Explain the functioning of a computer to a child

A computer is a man-made marvel, as awe-inspiring as any of the seven natural wonders of the world. As God made man, so did Man made the computer. Imagine if I were to ask an ordinary individual to calculate 1+2+3+…+1000 on a calculator; one would consume a lot of time doing the calculation - with a high probability of committing a mistake, whereas a computer can do so with just a few simple commands, and it would carry out the calculations in a fraction of a second (without ever making a mistake)! Insane? I bet, but it’s a small wonder that a computer can do just that, and a lot more, which is saying something, because a modern everyday PC is a compact being, unimpressive and slight, at odds with the large earlier creations. Just as Jane Taylor talks of the mystery behind the beauty of the stars in her poem, “The Star”, when it says “how I wonder what you are”, likewise do computer scientists try to understand and implement the workings of a computer; they are admirers of the computer system.
So, what is a computer? The word computer comes from the word “compute”, which means “to calculate”. For example, if the speed of a computer is 1 GHz, it means that it can process thousand million instructions per second. God blessed humans with some of His attributes, and so did Man in His design of the computer. A computer’s “brain” is the CPU (Central Processing Unit), which converts the input into output. Without the CPU, the computer is just a fancy gadget, unable to perform the many functions it has been designed for.
What needs to be highlighted is the fact that a computer can’t think for itself! It has been “programmed” by humans to operate according to a fixed set of rules. One might ask, how then does a person communicate with the computer? For a start, it might help us to know a bit about the computer’s very own “natural” language, which is called the binary language; it is a very difficult language for us to understand (it consists only of 0s and 1s!). To avoid getting brain-locked for the rest of our lives (pun-intended), we have come up with programming languages, so that we can tell the computer how to function when given certain commands. A specific process translates these languages into binary code, so that the computer is able to follow the instructions. It’s the job of the computer programmers to come up with ways to get the message across to the computer.
We must then ask ourselves: how does a computer work? How does an ordinary user operate the computer and how does the system respond? To answer this question, first let us look at ourselves and see how we function. If I were to ask you a simple question: what is 1 + 1? You would answer: 2, immediately! I am sure many will be unimpressed by this example, but it’s only because we are taking it for granted. Observe. In this case, I am asking the question. You would read the question with your eyes, would think over it using your brain, and answer it using your mouth. It is a perfect example of input, processing and output, exactly the way a computer processes data! Now you know why I stress that a computer is like a human machine. We enter input via the keyboard, the CPU processes our data, and the monitor displays the output, just like the way this text has been written!
A computer has two primary components: hardware and software. Hardware can be defined as items that we can actually touch or move from one desk or room to another, such as a keyboard or a mouse; software, on the other hand, is defined as a set of instructions which tell a computer how to behave, such as Microsoft operating system. Software cannot be touched or heard. Again, this concept can be understood better by examining our own bodies; we have five senses, which include the senses of touch, sight, smell, hearing and taste. Our nose is the hardware, while the sense of smell is the software, which is connected to the brain (CPU)! Similarly, our eyes are hardware, while sight is software.
Now I would like to ask a question: what is a virus? The common cold is a virus; so is AIDS. But these are viral infectious diseases. So, what is it with computer and viruses? A computer virus is a program that can infect a computer by copying itself; it usually harms the computer’s performance. As far as characteristics go, it is very similar to the common cold. Consider, for an instance, that I have the common cold; I may develop a cough and have a sore throat. Thus, I won’t be able to play around like I usually do; this means that I won’t “function” well. A computer that is infected by a virus also cannot function as smoothly as it is expected to.
It does not make sense to talk of the computer and not mention Microsoft. It is the most popular operating system in the world. An operating system is a platform on which the computer runs. It’s like a person’s desk, on which files, notebooks, stationery and calculators are strewn; the only difference is that it is much more organized and detailed.
The conclusion is simple. Computer has been developed by Man, for Man, in its own image, and it has the abilities that Man could not only imagine but also formulate. Neil Armstrong could not have made it to the moon without the assistance of the computer, and neither would we have come up with ways to combat diseases like Alzheimer’s. Without it, we would still have been sifting through books in the library (rather than accessing online journals), scientists would have been involved in tedious paperwork (rather than using computers for complex calculations), and people would be glued to their televisions for entertainment. It is the baby of every student, the love of every scientist, and the need of the masses; it is the computer.