In China, scientists recently discovered what may be the oldest playable musical instrument in the world. To determine its age, they had to examine one unique carbon atom among billions. I’m Jim Metzner, and this is the Pulse of the Planet, presented by DuPont. We’re listening to the sound of a traditional Chinese folk song being played on a nine thousand-year-old flute. How do we know it’s that old? Well, through a process called carbon dating. Garman Harbottle is a senior scientist emeritus at the Brookhaven National Laboratory in Upton, New York. He’s worked with the University of Science and Technology of China to help determine the age of this ancient flute.

“The purpose of a carbon dating experiment is to measure the number of carbon 14 atoms in a carbon sample compared to the total. Now only one in about a hundred billion atoms is a carbon 14. So this is a little bit like a needle in a haystack. But we have machines that will separate out that one from a hundred billion ordinary atoms.”

Carbon 14 is a particular kind of carbon atom, and it decays at a predictable rate over time. Once scientists have located the carbon 14 atoms in an artifact they’re trying to date, they’ll compare them with the carbon 14 atoms in another object whose age is already known.

“For example, we have tree rings. You know, your big old redwoods where we can simply count the number of tree rings back for thousands of years and thus obtain samples of wood and that means samples of carbon that date back to that time. So we know how many there were there at that time and that’s a so-called calibration.”

So with the help of carbon dating, scientists tell us that these sounds are like an echo from another era – nine thousand years ago.

Pulse of the Planet is presented by DuPont, bringing you the miracles of science, with additional support provided by the National Science Foundation.