Question

water expands on reducing its temperature below ______°c​

Answer 1

Water expands on reducing its temperature below 4°C.

This is called analomous behaviour of water.

Answer 2

Water expands on lowering the temperature below 4°C.

This phenomenon is known as the Anomalous Expansion of water.

Normally, water expands on increasing the temperature but it shows an abnormal behaviour below 4°C ( maximum density at 4°C). In between 4°C to 0°C, the water starts becoming less dense.It is because water generally forms open crystal structures in solid form.