Question

when water freezes its volume increases or decreases

Answer 1

When water freezes its density will decrease.
Because of anomalous expansion of water the water expands instead of contracting from 4 degrees Celsius to 0 degrees Celsius.this id an abnormal property of water.As volume is inversely proportional to density when the volume of water increases the density decreases.
Hence proved that when water freezes its density decreases.