Let’s Make Rainbows
There are a variety of lessons which can be learned using rainbows. Rainbows are the essential tool for teaching ROYGBIV. You can also use rainbows to demonstrate the difference in primary pigment colors versus primary colors of light. Below is an exercise demonstrating the primary colors of pigment.
Rainbow in a Bag
You will need:
Red, yellow and blue food coloring
1/3 cup sugar
1 cup cornstarch
4 cups cold water
Medium sized pot
3 bowls
3 “Ziplock” style bags- preferably ones made of thicker plastic
1. Mix the sugar and the cornstarch together in the pot. Make sure they are thoroughly blended.
2. Add the water and stir.
3. Cook the mixture over medium heat, stirring continuously until the mixture thickens, about 5 - 10 minutes.
4. Divide the mixture evenly into your three bowls. Add a few drops of food coloring to each bowl creating three different colors. Mix well. Add enough food coloring to make vibrant colors. Let the mixtures cool.
5. Put a large spoonful of each color into the plastic bag. Seal the bag carefully. Smoosh the mixture together using your finger. The colors will begin to blend creating all the colors of a rainbow. Eventually, the colors will blend to the extent that the mixture will turn gray. No problem - you have 2 more bags, so you can start the fun all over again!
Make a Rainbow Indoors
What you will need:
A glass of water
A mirror small enough to fit inside your glass
Flashlight
A dark room with white or pale colored walls
1.)Fill your glass all the way to the top with water.
2.)Insert the mirror and tilt it diagonally so the mirror points upward
3.)Place the glass in a very dark room and point your lit flashlight directly at the mirror inside the glass. A rainbow should appear on the wall. If you have problems producing a rainbow try to adjust the angle of the mirror.
Explanation- As light passes through the water, the water refracts the light causing the colors to separate.

Filed under: Science, Arts & Crafts on March 28th, 2007 | No Comments »







