Non- Reversible changes= Changes which cannot be reversed are called non- reversible changes. It is also called chemical changes. For example Burning of thread.
Reversible changes= Changes which can be reversed are called reversible changes. It is also called physical changes. For example melting of ice.
Reversible change sr those changes that can restore their previous state or condition. Like water turning to ice. R mostly physical changes............. Non Reversible changes r those which cannot restore their previous state. They have undergone a chemical change. Once this change happens it cant b altered back to its previous condition. Like burning a paper. These r mostly chemical changes..... :)