Question

During summers in India, one of the common practice to keep cool is to make ice balls of rushed ice, dip it in flavoured sugar syrup and sip it. For this a stick in inserted into crushed ice and is squeezed in the palm to make it into the ball. Equivalently in winter, in those area where it snows, people make snow balls and throw around. Explain the formation of ball out of crushed ice or snow in the light of P-T diagram of water.

Answer 1

Refer to the P-T diagram of water and double headed arrow. Increasing pressure at 0ºC and 1 atm takes ice into liquid state and decreasing pressure in liquid state at 0ºC and 1 atm takes water to ice state.

When crushed ice is squeezed, some of it melts, filling up gap between ice flakes, upon releasing pressure. This water freezes, binding all ice flakes making the ball more stable.