Science is Magic

36

DISAPPEARING DOTS

LENS

RETINA

LIGHT

OPTIC

NERVE

P H OTO R E C E P TO R

CELLS

SCIENCE

PART...

THE

This is all about your blind spot,

a point in your eye where you

literally cannot see.

When light enters your eyes, it hits a thin

layer at the back called the retina. This

contains special cells called photoreceptors

that convert the light into electrical signals.

These are sent to your brain, where they are

processed into images. The electric signals

travel along tiny, wire-like nerves that come together

in a bundle called the optic nerve. Since there is no

space for photoreceptors at the head of this nerve,

you’re blind in that spot. Our clever brains fill in

the gap at this point based on what it sees around

it, which in the case of our tricks are the white

and green backgrounds.

Close your right eye. Hold

this image of a dot and an x

about 12 in (30 cm) from your

face. Look at the x. You will

also see the dot in the corner

of your vision.

1

Slowly move

the page closer

to your face. The

dot will suddenly

disappear.

2

BLIND

SPOT

WHERE HAS TH

E DOT GONE?!

US_036-037_Disappearing_dots.indd 36 14/09/2018 09:14