Just what IS Quantum mechanics?

This is a question that has been been asked many, many times.

Now, let's get one thing perfectly straight - the "mechanics" bit up there bears no resemblance to the kind of mechanics we usually talk about, such things as engines, nuts, bolts, screwdrivers, wheel- balancing, etc.

True, it is the same word, but in physics it means something very different and quite specific: "mechanics" in physics is nothing more than the study of the relative movement of things, like apples dropping from trees, billiard balls moving on a snooker table, and the occasional hammer hitting someone's head.

Nothing to do with cars or anything Richard Anderson might say in "Forbidden Planet".

A lot of the time, mechanics just deals with things hitting each other. When I say "deals with" I mean we use equations to find out where they will go next.

For example, what happens when two billiard balls collide, head on? Well, if one is standing still, the moving one hits it and transfers the motion, and the second one moves off.

In an ideal world, yes, but this is not what happens. It so happens that both balls end up moving. "How can this be?" I hear you ask. The answer lies in the way the balls are put together and what they are made of, BUT that is the realm of materials science, not physics.

So mechanics is when things hit other things. Now we're getting someplace, as Ollie would say.

There are different types of mechanics, all of which use the basic "mechanics" laws set down by Isaac Newton. There is Celestial Mechanics (how large things like planets behave), Terrestrial Mechanics (hammers hitting heads), Car Mechanics (nothing to do with this discussion), and Quantum Mechanics (how very small things behave, things like atoms, etc). Oh and there is Relatavistic Mechanics, and Relativistic Quantum Mechanics, too, but both these only come into play when you are travelling just a tad faster than Richard Hammond did last year.

So, WHAT is Quantum Mechanics? We, like I said, it is "how small things behave" but there is more to it than that. Scientists thought terrestrial mechanics ruled ok, ino questions asked, including the very small. The fact is, we had to invent a completely new branch of Mechanics, so as to predict where things ended up after the charabanc. The reason was, the very small particles acted in very different ways to what we expected. They actually acted like "waves". Hard to believe , ain't it? Moreover this "quantum Mechanics" gave right answers for all the other mechanics branches as well.

Depending on the experiment you were doing , the very small particles act both like "waves" and "particles". It is very hard to imagine, and even to this day 99% of scientists don't really know what is going on, BUT, what they DO know is how to predict what will happen when two of these "quantum" billiard balls collide, and what happens afterwards. Very clever.

So where does that leave us? Well, to the ordinary layman, you or I, it means nothing, because we as people are never going to deal with things THAT small ( I am saying nothing about Marvin's brain here), but some scientists have to deal with this every day.

They are called "particle physicists" and live in very tall ivory towers in Geneva. I, the layman (or laywoman) deal with particles just as small, but I am only called a lowly "nuclear physicist".

However, I still find fun mucking about with the equations in our computer programs, investigating "Quantum Mechanics". It is almost all a little girl can do.......

So, when it comes down to it, we have a perfectly good representation of the world as we know it with "Terrestrial Mechanics", so why do we need "Quantum Mechanics"?

A good question, and one which deserves an answer. With no Quantum Mechanics, we would not have discovered Light Amplification by the Stimulated Emission of Radiation, or the LASER. There would be no nuclear or particle physics, ie neither the Atom bomb nor the Hydrogen bomb would have been invented. Is that a good or a bad thing (bad for me, anyway!) - one for the philosophers, I am sure.

Another thing is that wihout Quantum Mechanics, we would have primitive computer controls still, the most important of all would be - no DVD's CD's etc, Guided missiles would be out too, as would be supermarket checkouts. TV remotes. The road goes ever on.

Maybe the most important thing we would be missing would be the Josephson Junction in electonics, but I wll leave the reader to find out what is THAT by himself.

Shrodinger will never know what a Pandora's Box he opened!

Holmes, I have a sore neck....

Another wonder of the world is genetics.

Genetics appears to be the science of studying the very building blocks of life.

It involves this: all living things are made up of stuff called DNA. DNA is just an abbreviation for a very long molecule (molecule = collection of atoms), called De-oxy ribo-nucleic acid. The wonderful thing about DNA is basically that all DNA is quite similar.

DNA is made of only four different types of smaller molecule (Cytosine, Guanine, Thymine and Adenine, or C, G, T and A, called "bases") and it is the way these are combined that make each bit of DNA different.

Surprising thing is, the DNA is just like a line of these, all in a row, and it is the order of these four that determines what the DNA does. Trouble is, the DNA is very long, miles long, in fact if a hyperbole is needed.

So what's with this DNA? Well, it is just an ordinary molecule, except that it is very long.

One more thing, and this is the good bit, the scientists found that DNA could make other molecules of DNA, all by itself.


How can that be? I can hear the reader ask. Good question, I must say, because if a molecule is going to make another molecule, it could be anything and indeed, if statistics are anything to go by, physics says it WOULD be anything.

However, DNA is very special, in that the molecules it makes are exact copies of the sequence of bases it uses itself. In other words, DNA make copies of itself, the exact copy.

This is why things grow, because the "lifeform" makes more DNA for itself to add on to the original.

The Big Question is: why does DNA make a copy of itself and not some other useless molecule, and how does it do it?

This is a question asked by scientists ever since we discovered that DNA was the molecule of life.

The answer was provided by scientists Watson and Crick in the 1950's.

It was a code!.

What happens is this: The DNA sequence makes another molecule called an enzyme, and this enzyme gathers the correct bases to stick to one half of the DNA, which is divided into two. The whole process creates two molecules of DNA, which are exact copies of one another.

So how does the DNA know which enzyme to make? Simple, a code!

The sequence of the bases in any DNA molecule is a code to create the correct enzyme that enables a copy to be made.

Wait a minute! A code? Aren't codes a thing of design?

Hmmmm.

Here's us scientists thinking that evolution brought about all life by chance! But if that were so, how come a code got in there?

Maybe, just maybe, there is a designer after all, and the world have been calling HIM names from antiquity, names like Yahweh, Brahmin, Buddha, Allah without knowing why.

Makes you think, does it not?