Beakman explains density by weighing out different volumes of different items. He then shows how a balloon filled with helium is less dense than one filled with our own air so therefore it rises.

In an attempt to collect the Golden Idol, Indiana takes the idol and replaces it with a bag of sand the same size. That doesn't work, as the traps still activate, and Jones needs to escape quickly or meet his fate.

Galileo explains to his student that, if two balls are dropped at the same height, they will both hit the ground at the same time, regardless of their weight.

Professor Anderson leads the group through the underground cave. He almost falls down a deep chasm as he tries to assure the group that he's good with directions. He attempts to use a flare to measure the depth of the chasm, but the magnesium rocks cause it to explode. Hannah then gives him a glowstick, and he uses that to determine that the chasm is about 200 feet deep.

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.