John discusses the US' industrial revolution and the extremely wealthy individuals who profited off the era. They were either seen as "robber barrons" or "captains of industry" because they controlled much of the US' money and held the largest companies in the world.
Beakman explains what metals are and how they occur naturally. He then pretends to be Andrew Carnegie to explain how he figured out how to make steel. Beakman explains that steel is a lot stronger than iron so this allowed us to create buildings, strong machines, etc.
Sheldon tries to make friends by following the principles that Dale Carnegie has outlined in his book, "How to Win Friends and Influence People." His conversations are robotic, not authentic, and awkward as a result.