Man am I confused

[DB]

I'm confused, does heat cause vibration in molecules or do virbrating molecules cause heat? I have heard both stated. I just dont understand what heat is.

Ty

[Gonzolo]

Hi, heat is the flow of energy from a higher temperature medium to a colder temperature medium.

Both of your situations can be correct. If the molecules are in a colder medium, they will cause heat in the medium. If the medium is hotter, its heat will cause the molecules to vibrate.

BTW, this is more classical physics, not quantum.