Adding or removing energy from matter causes a physical change as matter moves from one state to another. ... Physical changes can also be caused by motion and pressure. Melting and freezing. When heat is applied to a solid, its particles begin to vibrate faster and move farther apart.
Adding energy (heat) to liquid water causes it to become steam or vapor (a gas). And removing energy from liquid water causes it to become ice (a solid).
I hope you're talking about science lol but I forgot to check the subject. Hope this helps.
well try talking to him first and being his friend. introduce yourself and try not to be too awkward or shy. can't reltate lol. after that if he really likes you, he'll initiate stuffs ^^