When you think of Molecular Theory, you are like, AAAAAHHHHHHH! That is like totally advanced science stuff. But really, it's not. Molecular Theory is just about solids, liquids, gases, and atoms basically. Molecular Theory is learning that all atoms in all substances vibrate, nothing can reach Absolute Zero. Absolute Zero is when it is so cold, the atoms don't even move. Which is impossible. Molecular Theory is hard to explain, so just call my science teacher for more information. (: