Science Experiments for Kids: Fun with Light and Visual Illusions

Science experiments are a fun and easy way for kids to learn about cool scientific principles without getting bored. In this article, I'll detail a few more science experiments that are simple to do, and teach your child all about the wonders of light and visual illusions.

Experiment 1: The Amazing Pencil

What you'll need:
A glass jar (rounded, like a peanut butter or jelly jar)
1 Pencil
Water

Step One: Fill the jar to the brim with water, and place the jar on a table.
Step Two: Stand a pencil about one foot (about 30.5 cm) behind the jar. When you look at the pencil through the jar, it seems to have doubled! If you want to be even more amazed, close your left eye and watch as the pencil on the right-hand side disappears. Now close your right eye and watch the left-hand pencil vanish!

Why does it work?
The water allows objects to be seen smaller than they actually are, and since the jar is a cylinder, you are able to view the pencil from all directions. Each of your eyes views the pencil through the jar at a slightly different angle, each seeing a smaller image, so when the two angles combine, a second pencil appears. Likewise, as you close each eye, you are limiting your view to only one angle (and therefore one pencil).

Experiment 2: Ghost Orb

What you'll need:
Your own hands (yes, this experiment requires practically nothing!)

Step One: Hold up your two pointer fingers (so it looks like you are indicating the number one), then turn them so that the fingers are facing each other. Right now, it should look as though your fingers are pointing at one another, with the fingernails facing away from your eyes.
Step Two: Touch the fingers together, and hold them about a foot (about 30.5 cm) in front of your nose. As you look over your fingertips, a ghostly ball will seem to appear between them!

Why does it work?
As you look over the top of your fingers, your eyes become focused on whatever is in front of you. Your fingers are then projected on your retinas in a way that makes your brain process the fingertips as doubled. Your brain then combines the double fingertips, making it appear as though there is a ball floating between your fingers.

Experiment 3: Color Spinning

What you'll need:
A piece of heavyweight paper
Markers (red, orange, yellow, green, light blue, violet)
Scissors (have an adult help with the cutting if necessary!)
An old spinning top

Step One: Cut out a circle from the heavyweight paper. The disc should be anywhere from 4-6 inches (10-15 cm) in diameter.
Step Two: Color 6 wedges of the circle in the following order: red, orange, yellow, green, light blue, violet. The disc should now be completely colored.
Step Three: Make a hole in the center of the disc (if you have a hole punch this step is very easy!).
Step Four: Push the disc over a a spinning top, and give it a whirl. The colors will seem to disappear, and the disc will look white!

Why does it work?
The colors that you put on the paper disc match the sunlight spectrum (red, orange, yellow, green, light blue, violet). As the disc spins, our eyes are unable to distinguish the individual, rapidly changing colors. It is because of our relatively slow eye responses that the individual disc colors are translated in the brain as being an entire circle of white.

Experiment 4: Mystery Shadow

What you'll need:
A glass
Vinegar
Baking soda

Step One: Turn on a light, or position yourself in front of a sunny window, while standing in front of a lightly colored wall. You need to be casting a shadow for this experiment to work.
Step Two: Pour some baking soda into the glass. I usually use a few tablespoons.
Step Three: Pour in some vinegar, and tilt the glass away from you, being careful not to spill the vinegar. You may not be able to see the gas with your naked eye, but look at the wall. You will see dark and light clouds flowing and swirling as a shadow!

Why does it work?
The carbon dioxide that is given off by the vinegar and baking soda mixture has a different optical density than the surrounding air. So when the light rays hit the carbon dioxide gas, the rays are bent - the light clouds are where the light is refracted towards the gas, and the dark clouds are where the light rays are bent away from it.