Joey Green's Mad Scientist

Underwater Candle

What You Need

Utility knife
Corrugated cardboard box (roughly 1-1/2 by 2 feet wide and 1-1/2 feet high)
Piece of corrugated cardboard (roughly 1-1/2 by 2-1/2 feet)
Ruler
Pencil
Newspaper
Paintbrush
Flat black tempera paint
Clear packaging tape
Glass from a picture frame (about 8 by 10 inches)
Candle
Drinking glass
Matches
Pitcher
Water

What to Do
With adult supervision, use the utility knife to carefully cut the flaps from the top of the box, and fit the long piece of cardboard snugly upright diagonally inside the box (from the front left-hand corner to the back right-hand corner), dividing the box equally into two triangular halves.

Carefully measure and cut a small viewing window (6 inches square) in the front left half of the box where the dividing cardboard meets the corner.

Remove the divider from the box and cut a window about 7-by-9 inches that will line up with the window on the box, allowing you to look straight through to the left rear side of the box. Spread newspaper on the tabletop and paint the divider and the inside of the box with the flat black tempera paint. When the paint is dry, use the packaging tape to secure the 8-by-10-inch glass over the opening in the divider. Place the divider back in the box.

Mount the candle in the center of the first compartment. Place the drinking glass in the center of the rear compartment. Light the candle. Look through the viewing window and through the glass window. Align the candle and the glass until the candle appears in the center of the glass.

Have a friend look through the viewing window. Slowly pour the pitcher of water into the empty glass in the rear compartment.

What Happens
Your friend sees a candle burning in a glass of water.

Why It Works
The light reflecting from the front of the glass window reflects the image of the candle in the glass. This optical illusion is created because you can still see through the window to the glass with the water.

Bizarre Facts

This optical illusion is used in circus sideshows to create the illusion of a human turning into a skeleton or monster.
In 1862, after fifteen years of work, French physicist Jean Foucault used a candle and two mirrors to measure the speed of light at 187,000 miles per second. Modern methods have refined the figure to 186,282 miles per second.
Our eyes remain the same size from birth, but our nose and ears never stop growing.
An ostrich's eye is bigger than its brain.

It's a Bird, It's a Plane
In comic books, when Superman uses his X-ray vision to see through concrete walls, X rays shoot from his eyes. Living creatures do not see by radiating light from their eyes. (X rays are a more energetic form of light.) Instead, light enters the eye, is refracted by the cornea, passes through the pupil, is refracted by the lens, and forms an image on the retina, which is rich in nerve cells that are stimulated by light. To see through concrete walls, the nerve cells in Superman's retinas would have to be stimulated by X rays.

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