Journeys: Eyes. Stop 4

Cones

Your eye has cells called cones. Some see red, some see green, and some see blue. Tap them!

Together, the three kinds of cones make up all the colours you see.

At night there's too little light for the cones, and the rods take over. They see in the dark but without colours, so at night everything is grey.

Now touch the moon, and night will fall.