Boxi Learn › Computing › Stage 2 · Models and Patterns
A picture is a grid of numbers
CS-3 Any information can become numbers
What many people think
A computer stores a picture as a picture, not as numbers.
The idea
A screen picture is a grid of pixels, and each pixel's colour is three numbers: red, green, blue.
Explain it
A friend says “the computer just saves the photo”. Explain what it really saves, and why a white pixel is (255, 255, 255).
Try at home
Look at a screen through a magnifying glass, or put a drop of water on a phone screen showing white: on many screens you will see tiny red, green and blue lights.