T H E   N I H    C A T A L Y S T    M A Y  – J U N E    2005


If you have a photo or other graphic that reflects an aspect of life (including laboratory life) or a quotation that scientists mightappreciate that would be fit to print in the space to the right, why not

send it to us via e-mail:

<catalyst@nih.gov>; fax: 402-4303; or mail: Building 2, Room 2E26.

Also, we welcome "letters to the editor" for publication and your reactions to anything on the Catalyst pages.


In Future Issues...

More Bench to Bedside

Getting Control of IBD

IG Inventory

The NIH Catalyst is published bi-monthly for and by the intramural scientists at NIH. Address correspondence to Building 2, Room 2E26, NIH, Bethesda, MD 20892. Ph: (301) 402-1449; fax: (301) 402-4303; e-mail: <catalyst@nih.gov>.

Kids' Catalyst


A rainbow is a fantastic sight. It’s the momentary convergence of light, water vapor, and angles, and can all be explained by math (which you’ll encounter soon enough). Actually, the mathematical explanations themselves are beautiful, though not in the way of a rainbow.

Fortunately, you don’t need to stare at the sky just waiting for things to fall into place for the perfect rainbow—you can create your own, observe reflection and refraction, and make your own rainbow dance.

For this experiment, you will need:

A sunny day

A white piece of paper taped to a piece of cardboard

A mirror small enough to fit into a shallow dish

A shallow dish


Your favorite set of crayons, colored pencils, or watercolors (not at all optional!)

Fill the shallow dish about three-quarters full of water. Place the mirror in the dish at an angle such that some of the mirror is in the water and some of it is not. (You need the light from the sun to shine through the water and catch the reflection of the submerged mirror.) Take the paper (taped to the cardboard because light would shine right through just a plain piece of paper) and hold it up to the reflection the mirror makes. The reflection of the portion of the mirror not in the water will appear as a bright white spot on your piece of paper, but if you move the paper to see the reflection of the mirror that is inside the water you get your rainbow!

If you are doing this experiment using a window, tape the paper to a sturdy surface and draw what you see. Just a few changes you can make and observe are:

How does the intensity of the rainbow’s colors change when the angle of the mirror changes?

How does your rainbow look when you step away?

What changes when you add red food coloring to the water? What about blue? Green? (You could, of course, use your watercolors, but depending on the size of your dish, this could use quite a bit of your lovely watercolors. . . stick with the food coloring for quick results.)

Have fun with your rainbow, and if you want to get a teacher on your good side, ask her or him about why the colors are reversed in the second half of a double rainbow. Let me know what happens.

—Jennifer White


Michael Gottesman
Deputy Director for Intramural Research, OD

John I. Gallin
Director, Warren Grant Magnuson Clinical Center,
and Associate Director for Clinical Research

Lance Liotta
Chief, Laboratory of Pathology, NCI


Celia Hooper

Fran Pollner

Shauna Roberts

Aarthi Ashok
Karen Ross
Jacqueline Ruttimann

Jennifer White



Jorge Carrasquillo, CC
David Davies, NIDDK
Dale Graham, CIT
Hynda Kleinman, NIDCR
Elise Kohn, NCI
Susan Leitman, CC
Bernard Moss, NIAID
Michael Rogawski, NINDS
Joan Schwartz, NINDS
Gisela Storz, NICHD


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