Joey Green's Mad Scientist

Cosmic Ray Detector

What You Need

Scissors
Black heavy felt
Clean, empty glass jar with a rubber washer or cardboard filler under the lid
Ruler
Rubber cement
Black velvet
Rubbing alcohol
Two towels
Pie tin
Rubber gloves
Block of dry ice (enough to fill the pie tin)
Hammer
Ice tongs
Flashlight
Three books
Masking tape
Small magnet

What to Do
Cut the felt in a circle to lie in the bottom of the jar. Glue the felt in place with rubber cement. Cut a strip of felt 1 inch wide and glue it around the inside wall at the bottom of the jar.
Cut a strip of velvet 1 inch wide and glue it to the top of the jar's inside wall. Cut a circular piece of velvet to fit inside the metal lid, over the rubber or cardboard, and glue it in place.
Pour enough rubbing alcohol into the jar to saturate the felt at the bottom of the jar thoroughly and cover the bottom of the jar. Screw the lid on the jar tightly and let it sit for ten minutes.
Spread a towel on a flat surface and place the pie tin on top of it. Wearing rubber gloves (to avoid touching the dry ice with your bare hands), wrap the second towel around the block of dry ice, then break up the block with the hammer. Using the ice tongs, put the cubes of dry ice into the pie tin, making a level surface on which to place the jar.
Turn the jar upside down and place it on the dry ice in the center of the pie tin.
Position the flashlight on top of the books, attaching it in place with masking tape, aiming the beam through the lower half of the jar. Turn off the lights, and cover the bottom of the jar with the palm of your hand to warm the alcohol soaked velvet. Watch carefully.

What Happens
Within five minutes, the alcohol vapor condenses, warmed by your hand, and you'll see a continuous rain of fine mist 1 inch below the top of the chamber. After another five minutes, the rain decreases.
When the interior temperature is just right, you see cobweblike threads suddenly appearing and disappearing at various angles about an inch above the lid. These are vapor trails made by cosmic rays passing through the jar. Place the magnet against the side of the jar, and the trails will be deflected toward it.

Why It Works
The heat from your hand warms the top of the chamber, and the dry ice cools the bottom of the chamber. Somewhere between these temperature extremes, usually about 1 to 2 inches from the bottom, the air becomes saturated with alcohol vapor, and particle trails become visible where cosmic rays cause the alcohol to condense.

Bizarre Facts

Cosmic rays are high-energy particles that originate from explosions in outer space—from phenomena such as supernovas and pulsars. At this very moment, cosmic rays are hurtling through space at nearly the speed of light.
Trillions of these particles pass through the earth's atmosphere every few minutes.
Three to six cosmic ray particles strike each square inch of the earth's atmosphere every second.
Cosmic rays are penetrating your body at this very moment.
Physicist Murray Gell-Mann named the subatomic particles known as quarks after a line from James Joyce's novel Finnegans Wake: "Three quarks for Muster Mark!"
The common goldfish is the only known animal that can see both infrared and ultraviolet light.
Adolf Hitler, refusing to accept the fact that a Jew had come up with the theory of relativity, falsely claimed that Albert Einstein had stolen the idea from some papers found on the body of a German officer who had been killed in World War I.

Cosmic Gilligan
When a meteorite hits Gilligan's Island, the Professor, after measuring the meteorite with a bamboo Geiger counter, claims: "There were cosmic rays, which aren't as deadly as interstellar radiation; however, they can kill you." The Professor is just plain wrong. Cosmic rays are a form of radiation that is far too weak to endanger anyone.

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