I really love reading about lectures like this. If you ask me, we can really learn a lot from reading this type of material. Well, it is not as complex as most are, but they really went hard on trying to explain the concepts of solid and liquid. Sure, there are far more better material for learning, but at the end of the day, it is about what you understand. I feel like this is better than most in terms of understandability.
Good reading this post