Question: I'm interested in the idea of all computers using 1's and 0's. Can you tell me more about this???

Suzanne McEndoo answered on 11 Mar 2012:

Hi, that’s a good question, and I hope I can answer it ok.

We don’t usually think about it but all information has to be represented physically. When you write an essay you translate your thoughts into symbols called letters and store them physically as marks on a page. Or if you say “Hi” to your friend, you use your voice to make a particular sound vibration which travels through the air, into your friends ears which vibrate and translate that vibration into the message you sent.

You computer plays the same kind of game with information. Music, photos, games, emails, are all information and have to be stored and processed in a way the computer can understand. Physically your computer can only understand two different basic pieces of information, a zero or a one. It sees no current flowing as a zero, and current flowing as a 1. Or light on is 1, light off is zero.

This seems really limiting but it’s very very useful. The easiest thing to store this way is numbers, using a system called Binary (http://en.wikipedia.org/wiki/Binary_numeral_system). Binary works similarly to our usual decimal (10 based) number system. Usually the right most number is ones, then tens, then hundreds, then thousands, etc. So
12345 is
5 ones, 4 tens, 3 hundreds, 2 thousands and 1 ten thousand.

In binary, instead of tens, we have twos. So we start the same way, with ones, then instead of tens it’s twos, and instead of 100s it’s 4s, then 8s then 16s. So the first few numbers in binary are written as
1 (one)
10 (one two, no ones = 2)
11 (one two, one one = 3)
100 (one four, no twos, no ones = 4)
101 (one four, no twos, one one = 5)
110 (6)
111 (7)
1000 (8)

so this way we can translate numbers into a sequence of current flowing or not flowing.

In order to store anything else, it’s just a case of translating it to numbers. So for a picture you can map all the colours to numbers and all the positions to numbers, so position X, colour Y. So your computer can send this series of numbers to your friends computer. Since this is all done using a standard set of instructions, your friends computer can read the numbers and reconstruct the image on your screen.

The same thing happens to things like music, movies and text. You can check out Unicode (a standard way of assigning numbers to parts of text) on wiki here http://en.wikipedia.org/wiki/List_of_Unicode_characters#See_also. There’s all sorts of symbols that I’ve never used and wouldn’t know how to use, but they all have their own number.

That’s a physicist’s explanation of how computers use ones and zeros. If you want to know more, some things to look up are binary, central processing unit (this is the processor in your computer, all it does all day is add and subtract lots of 0s and 1s, it’s incredible!), and boolean logic (the type of logic that uses 0s and 1s and is the basis of computers).