Sheldon dresses up as the Doppler Effect for Penny's Halloween party. When Penny asks about his costume, Sheldon explains the Doppler Effect to her.

Cole Trickle performs his first ride around the racetrack and finishes with an impressive time. As the car travels around the track, the sound of the motor changes in pitch.

A series of simple machines help collect mushrooms and crush them to produce a drink for Dr. Robotnik.

Bill Nye show us how a circuit works by comparing electrons to water.

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.