Body & Senses
How do my eyes see?
A red triangle leads Puschel to a discovery about light and sight.
The short answer
Light from an object enters your eye. The cornea and lens direct it onto the retina at the back. Signals are produced there, and your brain processes them into what you see.
Light in, signals onwards
1. Light enters your eye
You see a book when light falls on its pages and some reaches your eyes.
2. Focusing the light
The cornea, the clear front surface, and the lens further inside bend light.
3. The brain processes signals
Retinal sensory cells respond to light and produce signals.
The red line at the back of the eye diagram is the retina. Lines up to it show light paths.
The green arrow afterwards stands for nerve signals to the brain. This is a diagram; a ready-made picture does not travel along the nerve.
An imagined Wusel scene
Puschel and Flauschi investigate
Colourful shapes lie on a mat. Puschel points to the red triangle while Flauschi holds a blue square.
Puschel“My eyes find red faster than my paws do!”
Flauschi“Light from the shapes enters your eyes. Without light, we could not see them.”
Puschel looks at the yellow circle. Puschel“Do the eyes send a message to the head?”
Flauschi“In people, signals are produced at the back of the eye. The brain processes them.” They sort the shapes together. Puschel discovers that colour and shape are two different things to notice.
Little Wusel quiz
What do eyes need for seeing?
Choose one answer: a), b).
- a)Light
- b)Sound waves instead of light
Show answer
Correct answer: a): Light Light needs to enter the eyes.
Which two things can you describe about a red triangle?
Choose one answer: a), b).
- a)Its colour and shape
- b)Only its colour
Show answer
Correct answer: a): Its colour and shape You can describe its red colour and triangular shape.
Word help
- cell
- A tiny living unit. Living things are made of cells.
- nerve
- A bundle of fibres that carry signals through the body.
- retina
- The light-sensitive layer at the back of the eye where signals are produced.
Explore in more detail
Here you will find longer explanations and further details. You can explore them together.
Understand step by step
How it works – simply explained
Light enters your eye
You see a book when light falls on its pages and some reaches your eyes. The pupil is the dark opening at the front, not a black object.
Focusing the light
The cornea, the clear front surface, and the lens further inside bend light. Together they focus it onto the retina, the light-sensitive layer at the back.
The brain processes signals
Retinal sensory cells respond to light and produce signals. The optic nerve carries these to the brain for processing. A tiny finished book does not travel through the nerve; messages do.
How you see a red ball
A lamp or the Sun lights the ball. Light from it enters your eye. The cornea, the clear front surface, and the lens further inside direct light onto the retina. The lens also helps focus it. Sensory cells in the retina respond to light, and the brain processes their messages into what you see as a red ball. In complete darkness, light from the ball is missing.
The key points again
Discovery 1
Our eyes need light entering them in order to see.
Source: [1]
Discovery 2
At the front of the eye is the clear cornea. Behind it sits the lens, another clear part. Together they bend light to focus it on the retina at the back of the eye. The retina is a light-sensitive layer.
Source: [1]
Discovery 3
The retina contains sensory cells. These special cells respond to light and help produce signals. The signals travel along the optic nerve to the brain, where they are processed so we can see.
Source: [1]