Beakman explains what a chemical reaction is and then shows examples of three kinds of reactions which he explains are like partnerships: synthesis (marriage), decomposition (divorce), and double displacement (do-si-do).
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.
Walt suggests to Jesse that they have finished their work for now because the reaction has begun. After Jesse asks Walt how long the reaction will take, Walt explains why having a freezer would speed up the reaction: because it's exothermic.
A fire investigator and a fireman are at the scene of an incident involving fire. The investigator explains how the backdraft likely occurred and starts a fire to illustrate to the fireman how a fire starts and spreads. He states that fire is a living thing, as it breathes and eats, and suggests that fire needs to be respected if you want to beat it.