Ahmed H. Zewail

Chemist Ahmed Zewail’s biggest contribution to science was his pioneering work on femtochemistry, detecting transitional states during chemical reactions that happen fast enough to be measured by femtoseconds, which is a unit of measurement that represents one-millionth of one-billionth of a second. He was awarded the 1999 Nobel Prize in Chemistry. In 2009 he was appointed to President Obama’s Council of Advisors on Science and Technology and later named an envoy in the new U.S. Science Envoy Program, visiting Muslim countries around the world. Updated 2014