This week the Year 7 Science Club played tricks on their eyes by making Thaumatropes.  Thaumatropes are two images on either side of a card, so that when the card is spun quickly, your eyes see only a single image.  Thaumatropes were invented in the 1820s to show the phenomena of persistence of vision.  When you see an image, it lingers on your retina for about one-tenth of a second. Spinning a thaumatrope quickly, fools your eyes by switching images faster than the tenth-of-a-second limit, this makes the images merge.

The Year 7 pupils either made a carousel horse appear on a merry-go-round, or a butterfly appear in a jar.  Their great use of colour made the images stand out even more to the eyes. 

Have a look at the video below and see if you can observe the effect.