Question

A glass of water is kept in a freezer. Why it starts freezing from upper surface and melting from bottom?​

Answer 1

Answer:

Below 4° Celsius, water becomes less dense as it gets colder, causing water about to freeze to float the top because the same mass of molecules takes up more space when frozen, ice is less dense than liquid water. For this reason, water below 4° Celsius becomes increasing less dense as it gets colder.