How Fast Is Fast?—Harold "Doc" Edgerton
NARRATOR: Introducing Dr. Harold E. Edgerton of the Massachusetts Institute of Technology. His stroboscope light my friends is really something.
NARRATOR: Through this invention you can examine machinery in motion. When you direct this light on a fan, and synchronize the light flashes to the revolutions of the fan, the blades appear to be stationary. Effects evident only while a machine is in motion, and thus easily discovered.
While normally film runs through the average movie camera at 90 feet a minute, Edgerton's flicker box can handle 125 feet a second. Connected with it, is the unit containing the thyratron amplifier, and boy, am I getting over my head. Anyway, flashing on and off, up to 2000 times a second, this light makes 2000 exposures a second on the film in the camera, as it speeds past the lens.
And so it is now possible to get ultra slow motion pictures. In normal speed movies, a bullet shot from the muzzle of a high powered air gun is invisible. Now Edgerton really photographs a bullet in flight. Watch it come in from the left. And when you recall that all of the action of this bulb smashing actually took place in the fraction of a second, you realize that here is speed in movie photography indeed.