Penny asks Sheldon for advice on whether or not she should date Leonard, and during the conversation, Sheldon corrects her use of physics terms. He then explains the Schrödinger's Cat thought experiment to help her think about the situation.

Sheldon is in the car on a road trip with his dad and brother. They are talking about roadkill, and his dad asks if it's alive or dead if it's still twitching. Sheldon mentions that it sounds like Schrodinger's Cat and explains the theory.

In this clip, Leonard explains on the radio how the Large Hadron Collider is being used to find subatomic particles like neutrinos.

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.

Mr. Seaver begins teaching the class a lesson on gravity out of the textbook. He is especially confused by the book's claim that a coin and a feather will fall at exactly the same speed. After Luke challenges him to prove it, he tests the claim.