Why does a lake freeze from the top down?

Question

Quizplus · Accepted Answer

As water cools down, it becomes less dense until it reaches its maximum density at 4°C (39.2°F). As the water temperature drops below 4°C, the water molecules start to form into a crystalline structure and the ice begins to form on the surface. The ice continues to form downwards as long as the temperature is below freezing, with the coldest water sinking to the bottom while the warmer water rises to the top. Therefore, the lake freezes from the top down.

Why Does a Lake Freeze from the Top Down