Exploring Light

This session introduces light waves and how light arrives on our planet after a speedy trip from the Sun (93 million miles away). We learn the primary colors of light: Red, Green and Blue and how when the lights overlap the secondary light colors of Magenta, Cyan and Yellow are revealed. Color is one of the strangest things about light. Sunlight isn’t light of just one color—it’s what we call white light, made up of all the different colors mixed together. We know this because we can see rainbows, those colorful curves that appear in the sky when droplets of water split sunlight into its component colors by refracting (bending) different colors of light by different amounts.

Make a Rainbow in Water/Prisms:  When light passes through a prism, it separates into the colors that make it up. White light changes to a swath of colors. This rainbow is called a spectrum. You can make spectra (the plural of spectrum) in many ways: with a prism, with drops of water (as in a real rainbow), or with gratings (like in the glasses you can get).

Experiment with Primary Colors of Light: Get 3 flashlights and put a color filter over each: 1 blue, 1 red and 1 green. In a dark room on a white wall have children shine the flashlights to overlap the colors until a white light appears. Ask the children to put their hands under the lights and their shadows reveal the secondary light colors: Magenta, Cyan and Yellow.

Experiment with Light and Mirrors: When you look at a mirror and see your face reflected, what’s actually going on? Light (maybe from a window) is hitting your face and bouncing into the mirror. Inside the mirror, atoms of silver (or another very reflective metal) are catching the incoming light energy and becoming excited. That makes them unstable, so they throw out new photons of light that travel back out of the mirror towards you. In effect, the mirror is playing throw and catch with you using photons of light as the balls!