Power of explanation

I was speaking to a scientist yesterday who explained he can measure certain chemical reactions with a femtosecond delay, which is getting pretty close to real time. “What’s a femtosecond?” someone asked. Most scientists would have answered 10^-15 seconds. Instead, this eloquent scientist said, “One second is the time it takes for light to travel from the moon to the earth. A femtosecond is the time it takes for light to travel the width of a human hair.”