Each learning path is one chapter: a guided route through a topic, one small course at a time. Pick a class to see its chapters in order.
Look around you. A stone, a glass of water and the air that you breathe are all matter, and they are very different. Why is a stone hard, water runny and air invisible? In this chapter we study the tiny particles that matter is made of. We find how they explain the solid, liquid and gas states, how ice melts and water boils, and why wet clothes dry and sweat cools us. Python helps us with the calculations.