Joey Green's Mad Scientist

Swinging Cups

What You Need

Two chairs
Thin rope
Ruler
Scissors
Two coffee cups

What to Do
Place the chairs back to back 3 feet apart. Tie a piece of the rope from the top of one chair to the top of the other.
Measure and cut two pieces of thin rope 24 inches long and tie a coffee cup to the end of each rope. Tie the free ends of the ropes to the rope between the chairs, letting the coffee cups hang 20 inches apart from each other and equidistant from the chairs. Move the chairs so that the center of the horizontal rope sags about 4 inches below the spots where the cord is tied to the chair backs.
Start one of the cups swinging at right angles to the horizontal cord like a pendulum.
Tell your audience to watch closely. Insist that by using your hypnotic energy, you will make the first cup stop swinging and the second cup start swinging. Wiggle your fingers toward the cups. The first cup slows down until it stops completely while the second cup begins swinging. A moment later, wiggle your fingers toward the cups again. The second cup will stop swinging and the first one will begin swinging again.

What Happens
While you pretend to be controlling the cups hypnotically, the motion continues being transferred from one cup to the other as long as the cups keep swinging.

Why It Works
Pendulums attached to a central line transfer energy back and forth between themselves through the connecting line.

Bizarre Facts

Galileo Galilei first demonstrated this effect in 1583.
At age twenty, Galileo discovered the law of the pendulum by timing the swings of a bronze lamp that hangs from the ceiling in the cathedral in Pisa, Italy. He observed that each swing took the same time, whether the arc was large or small.
Edgar Allen Poe, author of The Pit and the Pendulum, married his cousin Virginia Clemm when she was not quite fourteen years old.

Worlds Largest Yo-Yo
On March 29, 1990, the woodworking class of Shakamak High School in Jasonville, Indiana, launched a yo-yo measuring six feet in diameter and weighing 820 pounds from a 160-foot crane. It yoyoed twelve times. The word yo-yo means "come-come" in Filipino, and the toy purportedly originated in the Philippines as a weapon.

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