Why do rivers and lakes not freeze easily ?
Why do rivers and lakes not freeze easily ?
The river is large and to freeze them a large amount of energy is required. therefore it is very hard to freeze rivers.
Drop the temperature far enough, for long enough time, then rivers and lakes could freeze.
However, while water is moving, its temperature can drop below zero and it doesn't freeze. Obviously, faster moving rivers are less likely to freeze.
For lakes, water's unique density behaviour protects them from freezing. Unlike almost all substances, the solid form of water (ice) is less dense than the liquid form. Ice cubes float. (For almost all other substances, the 'cubes' would sink.)
So when lakes freeze, the ice stays at the top. This insulates the remaining water from the colder air above. If ice cubes sank, then lakes could freeze all the way to the bottom. The ice that formed would fall to the bottom, continually exposing the top water to the cold air.
The river is large and to freeze them a large amount of energy is required. therefore it is very hard to freeze rivers.
Drop the temperature far enough, for long enough time, then rivers and lakes could freeze.
However, while water is moving, its temperature can drop below zero and it doesn't freeze. Obviously, faster moving rivers are less likely to freeze.
For lakes, water's unique density behaviour protects them from freezing. Unlike almost all substances, the solid form of water (ice) is less dense than the liquid form. Ice cubes float. (For almost all other substances, the 'cubes' would sink.)
So when lakes freeze, the ice stays at the top. This insulates the remaining water from the colder air above. If ice cubes sank, then lakes could freeze all the way to the bottom. The ice that formed would fall to the bottom, continually exposing the top water to the cold air.
