Norman McLaren, a pioneer of 20th century animation, once said that "what happens between each frame is more important than what exists on each frame." But what the hell did he mean?

This video, by TED Ed, explains how tiny differences in timing and spacing—qualities provided by differences between frames rather than the frames themselves—can turn a an awful mess of an animation into something wonderful. The differences are subtle, barely perceptible frame-to-frame, but add up to have a huge impact—and it's all demonstrated very neatly with an example of a bouncing ball. Well worth watching. [TED Ed]