Aword meaning drastic change from the old way ; toppling the old and building a new way

That word is revolution. It is a word first used to describe the toppling of the monarchy in England during the English Revolution and that became instantly associated with the overthrowing of a tyrannical and despotic government by the masses of citizens after the American Revolution and the French Revolution.

a. theta waves. this is because the person is in a light sleep which means the brain waves would show these kind of waves.