Thread the Needle

A red and blue exhibit table, with an orange, purple and white information panel at the back, sits in front of a green and a blue wall. On the table is a white vertical post with a slot in the top, that has a black rectangle inserted into the slot.

How it works

Attempt to thread a larger-than-life needle at arm’s length and with one eye closed.

Things to try or ask around the exhibit

Can you ‘thread the needle’ with one eye closed?

Background

When you look at something with two eyes, each eye sees the object from a slightly different angle. Your brain uses the difference between your right and left eyes to work out how far away the object is positioned. This is stereo or binocular vision.

Finding the science in your world

Humans can accurately judge the distance of objects up to 20 metres away using stereo vision. Some people who suffer an eye injury lose their stereovision, but they are able to compensate for this loss and judge the distance of objects relatively accurately.