Question

what are example of physical desirable changes?

Answer 1

Solubility of sugar and salt in water.  It is desired so we can drink beverages.

Melting of ice and cooling water or beverage, in which we put ice blocks.

Ductile material - like copper, aluminum -  change in shape to make utensils, wires.

water becoming steam vapor,  used in driving railway engines,  in generation of electricity.

Answer 2

Solubility of sugar and salt in water

Melting of ice

Melting of candle wax .