Rainbows Activity Page
From Connections, May-August 2011
Download and print this page to complete the activities and check out the bonus activities.
Have you ever seen rainbows on soap bubbles? Bubbles are too thin to have their own color, so any color you see on a bubble is being reflected from its surroundings.
When light intersects with the surface of a soap bubble, part of the light goes into the bubble and part is reflected off the surface. This causes the light to bend, or refract, off the inner and outer surfaces of the bubble wall, and we see different angles, or wavelengths, of color. This is also why we see rainbows on oil slicks.
Experiments with Bubble Rainbows
Set up some bubble solution and a blowing wand. You can make your own with one of the recipes (see below) or purchase a bottle of bubbles. Once you have bubbles to observe, look for the rainbows on the surface. Shine a flashlight directly on the surface of a bubble and you might see rainbow colors swirling on the surface until the bubble pops.
A flashlight, bubble solution, a clear plastic container lid, and a drinking straw.
- Turn on the flashlight and stand it straight up, pointing toward the ceiling.
- Place the lid on top of the flashlight so it makes a dish.
- Pour a small amount (about a tablespoon) of bubble solution onto the lid and spread it out evenly.
- Using the straw, blow some bubbles, and watch what happens. Hint: This works best in a darkened room.
Basic Bubbles: Mix 2 tablespoons of dish soap with 1 cup of water
Magic Bubbles (for thicker, longer-lasting bubbles): Combine 1 tablespoon of glycerin, 2 tablespoons of dish soap, and 9 ounces of water
Fun Facts about Extra Special Rainbows
- When sunlight reflects inside another rainbow’s raindrops, a double rainbow occurs.
- When rain is falling somewhere in the night sky, and light is reflected off a bright full moon, a rare lunar rainbow (or moonbow) may appear faintly in the opposite part of the sky from the moon.
- Fogbows—also called cloudbows or sea-dogs—are caused when light bounces off tiny atmospheric water droplets and appears as red and blue smears in the clouds.