Seeing Ghosts!

You will need:

2 sheets of white paper
A red felt tip pen

What to do:

Draw a ghost in red on one of the sheets of paper and colour it in.
Stare at it for about 30 seconds… you’ll start to see a green outline around it when your eyes are ready.
Now look at the second, blank sheet of paper.
You should see a ghostly green image hovering on the paper!

What’s going on?

Eyes get tired like any other part of the body. When you look at a red image the cells in your eyes’ retinas respond to the colour, but after a while they get tired and stop functioning as well. White light is made up of all colours, so when you then look at a white sheet of paper not all the red light is picked up by your tired eyes and you are left with an after image of green.

Click here to download some ghost drawings you can colour in & trace.