Sunday, March 15, 2009

Science: Color and Vision

Last week we took a slight detour from our science and art color study to explore color and vision. We finally got to try the Bird in a Cage experiment from one of my new favorite experiment sights, Exploratorium Science Snacks. Not snacks for the tummy, snacks for the brain! Quick and simple science experiments, complete with thorough explanations. Perfect for filling 15-20 minutes.

You need:
Posterboard or thin cardboard (Scraps work just fine.)
Colored paper--red, blue and green
White paper
Pencil and scissors
Black marker
Bright light--Try this on a sunny day for best results!

Draw a silhouette of a favorite animal onto the posterboard. Cut it out and use it as a template to trace your animal onto the red, blue and green papers. Cut out your colored animal shapes and glue them to your white paper. (We used the science notebook pages.) On another white paper, draw a birdcage, jungle, or other habitat for your animal using the black marker. Place your pages in bright light and stare at one colored animal for about 30 seconds. Then stare at your cage (or other habitat). What do you see?

You should see an afterimage, a colored image of your bird. Your white paper reflects blue, red and green light. You've tired the cones in your eye sensitive to the color at which you've been staring, so you see the other colors more strongly. If your red-perceiving cones are tired from staring at the red bird, for example, the blue- and green-perceiving cones are stronger, so you should see more blue-green light bouncing off the page, which creates a blue-green afterimage.

A common variation on the afterimage experiment uses the American flag. Create an American flag using black and green stripes, and black stars on an orange background. (Directions here.) After staring at your flag, then directing your eyes to a white page, you should see the traditional red, white and blue American flag.
3D Stereograms: Magic Eye

Magic Eye, by Magic Eye, Inc.
Check Magic Eye books out of the library. They will keep the kids entertained for what seems like hours. It's fun snuggling on the couch staring at the pages, trying to get the seemingly random patterns on the page to pop out into 3D pictures. Having trouble? Read this: How to see 3D for an explanation of how it works.

Then make your own stereograms online:
Create your own 3D stereogram
This application lets you draw your own picture and choose your colors. We're having a blast with this. The fine young gents drew their names and printed their personal stereograms to paste into their science notebooks.

Choose from different backgrounds and pictures at Easy Stereogram Builder. (The stereogram above was created using this site.) Then read about how they work. There's a great explanation of stereo vision here: What is Stereo Vision?

We love Bill. Watch Bill Nye the Science Guy: Light and Color for some color and light science fun.

"Bill! Bill! Bill! Bill!"

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