Background reading · Technology
Zeros and ones: how computers store everything
How binary works, why computers use it, and how your score, your sprites and your sounds all become zeros and ones.
Inside every computer are billions of tiny switches. Each switch can only be on or off. We write on as 1 and off as 0. Every photo, song, message and game on your device is stored as a long pattern of these zeros and ones. This is called binary.
Counting with only two digits
We usually count in tens: ones, tens, hundreds. Binary counts in twos. Each place is worth double the place to its right: 1, 2, 4, 8, 16, 32 and so on. To write 13 in binary, find which places add up to 13: 8 + 4 + 1. So 13 is 1101 (one 8, one 4, no 2, one 1).
Bits and bytes
Letters and pictures
Computers store letters by giving each one a number, then storing the number in binary. Pictures are made of tiny squares called pixels. Each pixel's colour is stored as numbers for how much red, green and blue it has. Your Scratch sprite is a grid of pixels, and every one of them is stored as binary.
Why only two?
It is much easier to build a switch that is reliably on or off than one with ten different levels. Two states are fast, cheap and hard to confuse, even with a little electrical noise. That is why binary has been used in computers for more than 80 years.
Binary in your game
When your Scratch score reaches 7, the computer stores it as 111. When it reaches 8, it becomes 1000. Try the binary cards and see if you can read your final score in binary.
Sources and further reading
Written for Kōkiri Learn students in our own words. Check facts against the sources.