Name: An Activity to Demonstrate Convection
Uploaded: 2019-07-19
Duration: 2 min 29 s
Description: Convection currents can have some fun effects. Here, we conduct an experiment demonstrating one of the effects of a convection current. Watch and learn.

Question

In very cold places, when the temperature becomes very low, the surface of lake freezes while the water inside does not. As a result, fish and other animals can still live in the lake. Can you tell why the water inside the lake does not freeze?

Accepted Answer

In very cold places, when the temperature becomes very low, the temperature of the water will also decrease. As the water cools, the density of water increases and the surface water sinks to the bottom and the bottom water rises up. This will continue until the whole water comes at $4$ degree Celsius.

Now, further cooling will occur, the surface water density will not increase; instead, the density decreases, which means that the surface water keeps on floating on the top. So, the surface water keeps on cooling until it gets converted to ice. As the ice is a bad conductor of heat, it keeps the inside water at a temperature of $4$ degree Celsius. As a result, fish and other animals can still live in the lake.

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