A thaumatrope - a type of optical illusion - makes two images
appear as one.
For example a picture of a cage and a picture of a lion will
turn into a picture of a lion in a cage!
What you need:
- Thaumatrope template - draw your own or download the one in the
video from Questacon -
tricky pictures (pdf).
- Scissors
- Black pen or coloured felt tips
- Skewer (you could use a pencil or a straw instead)
- Sellotape
- Pen
How to:
- Use the thaumatrope template from Questacon -
tricky pictures or draw your own. You can use any pictures that
go together. How about having hair and a smile on one side, and a
nose and eyes on the other side?
- Cut out the template and fold it in half, with the pictures on
the outside.
- Tape the skewer inside the template, with one end of the skewer
against the fold and the other end showing at the bottom, like a
lollipop.
- Tape the template together, with a picture showing on either
side.
- Hold the stick between your hands and twist it slowly. The
template will flip from one picture to the other. Speed up the
twisting. What do you notice?
Try this with other pictures! What else would you like to put in
a cage?
What's happening?
You've made a thaumatrope! When you twist the skewer in your
hands, the two images seem to merge. This is a type of optical
illusion.
When you look at images, your brain remembers them for a
fraction of a second after the image has disappeared. This is
called "persistence of vision".
If you see more than 10 images per second, your brain puts them
together as a series of moving images.
Films use the same trick. In films, there are 24 still images
(frames) per second. Your brain puts all those images together as a
series of moving images.