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Opinion, arguments & analyses from guest experts and from the editors of Scientific American

With a little help, water can freeze as it heats up

The Celsius scale is an elegant, simple system of measurement: water freezes at 0 degree Celsius and boils at 100 degrees C. (The actual definition of the scale is a bit more complex, involving the so-called triple point of water, but that's the general idea.) But chefs at high altitudes know that the simplicity of Celsius doesn't always hold—the higher your kitchen, the lower the boiling point of water.

February 4, 2010 — John Matson

Sperm cells' swimming secrets revealed

The predictable swimming sperm featured in health class videos are rather uncharacteristic portraits of the life of these sex cells.

Spermatozoa actually spend most of their time resting up in the male reproductive tract so they can make a dash to the egg once the opportunity arises.

February 4, 2010 — Katherine Harmon

Scientific American launches "World Changing Ideas" video contest

Got an idea for a better tomorrow? Enter it into our video contest. Continuing the theme of Scientific American 's December 2009 cover story, “World Changing Ideas,” which highlighted the power of science and technology to improve the world around us, we are encouraging readers to submit video entries about innovative ways to build cleaner, healthier, smarter ways of life.

February 1, 2010 — Philip Yam

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Know Before You Vote

Know Before You Vote