Binary is a number system that only uses two digits: 0 and 1.
In everyday life, we use the denary (Base-10) system, which means we can represent ten numbers: 0 – 9.
We use Base-10 because we have ten fingers to count on!
Computers use the binary (Base-2) system, which can only represent two numbers: 0 – 1.
Computers do not have fingers, but they have switches which can be either off (0) or on (1).
Everything is Binary
Everything a computer does is stored and processed as binary numbers. For example:
Pressing Keys
Each key your press is represented as a binary number
Images
Each pixel in a photo or video is a binary number
Audio
All your music and sounds are stored as binary numbers
Processing Data
The CPU (central processing unit) can be thought of as the computer's brain.
Inside the CPU are billions of microscopic transistors, which act as switches. Each switch can be on (1) or off (0).
Switches are toggled on and off really quickly. There are complex pathways between the switches. Combining the switches and pathways allows the CPU can do all of the amazing things we depend on them for.
Storing Binary
Random Access Memory (RAM)
Data which the computer is currently using is stored as positive and negative electrical charges. These charges represent 1s and 0s.
Magnetic Storage
Data which the computer stores long-term on a hard disk drive is stored as positive and negative magnetic charges. These charges represent 1s and 0s.
Optical Storage
CDs, DVDs, and Blu-Ray discs have millions of tiny holes in the metal layer.
The laser detects differences between the surface and the holes, and these are interpreted as binary data (0s and 1s).
Solid State Storage
Data is stored in solid-state and flash media using tiny electronic cells that trap or release electrical charge to represent binary values (0s and 1s).
When data is read, the device checks the charge in each cell to determine whether it represents a 0 or a 1.