Colour cells: an animal vision lesson

Pupils connect the number of colour cell types (cone types) in the retina to the colours an animal can tell apart.

Ages 11 to 14 (US middle school; England key stage 3)40 minutesFree animals only

Hook

Ask: what does a camera sensor have in common with the back of your eye?

Steps

1. 5 minShow the photo as you see it, then through the dog, the bee, the pigeon and the mantis shrimp.
2. 10 minOpen the science pages. Pupils record how many colour cell types each animal has.
3. 10 minPupils put the five animals in order and predict how each would see a rainbow.
4. 10 minDiscuss: does the animal with the most colour cell types see the most colours? What else could matter?
5. 5 minLink to light: different colours are different frequencies of light, and each cell type answers to a band of them.

The animals

• You
• Dog
• Western honey bee
• Rock pigeon
• Peacock mantis shrimp

Open the free tool Class mode

The numbers behind them: Dog, Western honey bee, Rock pigeon, Peacock mantis shrimp.

Talk about it

Does having more colour cell types always mean telling more colours apart? What else might matter?

A good answer

Not always: the brain has to compare the signals from the cells, and how it compares them matters too.

Worksheet

Print the worksheet (A4 or US Letter, with an answer key on its own page).

Curriculum links

• NGSS MS-LS1-8: Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior or storage as memories. Source
• England, Key stage 3 physics: Light waves: The human eye; photosensitive material in the retina and in cameras; colours and the different frequencies of light. Source

Curriculum links checked on 2026-10-01 for the US (NGSS) and England only.

All six lessons · Classroom licences