Video narration
How can boiling water, dissolving salt, and baking belong to the same story? Chemistry starts with matter: anything that has mass and takes up space. When water boils, only its state changes; it is still water-a physical change. When baking produces new substances, that is a chemical change. Now classify what you handle. An element is one kind of substance. A compound is different elements chemically joined. A mixture contains substances together without forming a new substance. Here's the turn: to explain what substances are, we zoom in. Matter is built from tiny particles called atoms. A chemical formula uses symbols and numbers to show which atoms, and how many, are present. So the first five lessons form one path: start with matter, examine changes, classify substances, then use atoms and formulas to describe them. They belong together: follow matter from change to formulas through atoms.