ScienceIQ.com

Somewhere Over Which Rainbow?

How many rainbows are there really when we only see one during a rainstorm? The answer isn't as simple as you might think! Rainbows are formed when light enters a water droplet, reflects once inside the droplet, and is reflected back to our eyes. Each raindrop reflects and refracts the light that enters it in all possible ways. When light first ...

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DoubleRainbow
Mathematics

Origins Of The Meter

The origins of the meter go back to at least the 18th century. At that time, there were two competing approaches to the definition of a standard unit of length. Some suggested defining the meter as ... Continue reading

OriginsOfTheMeter
Astronomy

Large Asteroid Zooms Safely Past Earth

A mountain-sized asteroid made its closest approach to Earth at 9:35 a.m. Eastern Time on Wednesday, Sept. 29, 2004. Although asteroid 4179 Toutatis came no closer than four times the distance between ... Continue reading

LargeAsteroidZoomsPastEarth
Geology

Surprise! Lightning Has Big Effect On Atmospheric Chemistry

Scientists were surprised to learn summer lightning over the U.S. significantly increases regional ozone and other gases that affect air chemistry 3 to 8 miles above Earth's surface.The amounts of ... Continue reading

AtmosphericChemistry
Biology

What's The Difference Between A Sweet Potato And A Yam?

What's in a name? Although supermarkets offer both 'yams' and 'sweet potatoes,' in fact they are all sweet potatoes. True yams are rarely seen in the United States, and are actually quite different ... Continue reading

SweetPotatoYam

Marmaduke and the Taco Bell Chihuahua Are Cousins

MarmadukeYou would never think Marmaduke, the enormous great dane of the newspaper cartoons, and the tiny Taco Bell chihuahua are close relatives. But the fact is, ALL dogs are pretty close relatives. Scientists now believe that all dogs, including the semi-wild dingoes of Australia, Arctic huskies, Shetland sheepdogs, great danes and tiny chihuahuas, are descended from only two original domestic dogs. DNA evidence also suggests that dogs are all derived from wolves, not coyotes or jackals.

The DNA evidence further suggests that dogs were first domesticated about 100,000 years ago. However, the first dog fossils, found in Europe and Asia, date from only 14,000 years ago. The scientists who did the DNA study think that early dogs looked so much like wolves that they can't be distinguished from them in the fossil record until about 14,000 years ago. People later took their dogs with them as they spread out over the globe, to Australia, the New World, and the Pacific Islands. Wild dogs recently discovered in the southeastern United States may be descended from the dogs kept by the Native Americans.

Domestic dogs are smaller than their wild forebears, with smaller brains, less acute senses, and smaller teeth. In appearance and behavior, they are immature, puppy-like wolves.