Uncategorized
- Materials Science
Fridge Magnets and Chemistry
Theres a tiger on your fridge! Lurking inside refrigerator magnets of the flat, flexible variety are magnetic-field stripes of alternating polarity. This University of Wisconsin Web site explains how fridge magnets work, shows how you can use such magnets to learn about magnetic force microscopy, and suggests experiments involving fridge magnets to model how metals […]
- Math
Whips and Dinosaur Tails
The loud crack of a deftly flicked bullwhip can certainly command attention. That distinctive noise is a small sonic boom, generated when the whip’s thin, highly flexible tip exceeds the speed of sound. Swinging a leather bullwhip’s thick, rigid handle in an arc gives the whip angular momentum. Sharply reversing the motion’s direction sends a […]
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19117
This article fails to make the distinction between the synthetic hormone progestin and the naturally occurring hormone progesterone. Progestin is medroxyprogesterone acetate (MPA), which is manufactured from the urine of pregnant mares. MPA is 10 to 100 times more potent in its effects on women than natural progesterone and does not produce the same reactions […]
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19121
As many wives of depressed men will tell you, depressed husbands don’t just mope around. They are often angry, upset, unpredictable, and short-tempered. Kind words are often followed by angry words and periods of self-pity. The wife lives in a minefield and often finds it difficult to believe or accept positive comments. There is very […]
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19120
I read with interest your article on determining the origin of emeralds by measuring oxygen isotopes. While there is great potential for legal and historical applications, I think that using this method to determine the source of gems for purely economic reasons is ludicrous. At least for myself, whether an emerald originated in Austria or […]
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Corn Defenses: Bitten plants deploy gut-rotting enzyme
Some corn varieties that arose on the Caribbean island of Antigua defend themselves with chemical attacks that leave insect gut linings in tatters.
- Health & Medicine
Smoking Gun? Mouse tests link nicotine to crib death
Nicotine may impair a molecule that's necessary for arousing people and other animals from sleep, an effect that could account for the heightened risk of sudden infant death syndrome in babies born to women who smoked during pregnancy.
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19116
There are unfortunate multiple misuses of the word “artificial” in describing lab-grown diamonds in this article. In gemological use, artificial means imitation or not real. In fact, the lab-grown diamonds described in your article are real, synthetic diamonds with all the properties and chemistry of natural diamonds. Fred WardBethesda, Md.
- Materials Science
Better-Built Diamonds: Fast growth, purity may multiply uses
A research group has fabricated the purest diamonds ever made or found, and another has devised a way to grow high-quality diamonds up to 100 times faster than typical growth rates.
- Math
Doing the Wave
It was the first home game of the season for the University of Maryland football team. About 48,000 fans had crowded into Byrd Stadium to watch the Terrapins take on the University of Akron Zips. Inevitably, during a lull in what turned out to be a rather one-sided contest, the assembled spectators created their own […]
- Humans
From the March 8, 1930, issue
LEAVES OLDER THAN GRAND CANYON FOUND Fossil remains of plants found in the walls of the Grand Canyon show that many millions of years ago stunted vegetation of very singular aspect grew in a great, red, sandy floodplain under a semi-arid climate in northern Arizona. This great red land has been found by Dr. David […]
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Making Waves
Dive into ocean waves, tides, currents, and much more at the Office of Naval Researchs oceanography Web site. This educational resource for students and teachers provides information on topics such as the creatures inhabiting hydrothermal vents, suggests simple experiments focusing on the forces that keep ships afloat and allow submarines to sink, and offers quick […]
