In the real world, the basic laws of physics were first described by Sir Isaac Newton and Albert Einstein. In the world of animation, however, we owe the laws of physics to Frank Thomas and Ollie Johnston. Working for the Walt Disney Company in its heyday of the 1930s, these two animators came up with the 12 basic principles of animation, each of which can be used to produce the illusion of characters moving realistically in a cartoon.
Note: The goal of animation is not realism, but the illusion of realism. For example, in rotoscoping, you film an actor and then laboriously trace over the images to convert his or her movements into a living cartoon. But unless you constantly tweak what you're tracing for the medium of animation, the results look creepy. The lesson? The goal is not to make objects move as realistically as possible, but rather to make them move as fluidly as possible, regardless of realism. Good animation requires entirely different laws of physics.
Which is why the 12 Basic Principles of Animation are so important. Thomas' and Johnston's 12 principles have now been turned into a wonderful animated primer, thanks to motion artist Cento Lodigiani. Using just a cartoon cube, Lodigiani makes the 12 principles of animation--from squash and stretch to secondary action--immediately understandable, regardless of your training.
"The 12 basic principles of animation were developed by the 'old men' of Walt Disney Studios," Lodigiani writes. "These principles came as a result of reflection about their practice and through Disney's desire to use animation to express character and personality. This movie is my personal take on those principles, applied to simple shapes. Like a cube."
What's great about Lodigiani's movie (and the animated GIFs made from them) is how easy it is to see the movements of your favorite Disney cartoon characters. That cartoon box isn't just a cube; it's Donald Duck throwing a temper tantrum, Ariel launching herself out of the sea, Mickey Mouse doing a double take, and even Goofy getting himself tangled up in a pair of skis and plummeting off of a cliff. Yaaah-hoo-hoo-hooey!