In this Science Max Quiz, Phil explains how to differentiate chemical and physical changes. He mentions that chemical changes produce new molecules, while physical changes don't. He includes several examples of both physical and chemical changes.
This clip explains how drinking alcohol actually makes you drunk. When the molecules that make up alcohol enter your body, they change the chemical makeup and react with different parts of your body that ultimately makes you feel "drunk."
Bill Nye is obssessed with erosion and explains that rocks change over time. He explains what causes weathering (although he calls it erosion): water, ice, wind, sand, and chemicals. He illustrates the process of erosion in his lab.