What is binary?
  1. What is binary?
  2. Why do computers use binary
  3. How does it work?

Can you guess what the item is?

Item 1 – Circa 221 BC



Smoke signals

These are smoke signals being sent along the great wall of china. The signals were used to warn of enemy attack and could send messages at a speed of over 100km per hour.

Item 2 – Circa 1726 AD




Punch Card

This is a card card, originally used in the 19th century to control textile looms in factories.

Item 3 – Circa 1965




Fibre Optic cable

This is a fibre-optic cable, used to transmit data at very high speeds.

Item 4 – Circa 1988





This is a microscopic view of a CD ROM surface!

Item 4 – Circa 2014


Quantum Communication

This is Quantum communication.It relies on Quantum mechanics and is the most secure and fastest of all technologies to date.

Extension – What have all these technologies got in common?



All these technologies communicate using binary!

Key Definition – Binary

ic_action_edit Binary is the number system that computers use to store and transmit information. It is based on the Boolean values 0 and 1 (False and True).

All information that is stored and transmitted in computer systems is done so using binary.



Why do computers use binary?

Computers use binary because it is the most reliable method of storing and transmitting information.

Computers send data using electricity and electrical signals are rarely stable enough to guarantee a fixed value.

Example Voltage within a Micro-controller


If you look at the graph above, you will see that the voltage doesn’t stay steady enough to transmit the data accurately.

The only safe way to check for two possible voltages – ON( + /- V ) and Off (0v) .

Therefore we would need to use binary!


Binary information is now commonly stored using one of three types of storage media:1

  • Optical Media
    • CDs
    • DVDs
    • BluRay
  • Magnetic Media
    • Hard Disks
    • Floppy disks
    • Tape Drives
  • Solid State Media
    • SD Cards
    • Solid State Drives

Binary information is usually transmitted by using:

  • Copper Wires using electricity
    • Telephone Wires
    • Ethernet Cables
  • Fibre Optic Cables using light
    • High Speed Broadband
    • Undersea Cables
  • Wirelessly using radio / microwave signals
    • Home Wifi
    • Mobile Phones
    • DAB Radio

How many different binary codes can you find in this binary song on YouTube?