Knowledge empowers people with our most powerful tool: the ability to think and decide. There is no power for change greater than a child discovering what he or she cares about. (Speech about Global Warming read on the National Mall for the 40th anniversary of Earth Day, 2010)

I'm more interested in arousing enthusiasm in kids than in teaching the facts. The facts may change, but that enthusiasm for exploring the world will remain with them the rest of their lives.