I understand the math of the equation — mathematically speaking, the more certain you are of electron location, the less certain you are of velocity, and vice versa. But why? Do we know why this is a thing for electrons? Is here any hope of resolving this or does it appear to be an immutable characteristic of particle physics?
I’m tagging it Chemistry, because I’m primarily trying to understand it in terms of chemistry principles rather than physics principles because that’s how I need to apply it.
In: Physics
One famous way people look at it is that electrons are so small that to observe them, you’d shine light(photons) on them and that would tell their location correctly but in the process have changed the momentum.
Mainly the problem is that observation, since it requires inteaction with what is being observed, is an inherently destructive process. It interferes with the state of the system. Thus there is a limit to how much of the system can be known without interfering with it.
It is almost a comment on our power to observe and know and what it really means to measure.
Heisenberg’s principle really isn’t all that complicated nor unusual. It is a very simple observation about the nature of time and waves.
Let’s take the example of the momentum/position pair. Momentum is the description of movement. Time is required to make sense out of any movement. The position is the opposite: when describing the position of a moving object you need an exact point in time.
Together they are contradictory – if there is no time, there is no movement. If there is a perfect position, there is no time.
Similarly for the energy/time pair. Energy is derived from the wavelength of the object. But without time the very idea of a wave simply doesn’t make any sense at all. Therefore, if you reduce time to zero for perfect precision, there are no waves, and without waves the idea of energy stops making sense.
It isn’t just quantum physics, it applies to normal life as well. For example, if you take a photo of an object at a very short exposure time you have no idea about its movement. It looks completely still. If you increase the exposure time you can see the object moving, but the photo is smeared so you can’t really say where the object was during the shot.
The constantly forgetten assumption is the “with our current technology.” A few years back (sauce: Google/Duck/Bing it) a technique was developed to measure one aspect with less disruption of the other.
People just treat HUP as magic because they forget or don’t get told the assumption.
You can’t understand it with chemistry alone, because it’s physics, plain and simple. Chemistry is physics too, but at the slightly higher scale of interacting atoms.
The Heisenberg Uncertainty Principal is a property of waves and wave pulses. Anything that has wave properties will have a similar phenomenon electrons included.
Imagine that you have a perfectly periodic wave. You know the ~~amplitude~~ frequency, not sure why I said amplitude (energy/momentum) exactly, however, there’s no information about the location of your wave, as it exists along the entire line.
Now imagine the reverse, you have a single, infinite peak at your origin. You now know exactly where your wave pulse is, but no information about the energy.
Then, you can smoothly transition between these two extremes, and you’ll find a tradeoff between how much you know about position and momentum, or time and energy, or other Heisenberg relations.
This is physics, and physics is all about your world view. We think of an electron as a little point particle with a certain electrical charge that orbits around a nucleus (and such things that mimic larger objects that we expect to be able to nail down where and how fast they are moving), which is perfectly acceptable if it helps you understand a problem. Or we think of electrons en-mass (where we have aggregate or bulk properties of many electrons, like electrons stuck in a capacitor). But those world views falls apart if you start looking closer (at single electrons), when the quantum world views start to dominate. Here an electron can behave like a wave (traveling at the speed of light) and/or a partical (look up dual slit experiment). If you want to know where the electron is in its orbit around a nucleus, you wont find it because it’s everywhere in it’s orbit (see probability clouds).
At quantum levels, particles are really described as probabilities or waves, which are subject to Heisenberg’s uncertanty principle (which is not exactly the same as the observer effect) because they are not actually particles.
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