You Asked ...We answered! Experts reveal the shocking truth behind the mysteries of science. How do one-way mirrors one-way mirror n. A mirror that is reflective on one side and transparent on the other, often used in surveillance. Also called two-way mirror. work? Alice Liu, II Armonk, NY There's no magic to one-way mirrors. "Lighting determines how they work," says Ivan Kaminow, senior science adviser of the Optical Society of America The Optical Society of America (OSA) is a scientific society dedicated to advancing the study of light—optics and photonics—in theory and application, by means of worldwide research, scientific publishing, conferences and exhibitions, partnership with industry, and the . Like regular mirrors, a one-way mirror is a piece of glass with a solution of silver nitrate silver nitrate (nī`trāt), chemical compound, AgNO3, a colorless crystalline material that is very soluble in water. The most important compound of silver, it is used in the preparation of silver salts for photography, in chemical (a combination of silver, nitrogen, and oxygen) applied to the back. But here's the difference: a regular mirror contains a "backing" painted over the dried coating of silver nitrate, which prevents light from penetrating through the glass. One-way mirrors contain 50 to 75 percent less silver nitrate. And instead of a painted backing, clear varnish varnish, homogeneous solution of gum or of natural or synthetic resins in oil (oil varnish) or in a volatile solvent (spirit varnish), which dries on exposure to air, forming a thin, hard, usually glossy film. is added. With a weaker reflecting surface and no light-blocking material, only a fraction of light bounces back from the mirror, while the rest penetrates through the glass. So the glass acts like a mirror--but it's see-through at the same time. You don't notice spies spies n. Plural of spy. v. Third person singular present tense of spy. behind the mirror because they're hiding in the dark. If you're standing in a brightly-lit room and no light penetrates from behind the mirror, all you see is your reflection. The spies, however, can see you, but they can't see themselves! What are butterfly wings made of and why does the color come off when you touch them? Jessica Seymore, 12 Oviedo, FL Unfortunately, butterflies don't wear HANDLE WITH CARE labels. Mishandling butterflies may actually kill them! "The extremely delicate wings are made of a thin layer of a substance called chitin (KITE-in) and a system of veins," says entomologist (bug expert) Paul Opler, with the U.S. Geological Survey The term geological survey can be used to describe both the conduct of a survey for geological purposes and an institution holding geological information. A geological survey . On the wings are colorful overlapping rows of tiny scales, "like the shingles shingles: see herpes zoster. shingles or herpes zoster Acute viral skin and nerve infection. Groups of small blisters appear along certain nerve segments, most often on the back, sometimes after a dull ache at the site; pain becomes on a roof of a house," Opler says. But you can rub off the colorful scales very easily because they're attached to the wing merely by a tiny stem. Once the scales are rubbed off, they don't grow back. Butterflies can live without a few scales. "But if you break off a part of the wing, particularly the front part with the strong vein, the butterfly will most likely die," Opler says. Check out Paul Opler's Web site: www.mesc.usgs.gov/butterfly/butterfly.html |
|
||||||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion