Binary: How Computers Store Data
Everything inside a computer is really just 1s and 0s
- say what a bit and a byte are,
- count in binary using 1s and 0s,
- explain how letters and numbers are stored as binary.
1. Everything is on or off
Inside a computer there are millions of tiny switches. Each switch can only be in one of two positions: on or off. There is no "maybe" and no "half". A switch is either on or it is off.
To write this down, we use just two digits:
- 1 means the switch is on.
- 0 means the switch is off.
Because there are only two choices, we call this binary. "Bi" means two, like a bicycle has two wheels. Every photo, message, and game you have ever seen was stored as a long line of 1s and 0s.
2. Bits and bytes
A single 1 or 0 is called a bit. It is the smallest piece of information a computer can hold. But one bit on its own cannot say very much, so computers group bits together.
When we put 8 bits together, we call it a byte. A byte is like a small box that can hold one letter, like the letter "A".
| Name | What it is | Example |
|---|---|---|
| Bit | one 1 or one 0 | 1 |
| Byte | 8 bits together | 01000001 |
| Kilobyte | about 1000 bytes | a short story |
| Megabyte | about a million bytes | a song |
The files on a computer are measured in bytes. A tiny text uses only a few bytes. A photo uses millions of them!