Thursday, 9 February, 2012

The saltiness of the sea comes from dissolved minerals, especially sodium, chlorine, sulfur, calcium, magnesium, and potassium, says Galen McKinley, a UW-Madison professor of atmospheric and oceanic sciences. Today’s ocean salt has ancient origins. As the earth formed, gases spewing from its interior released salt ions that reached the ocean via rainfall or land runoff. [...]

Scott Bachmeier, a research meteorologist at the Cooperative Institute for Meteorological Satellite Studies at UW-Madison, says that particles in the air scatter light. In the day, the particles scatter more violet and blue light, but our eyes are more sensitive to blue light — that’s why the sky appears blue. Thunderstorms, which can be the [...]

Clouds are made of uncountable tiny particles, either water droplets or ice crystals, or a mixture of the two, says Grant Petty, a professor of atmospheric and oceanic sciences at the University of Wisconsin-Madison. “The water droplets are usually about 10-20 micrometers across, or about one-twentieth of the diameter of the period at the end [...]

The luscious aroma of flowers attracts lovers, and the biological role of that smell is similar: to attract pollinators. “Plants need to attract insects, bats and hummingbirds to transfer the pollen and create fertile seeds,” says Hugh Iltis, professor emeritus of botany at UW-Madison. Pollination is the transfer of pollen (the plant equivalent of sperm) [...]

A lot better than we do, says Paul Miller, clinical professor of comparative ophthalmology at University of Wisconsin-Madison. “Dogs have evolved to see well in both bright and dim light, whereas humans do best in bright light. No one is quite sure how much better a dog sees in dim light, but I would suspect [...]

“Technically, there is no surface of the Sun,” says UW-Madison’s Sanjay Limaye. The senior scientist and educator with the Space Science and Engineering Center explains that unlike the hard, physical boundary here on Earth, the Sun’s surface is a hot mass of gas that is more or less continuous with its atmosphere. “The Sun is [...]

After a strong rain, the corpses of worms strewn across the pavement are a disgusting sight – or a pathetic one, depending on your sympathy for these slithery invertebrates. But what’s the advantage of suicide? Teri Balser, an associate professor of soil and ecosystem ecology at UW-Madison, says the answer starts with the fact that [...]

Fingernails are essentially flattened versions of claws, and they evolved in all primates — including humans — to support broad fingertips, says UW-Madison anthropology professor John Hawks. Monkeys, apes and lemurs spend a lot of time in trees, and broad fingertips help give them the strong grip needed to climb trunks and hang underneath branches. [...]

“The answer is rooted in the fact that our planet is a ‘living’ planet, which is still cooling,” says Laurel Goodwin, professor of geology at UW-Madison. She describes Earth as a series of shells, like a peanut M&M. “The candy shell is the crust, on which we live. The chocolate beneath is the mantle, and [...]

Built for crunching and chewing, teeth mostly consist of hard, inorganic minerals like calcium. But they also contain nerves, blood vessels and specialized cells that manufacture the tooth’s different parts, says Bill Gengler, a veterinary dentist and oral surgeon with the UW-Madison School of Veterinary Medicine. The tooth’s outermost layer – the part we brush [...]