You may have heard that things get weird at a miniature scale.
Zoom in on any material with a microscope and you will see that it is made of tiny atoms made up of electrons and protons, and that it pretty much follows what you know from science.
Weird yes, but not all that shocking.
However if you were to take things further with an electron microscope, some maths and some experimentation, you’d find that things are actually a lot stranger than that. In fact you’d find that things got so strange that they challenged everything you might have previously believed about physics and about the universe. Here the laws are so different, that scientists have had to draw alone between what happens on a sub-atomic scale and what happens in the observable universe. In the latter we rely on classical ‘Newtonian’ physics, and for the former we use what’s known as ‘quantum physics’. Read on to learn the difference.
Everything you know is wrong
Firstly, forget that picture of the atom with the electrons and protons orbiting the nucleus like a planet and its moons. For starters the relative space between the nuclei and electrons is so large that you could never represent the distance on a piece of paper – they’re far from tightly packed as you might imagine. Matter it turns out is mostly made of space, and if you were to compress it all down so that there were no gaps between the particles, the entire human population would be tiny enough to fit inside the volume of a sugar cube.
What’s more, particles do not ‘orbit’ the nucleus of an atom – in fact they exist all around it at once as far as we can tell…
Particle or Wave?
The uncertainty principle states that it’s impossible for us to know the exact position of a particle and its precise speed. The reason for this is simply that there is no way to observe it that doesn’t cause it to move – electron microscopes (the type of microscope that can observe electrons) for instance require you to shoot other electrons at the particles in order to measure them which of course affects their speed.
But more worrying is the fact that particles seem to change their behaviour simply through being consciously observed.
This is demonstrated in the amazing ‘double split’ experiment where researchers fire electrons through a slit in a sheet of material to hit a board at the back to record where they make impact. This creates a scattered pattern with the outline of the slit being visible where the electrons passed through the gap as you might expect.
But then, if you have two slits in the sheet the electrons seem to pass through in a different way – creating an ‘interference pattern’ on the back board in the same way as a wave. This would suggest the particles passed through both slits at once and demonstrates how in quantum physics something can behave like both a particle and a wave at once.
Is reality subjective?
Things get even stranger though when you start recording the particles as they pass through the slits. Set up a tiny ‘camera’ to watch them as they pass through the slits and suddenly they begin behaving like electrons again – leaving two thin strips and a scatter pattern around them on the back board.
This isn’t to do with the uncertainty principle, rather it seems as though the act of observing the particle when it’s a wave will make it into a particle giving it a fixed position and speed. Prior to that point it exists as a wave and exists in many places at once – it’s only possible to workout the probability of it being in any fixed position.
So, our picture of the atomic world is completely wrong. Atoms really look like a nucleus with a kind of ‘haze’ around them, stretching out further than you can imagine. And they completely change, as soon as you look at them…
This article is contributed by Roy King, a marketing executive at Omega Scientific Pty Ltd, renowned providers of microscope glass slides. Roy is a culinary enthusiast and specializes in Mexican cuisine.