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.
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.