How Computers Work Simplified

So let's say you want to communicate with someone, but you can't talk. You can't use signs. You can't gesture. But you have lightbulbs. You can use them to represent information.

If you're asked a yes or no question like "Are you a man?" you can switch the bulb on for yes, or leave it off for no.

But we have a problem. I said we can't talk. So how do you ask the yes or no questions?

You decide to also represent words using lightbulbs. You start with one bulb. Off is A. On is B. That's it. Two letters. You've run out. You need more.

So you add a second bulb. Now you have combinations. Off-off is A. Off-on is B. On-off is C. On-on is D. Four letters. Still not enough for the whole alphabet.

You add a third bulb. Now with all three bulbs, you can represent A to H. Eight letters.

And then it clicks. You notice the pattern: 2ⁿ. One bulb gives you 2 letters. Two bulbs give you 4. Three give you 8. So you work out how many bulbs you need for all 26 letters. You get your bulbs. Now you can spell anything.

Now we can ask questions using bulbs, and answer using just one because we only need yes or no. That's similar to how computers work, and why we say they use 0 and 1.

You might ask: why do it that way?

Well, we don't necessarily need to do it that way. But think about it. Words are arbitrary values. The word "cat" could be changed to "dog" tomorrow and that's fine, we can't represent words physically. But if you change the number 1 to another symbol and call it something else, it still represents a quantity: a single unit. It doesn't change, unlike words. And it can be represented physically.

That's why we use numbers. And we use binary out of all number systems because it only needs two symbols. Two states are easy to build: on and off, high voltage and low voltage, 1 and 0. The fewer symbols, the simpler the hardware.

So using this, we just need a way to represent the two values of a binary system. A bulb on and off can be the numbers 1 and 0. Even a tap running can represent it—if it's on, it's 1; off, it's 0. That's why it might also be possible to build a computer using water.

But representing it with electric signals is the best. It's fast and efficient.

So then we have these numbers. We've represented words. We can ask questions. Now we want to represent numbers and do calculations on them. Because maths is the foundation of everything. Think about it. If you go to the bank, all they do is subtract when you withdraw, add when you deposit. Same with almost everything humans do. It's almost all maths.

So if we can have our machine represent numbers and perform operations on them, we might have something that does maths faster than the cashier could blink.

Part 2 coming.