Quantum Mechanics

So last Chemistry class we were given our first doses of Quantum Mechanics... headaches ensued. One reason for this is that there were many new, radical ideas presented to us, and there wasn't much explanation.



This was one of the videos we watched. This video really makes the reality of it seem weirder than it is, because it is over simplified. It reality, the electrons don't change from being a wave to a particle simply because they know they are being watched... observing a particle requires interaction between the particle and the detector, essentially changing the detector in some way (triggering a 'detection') and also changing the particle itself. Changing the particle could have any number of effects, most of which would likely interrupt the wave-like behavior. Normally on our macroscopic scale, we think that observing something doesn't have to change the object being observed in any way, and that's because truthfully it doesn't noticeably. But I would imagine that one photon of light (what is hitting your eye, the detector) bouncing off of an object(what you are looking at) would somehow alter what ever the photon is actually hitting on the subatomic scale.

The idea that a particle - sorry, particle-wave - like an electron can have all its states in superposition at the same time is an interesting concept. It is like nothing we observe on our macroscopic scale. It almost reminds me of my confusion starting Algebra. I had a little bit of trouble understanding how one variable could represent more than one thing at the same time, especially when you can only evaluate it as one thing at a time. Accepting the concept was no problem at all, but understanding it was. There is definitely a difference between accepting a fact to be true, and actually understanding that fact. Unfortunately, most of quantum mechanics is something we as chemistry students will have to simply accept to be true, no matter how little sense it makes.

Quantum Mechanics is based off another new idea that is unobservable in our macroscopic scale - that the electron energy levels are 'quantifiable' and that there is no 'in between' electron energy levels. This sort of concept, however, is not so hard for me to understand. Relating to stored computer values, there are many types for which there are no 'in betweens'. For instance, certain things can be only true or false. There is no in between true and false, its either one or the other. More commonly, if you thought of letters of the alphabet as values, then there is no letter in between 'a' and 'b', so letters of the alphabet are also similar to quantifiable values. But the fact that the position of the electron physically is quantifiable - that there is no in between electron energy levels - is something not so easily related. There is nothing in the macroscopic scale that works in the same way. To get from a to b, you must go through the space in between a and b (unless a was infinitely close to b). So for an electron to go from a to b, and skip the in between, does not make much sense.

I mentioned in the above paragraph that the behavior of wave-particles is nothing like anything we have on the macroscopic scale, which is yet another thing that fascinates me and at the same time perplexes me further. It's as if the atomic scale is bound by completely different rules than our scale. Like it's a whole extra world. And why? Why should laws which hold true for anything on this scale not apply for the atomic scale? Where is the line drawn?

Finally, I am very reluctant to accept that probability rules over the quantum world. In my mind, probability and 'randomness' are abstract and illogical ideas, that don't truly exist. If you knew enough about a given situation, you could predict it's outcome. The problem with the quantum scale is that it is impossible to know about the given situation in the same way it is on the macroscopic scale. Where as on the macroscopic scale we are limited in predicting the outcome of a coin flip by impracticality, on the quantum world we are limited by the very laws of physics. It is my personal opinion regardless that there is a difference between unpredictability and true randomness.


Despite all the uncertainty, I must say that all the confusion over waves and particles has really helped clear up what exactly was meant by light being a wave. I wasn't quite sure how to interpret or visualize it before, but it is perfectly clear now.



Seriously, if you are reading every word of all these, I'm really sorry and I wish I could make it up to you somehow.