Special Relativity – 7F10.00

Equivalence Principle – 7F10.10


  • A long broomstick has a cup attached to the end.
  • Inside the cup are a ball and a weak spring.
  • When the ball hangs out of the cup the spring is too weak to pull it back in.
  • When the stick is raised up in the air and released gravity is instantly switched off.
  • In the absence of gravity (freefall) the weak spring has the ability to pull the all back into the cup.

This apparatus is also called Einstein’s Toy. It was designed by Eric Rogers of Princeton and presented to Einstein on his 76th birthday.

Location: Jacobs B122 – Shelf 284

Geodesics – 7F10.20

Geodesics 1- 1T10.10

Geodesics 2- 1T10.10

  • This demo shows how a curve is the shortest distance between two points in a curved space.
  • Two points on a globe are connected by a straight line and another one curved going through the arctic.
  • Both distances are measured.
  • The distance connected through the arctic is shorter.

Location: Jacobs B122 – Shelf 278