Binary Switches, Bits, Bytes, Nibbles, and Words
Computers are ultimately composed of switches which are either on or off. Therefore, it is practical for computers to use binary digits (bits) to represent information. Bits can represent just 2 possible values- 0 or 1. This corresponds nicely with switches.
Bits are grouped into words which represent larger ranges of values. A 4 bit word is a nibble and represents 16 values. An 8 bit word is a byte (or, more precisely, an octet) and represents 256 values.
Modern computers typically use 32 bit (over 4 billion values) or 64 bit (over 18 quintillion) words.
Below are 4 switches which represent a nibble. You can toggle each switch below by clicking on them and the word's value on the right will update accordingly. The upper number is written in decimal and the lower is in binary format.