water helps preserve aquatic life during very cold weather. When temperature falls, the top layer of water in a pond contracts, becomes denser and sinks to the bottom. A circulation is thus set up until the entire water in the pond reaches its maximum density at 4°C. If the temperature falls further, the top layer expands and remains on the top till it freezes. Thus even though the upper layer are frozen the water near the bottom is at 4°C and the fishes etc. Can survive in it easily.
Hope this helps.
Regards
Learm CBSE