Thomas Chasteen's site ( http://www.shsu.edu/~chm_tgc/sounds/sound.html) shows how to separate colors using a tuneable monochromator. This graphic comes from his monochromator animation ( http://www.shsu.edu/~chemistry/monochromator/mono.gif).

Science Media's site ( http://www.scimedia.com/index.html#scimedia) includes spectroscopy tutorials by Brian Tissue. This graphic can be found at http://www.scimedia.com/chem-ed/light/graphics/em-rad.gif (©1998 B. M. Tissue, www.scimedia.com).

All the colors in the rainbow! Now that is a good place to start. Go to About Rainbows ( http://www.unidata.ucar.edu/staff/blynds/rnbw.html), a tutorial from astronomer Beverly Lynds, working with the University Corporation for Atmospheric Research. The tutorial begins with a historical perspective, complete with a sketch by René Descartes in 1637. The bibliography makes this tutorial a good starting point for color exploration. About Rainbows brings you questions to explorefor example, "What happens when you look at a rainbow through dark glasses?"

Try the links to these other sites. Project SkyMath: Making Mathematical Connections ( http://www.unidata.ucar.edu/staff/blynds/Skymath.html) is especially for the middle school student. Reproducible masters of these teaching modules can be printed in English and Spanish. From Project SkyMath, you can go to Blue-Skies, a user-friendly graphical interface from The Weather Underground at the University of Michigan ( http://groundhog.sprl.umich.edu/BS.html).

And speaking of blue skies, look at a great site, Why is the Sky Blue at http://acept.la.asu.edu/PiN/act/sky/sky.shtml. This is a super site from the Arizona Collaborative for Excellence in the Preparation of Teachers, by the Department of Physics and Astronomy at Arizona State University. If you go to Patterns in Nature: Light and Optics at http://acept.la.asu.edu/PiN/act/activities.shtml, plan to spend some time, for it is wonderful.

Another link from the About Rainbows tutorial goes to an experiment that is suitable for older students, Circles of Light--The Mathematics of Rainbows at http://www.geom.umn.edu/education/calc-init/rainbow/. Frederick J. Wicklin and Paul Edelman of the University of Minnesota note that this comprehensive lab is based on a module developed by Steven Janke.

Go back to About Rainbows to link to a Java applet, allowing you to change the incident angle and color of light striking a water droplet. This great teaching device is from Fu-Kwun Hwang of the National Taiwan Normal University at http://science.kongju.ac.kr/phys/shin/experiment/ntnujava /Rainbow/rainbow.html. And while you are here in this site (choose English or Chinese), look at the more than 30 Java applets created by F.-K. Hwang at http://science.kongju.ac.kr/phys/shin/experiment/ntnujava/index.html. The interactive applet on Shadow/Image and Color is great fun, (http://science.kongju.ac.kr/phys/shin/experiment/ntnujava/shadow /shadow.html).

From mixing colors, we can go to Thomas Chasteen's fine work at http://www.shsu.edu/~chm_tgc/sounds/sound.html for an animation (and movie also) of how to separate colors using a tuneable monochromator ( http://www.shsu.edu/~chemistry/monochromator/mono.gif). This colorful graphic, showing incoming parallel white light, is clipped from that monochromator animation. While you are here at this site at Sam Houston State University, look at the other great animations and movies, including a movie showing solution-phase chemiluminescence at http://www.shsu.edu/~chm_tgc/chemilumdir/movie.html.

So now that we have explored the breaking down of light into its component colors, we need to also look at another process--polarizing light. Let's go to Science Media's comprehensive site ( http://www.scimedia.com/index.html#scimedia) to examine polarized light ( http://www.scimedia.com/chem-ed/spec/molec/polarim.htm). Of course, most sunglasses polarize light--bringing us back to the question of the rainbow again. Explore here for a while--appreciate the beautiful visible electromagnetic spectrum at http://www.scimedia.com/chem-ed/light/graphics/em-visib.jpg. Great spectroscopy tutorials from Brian Tissue of the Virginia Polytechnic Institute and State University are found at Science Media's site. One of my favorite graphics ( http://www.scimedia.com/chem-ed/light/graphics/em-rad.gif) reminds us of why light is electromagnetic radiation.

But how to we actually see color? Go to the Access Excellence Classic Collection sponsored by Genentech, Inc. (http://www.gene.com/ae/AE/AEC/CC/). From here, go to How We See: The First Steps of Human Vision at http://www.gene.com/ae/AE/AEC/CC/vision_background.html. Here are good graphics and explanations of the roles of rod and cone cells, and lots more!

And marvel a little the next time you see a rainbow.

World Wide Web Addresses

About Rainbows
http://www.unidata.ucar.edu/staff/blynds/rnbw.html

Project SkyMath: Making Mathematical Connections
http://www.unidata.ucar.edu/staff/blynds/Skymath.html

The Weather Underground at the University of Michigan--Blue- Skies http://groundhog.sprl.umich.edu/BS.html

Why is the Sky Blue
http://acept.la.asu.edu/PiN/act/sky/sky.shtml

Patterns in NatureLight and Optics Activities
http://acept.la.asu.edu/PiN/act/activities.shtml

Circles of Lightthe Mathematics of Rainbows
http://www.geom.umn.edu/education/calc-init/rainbow/

The Physics of a Rainbow
http://science.kongju.ac.kr/phys/shin/experiment/ntnujava /Rainbow/rainbow.html

The NTNU Virtual Physics Laboratory
http://science.kongju.ac.kr/phys/shin/experiment/ntnujava /index.html

Shadow/Image and Color
http://science.kongju.ac.kr/phys/shin/experiment/ntnujava/shadow/shadow.html

Thomas Chasteen's Chemistry-Based QuickTime Movies, Animations, and Streaming Audio
http://www.shsu.edu/~chm_tgc/sounds/sound.html

Tuneable Monochromator
http://www.shsu.edu/~chemistry/monochromator/mono.gif

The Chemiluminescence Home Page
http://www.shsu.edu/~chm_tgc/chemilumdir/movie.html

Science Hypermedia Home Page
http://www.scimedia.com/index.html#scimedia

Polarimetry
http://www.scimedia.com/chem-ed/spec/molec/polarim.htm

The Visible Spectrum
http://www.scimedia.com/chem-ed/light/graphics/em-visib.jpg

Propagation Direction of Electromagnetic Radiation
http://www.scimedia.com/chem-ed/light/graphics/em-rad.gif

Access Excellence Classic Collection
http://www.gene.com/ae/AE/AEC/CC/

How We SeeThe First Steps of Human Vision
http://www.gene.com/ae/AE/AEC/CC/vision_background.html

access date for all sites: April 1999