Question

When surface water in a lake is just going to freeze, then what is the temperature of water at the bottom?

• A. Less than $0^{\circ }$
• B. $0^{\circ }$
• C. $4^{\circ }$
• D. More than $4^{\circ }$

Answer 1

The correct option is C $4^{\circ }$

Water achieves it maximum density at roughly $4^{o}C$,i.e. water (including ice) at all other temperatures below or above $4^{o}C$ is less dense. Since matter is ordered from top to bottom by increasing density, any $4^{o}C$ water in a lake will be found at the bottom.