FIONÙIR, HOW DO WE SEE LIGHT

HOW DO WE SEE LIGHT

Have you ever thought about how we can see light? Or if animals can see the same way as we do?

Well, light is made up of tiny, tiny bits. When the Sun shines, trillions and trillions (1,000,000,000,000) of these light bits fall onto the Earth. These tiny bits or cells are called photons.

Photons

These photons bounce off almost everything and some of them enter our eyes and allow us to see!

Special cells in our eyes tell us what kind of light it is with the help of our brainy brains. These cells are called photoreceptors. They are found at the back of the eye in a layer called the retina. Please see my drawing of the eye. This word is easy to remember. Just think about elderly people in Germany who don’t work anymore, “Rentner”! Let’s connect the dots!!

Picture of the eye

Yellow part is the retina (cones and rods).

How do our photoreceptors work?

There are two types of photoreceptors.

They are cones and rods which are found in the retina. They have these names because of their shapes. They are easy to remember!! Just think about ice-cream cones and fishing rods!!

Diagram of a rod (black and white) and cone (colours)

 

A cone of yummy ice-cream and cones in your eyes!

A fishing boat and a fishing ROD. In the early morning in the DARK light.

There are three types of cones. And each one lets us see the main colours, red, blue and green.

Just think about lots of different ice-creams; strawberry (red), blueberry (blue), gooseberry (green)!). Cones are more sensitive than rods therefore we can’t see so well at night.

Rods let us see black and white. Just think about out on a fishing boat in the early morning with all the dark colours around.

You may have heard of colour blindness? What is colour blindness? Well, it is a genetic defect. Colour blindness affects 9% of people. Actually men have it more than women!!

Colour blindness

Some animals can see better than others. Some have more photoreceptors than others. You can see this by the animal that they kill. For example, if an animal kills another animal for food and that animal of prey is brightly coloured then the animal that kills can see lots of colours.

Interesting, isn’t it!!

Animal with its animal of prey

Hope you enjoyed reading up on how we can see.

Cheers for now …

Fionúir