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Quantum Mechanics - Explained Fast

Quantum Mechanics - Explained Fast

If I was forced to summarize Quantum Mechanics in one sentence I would say this.. "small objects behave very differently than big objects".

It sounds like an innocent statement. But it's not. It's a profound discovery of how nature works.

An example will help..

Spin is something we're all familiar with. We can make any object spin. And not just a top, spin is used to great effect in many sports such as tennis, baseball and cricket. And of course you could never throw a frisbee without spin.

We can spin an object at any speed we please, and as soon as it starts spinning it defines an axis about which the spin occurs.

But that's the spin of a big object, meaning an object we can handle. What about the spin of a really small object such as an electron?

It turns out the electron spins just like a tiny top - but with two big surprises..

- What about the speed of spin?
The electron spins at a fixed rate that can never be changed. There is no known process that can change the spin rate of the electron. This makes electron spin a fundamental quantity.

- What about the axis of spin?
You can measure the spin along any axis you want and you'll always get the same result, +1/2 or -1/2 (these two values just correspond to the electron spinning clockwise or counter clockwise). So the electron behaves as if it's spinning about every axis at the same time!

So electron spin is totally different than the spin of a big object such as a top.

Physicists call the electron a "spin 1/2 particle". And it's not just the electron, all elementary particles have spin except for the recently discovered Higgs boson.

If you plan to study Quantum Mechanics pay attention to spin. It's a wonderful example of how "small objects behave very differently than big objects".

Content written and posted by Ken Abbott