The Persistence of Vision

Animation derives off of motion, ironically however motion is just a succession of still images with no motion at all. This optical illusion is the roots to how animation is created.

TED-Ed has a brilliant video called "The optical illusion of motion" which observes different still frames of a character and begins to play them in quick succession one after another, creating a "single, persistent image that's gradually changing form and position." This is what is known as "The Persistence of Vision".

https://www.youtube.com/watch?v=V8A4qudmsX0

We see this effect all around us, like arcade machines for example where light bulbs light up one after another creating a movement around the machine, although they're only lighting up it creates the illusion of a moving object.

Back to the TED-Ed video, they go through different frame speeds to see what fps is the lowest for people to identify the set of moving images as an animation, this was something I actually never knew. I was aware that 24 fps was the standard speed animations normally go for, however it seems that even at around 10 fps your eyes may struggle to detect still images and begin to see an animation being formed.