Where: All across the United States.
When: March 5th, 2008.
What: Scientists have found a way to figure out where a person is from and where he or she has been, just by looking at samples of the person's hair.
I like this discovery because it seems useful. Since more than half our body weight is water, our bodies start breaking the water down into its parts: hydrogen and oxygen. The atoms of the hydrogen and oxygen end up in our tissues, fingernails, and hair. But naturally, not all water is similar. The atoms differ in how they weigh. Different forms of a single element are called isotopes. But based on where you reside, the tap water holds different amounts of the isotopes of hydrogen and oxygen. James R. Ehleringer and his colleagues found out by collected hair from barbers and hair stylists in 65 cities in 18 states across the United States, assuming that the hair collected came from people who lived in the area. Although people drink a lot of bottled water now, the scientists discovered that the hair reflected the concentrations of hydrogen and oxygen isotopes in local tap water. Maybe because many people cook food using the local tap water. The scientists combined that information with their results to predict the composition of hair in people from different regions. This new technique can't point to exactly where a person is from, but now authorites can use it to analyze hair samples from criminals or crime victims and narrow their search for clues.
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