What is a thaumatrope?
A thaumatrope is a toy that uses the science of optics to trick your eye into seeing two images as one. Thaumatropes are made from a disc with a different picture on each side, these pictures appear to come together as one image when the disc is rotated quickly.
Popular designs include a bird in a cage and a fish in a bowl, but many other and original designs have since been used.
They were invented by English Physicist John Ayrton Paris in 1825 and became massively popular during Victorian times, along with other optical motion toys such as zoetropes and phenakistoscopes. They were popular with people of all classes, but were more popular with poor people than the other optical motion toys, probably because they were easier and cheaper to make than the others. Despite their past popularity, original Victorian thaumatropes are now quite rare, presumably because they have worn out as they were often made from paper or card.
How do they work?
The job of the retina in your eye is to send visual information from your eye to your brain via the optic nerve. Whilst this process can be very efficient it is not instant, an image produced by your retina can linger in your vision for a split second after it is no longer present, this is known as “the principle of the persistence of vision.”
Have you ever stared at a bright image for a while, looked away and then seen it ‘magically’ appear in another place? This is called an afterimage and is just one of the optical illusions that our eyes can make.
Another example of a way that persistence of vision can trick our brains is sparklers. Have you ever used a sparkler to write your name or draw a picture? The trail of light from a sparkler appears because of this delay in our retina processing the image and sending the information to our brains.
Making your own thaumatrope
You will need:
· a sheet of card
· a roll of sticky tape, plastic lid, or another circular shape to trace
· hole punch
· two rubber bands
How to do it:
1. Draw a circle on a piece of card. You can trace something with a circular shape, like a roll of sticky tape or plastic lid.
2. Cut out the circle and punch two holes on opposite sides near to the edge.
3. Draw your first picture on one side. Note: Make sure that the two holes are lined up straight before you start,
4. Now flip the circle over from bottom to top.
5. Draw your second picture on the other side.
6. String a rubber band through one of the holes, and thread one end through the loop at the other end. Repeat on the other side.
7. Pull the rubber bands tight and use your forefingers and thumbs to spin the circle back and forth.
8. Watch your two drawings become one!