changes like burning of paper or plucking of leaves cannot be reversed (we cannot make paper from its ashes / we cannot join a plucked leaf back to the plant)
and hence known as irr-reversible change (chemical change).

changes like changing of ice into water or changing of water into vapour can reversed (by codensation and evaporation process) and hence are known as reversible change (physical change).

1 5 1
Changes that can be reversed :  Opening and closing of a door , filling water in a bottle , switching  on and off of light
Changes that can't be reversed : Growth of hight , ripening of fruit , cording of  milk