Question

Do we always need to supply heat or change the pressure for changing the state of matter?

Answer 1

I think the answer should be no. At the molecular level, the change of state of matter occurs due to the increase in kinetic energy of the molecules to an extent that they are able to overcome the intermolecular forces between nearby molecules.

Now generally heat energy is used to increase the kinetic energy and hence change the state. However , even other forms of energy like sound energy should also work provided the intensity is strong enough to increase the KE of the molecules to the required value.