Beakman demonstrates that marshmallows are less dense than the same amount of water and therefore, marshmallows float. Nails are heavier than the same amount of water so they sink. He then explains water displacement by getting into a tank of water. His DIY demo for this is making a aluminium boat that floats in a bowl of water but when you crush the aluminum foil into a square, it sinks because it couldnt' displace the water.
This video gives an example of someone trying to find the height of their bedroom by using acceleration and velocity. This also incldues an explanation of the different aspects of integrals, velocity graphs, displacement curve, integral of acceleration, and the power rule in order for someone to solve the example. Additionally, the Crash Course video explains how to use constants in the equation.
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).