Number 17: The Stopped Clock Illusion

Our brains are really astonishing things. There's a whole lot of stuff that we think we see, but really our brains are just making stuff up to fill in the gaps in our perception. But sometimes we can catch out brains out and see through the illusions they create for us. One example is with the blind spot on the backs of our eyes that I described it a while ago. Here's another example called 'the stopped clock illusion'. Maybe you've noticed before when you first look at a clock.

You'll need:
A clock with a second hand.

What to do:
Its really simple. Just look at the second hand on the clock. Look away, then quickly look back.

The hand appears to stop for longer than a second. Then it ticks on around the clock face!  Weird isn't it?

What's going on?
The technical name for this illusion is chronostatis (from the Greek chronos meaning 'time' and stasis meaning 'standing').

Scientist aren't completely sure what causes chronostatis. One theory is that our brains can't process information from our eyes whilst they are moving rapidly. So our brain 'backfills time' with whatever the eyes see after they've stopped moving.

If you want to know more here's a (reasonably) easy article to follow.