Eli5 : If atoms are made of and separated by an incredible amount of empty space, why isn’t everything going through everything?
In: 456
Electrical forces of repulsion between electrons, mainly. Non charged things, like neutrinos from the sun, are sailing through us constantly, in staggering numbers.
you know the yoyo trick around the world? i want you to imagine somebody doing that, only instead of it going back to their hand, the yoyo is going around them constantly. now, imagine they have 6 hands, with 6 yoyos, all going in different directions. they all just barely miss each other going around and around, never stopping. now, imagine somebody else standing right next to them doing the exact same thing, with the yoyos of one just barely missing the yoyos of the other. what happens if these two people try to take a step closer to each other? those yoyos hit each other and tangle and knock each other away, right? those people each represent a single atom of carbon, with the yoyos being the electron clouds. if one person were to try to walk through the empty space of the cloud, they get knocked about by all the yoyos. nothing might be in a particular spot at a particular time, but anything can be coming from any direction to knock them away. now, something small enough and fast enough can and will pass through that cloud, like subatomic particles, shooting through like a bullet, but that’s getting into physics
These all sound like chatgbt answers. I’m sure they’re not but I can’t believe anything I read anymore gosh darn it!
The atoms resist getting too close to each other.
Imagine if you had a container full of magnets, but each magnet only has a positive charge. They will all repel each other and maintain a separation. If you move one of them closer to another they will all feel the force and shift.
There may be a lot of empty space, but the forces acting between them can still be felt.
To add on to what has been said, I just want to point out that you’ve never physically touched anything in your life. It’s all just been electron repulsion! Makes you question what it means for something to be “physical” huh?
In an atom, you have the nucleus the ball of protons and neutrons, and then a cloud or sea of the electrons floating around. These electrons are negatively charged.
Negatively charged things repulse each other, so when another atom comes close, it meets resistance, because both of their electrons clouds are the point of “contact”.
It’s very similar to how two magnets would repulse each other. Try to push two together and it will feel solid.
If you put enough energy or force in, you can overcome this repulsion. As in, if you pushed two things together hard enough, you could get their nucleuses to touch.
Only then you’ve just achieved cold fusion, and vaporised yourself
A very easy intuitive way of explaining is that clouds of electrons repel each other because they are negativity charged . There is something about uncertainty and orbitals but that’s confusing for some . Funny how covalent bonds are also electrons from the two atoms repelling each other.
Take a nut and tie it to a 4’ section of string and then whirl it around you 10 times as fast as would normally be humanly possible, then ask your buddy to walk through the empty space between you and the nut 4’ away from you. Your buddy is not going to have a good time.
Atoms are like this too, only instead of coming into physical contact with the spinning electrons, it’s repellent magnetic forces
Because the space isn’t actually empty, it’s just filled with fields rather than “objects”, as if a field isn’t part of an object.
Forces and sheer numbers. Specifically the electromagnetic force. Also, some things *do* go right through.
I’ll try to alternate back and forth between ELI5 and ELI20seekinganengineeringdegree
An atom has a very strong positive charge (the nucleus) focused on a very tiny concentration of mass.
That nucleus has a bunch of electrons orbiting around it, and they each have a negative charge. They’re attracted to the nucleus in the same way that a planet is attracted to the sun. It’s trying to fall into the sun, but it’s moving too fast sideways and its in a stable orbit of perpetually missing the sun.
Except there’s way more electrons than planets, and the orbits are not nicely behaved circles. They’re more like random spheres, toroids, and “[dumbbell](https://www.google.com/search?q=dumbbell+shaped+orbital&rlz=1C1GCEA_enCA1023CA1023&sxsrf=APwXEdcZEwGZZSlntHmQkqYGOhXO49HR-g%3A1685973144450&ei=mOh9ZLOJG9T3kPIPt6qA-AE&oq=dumbel+shap&gs_lcp=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&sclient=gws-wiz-serp)” shapes.
Anyways, the point is that the electrons move so much faster that it’s almost like they’re everywhere all at once.
Google [“drone racing”](https://www.google.com/search?q=drone+racing&rlz=1C1GCEA_enCA1023CA1023&sxsrf=APwXEdfzLopNo0kFU5xgu4QazGogtDMrhA%3A1685973628688&ei=fOp9ZKDWKbfykPIP3ZSkkAk&ved=0ahUKEwighPSZpaz_AhU3OUQIHV0KCZIQ4dUDCA8&uact=5&oq=drone+racing&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQAzIICAAQigUQkQIyCwgAEIoFEMkDEJECMggIABCABBCSAzIOCC4QigUQxwEQ0QMQkQIyBQgAEIAEMgUIABCABDIFCAAQgAQyBQgAEIAEMgUIABCABDIFCAAQgAQ6CggAEEcQ1gQQsAM6DQgAEEcQ1gQQyQMQsAM6CwgAEIoFEJIDELADOgoIABCKBRCwAxBDOgcIABCKBRBDOgsILhCABBDHARDRA0oECEEYAFDVA1jzB2DmCGgBcAF4AIABrgGIAdwEkgEDMi4zmAEAoAEBwAEByAEK&sclient=gws-wiz-serp). The drones, like electrons, are “orbiting” around the track. Try telling yourself “it’s mostly empty space” as you walk across the track though, and you’ll quickly realize your fallacy.
To get to the “forces” part of it, the electromagnetic force is easily described as “opposites attract” and “like repels like”. If you have two atoms with full electron orbitals (e.g. two Neon atoms), and try to push them together, they *don’t like it*. Remember how I said that the electrons are like being everywhere at once? They kind of form a “shell” or “cloud” around the positive nucleus. That means that the nuclei are well guarded, and the atoms might as well be two balls with negative surface charges. The electron clouds repel each other, and don’t let them get close to each other. In fact, they’ll never touch.
The closer these atoms get, the stronger the force is, and this force is *insanely strong*. When a blacksmith hammers a glowing strip of iron with a hammer over an anvil, *nothing is actually “touching”*. The atoms in the head of that hammer are repelling the atoms in the metal so strongly as they get close together that they never actually “touch”.
Aside: When atoms form molecular bonds, they actually “bond” by sharing a pair (or 2, even 3 pairs) of electrons. Often each atom will provide one of the two electrons needed, and those electrons will form an orbital that encircles *both nuclei*. These electrons orbiting around (in what you might choose to think of as a ‘figure 8′) help keep the bonded atoms’ nuclei a stable distance apart. When two or more atoms bond to form a molecular structure, each atom has most of its electrons orbiting itself, and there will be a handful of electrons that orbit two or more atoms in the molecule, effectively forming an electron “shell” around the entire molecule. Because of this, the examples given above for atoms applies just the same to larger molecular structures as well.
In solids, atoms and molecules are bonded together through shared electron orbitals or ionic bonding, and they’re rigid with each other. If you want one more hilariously silly example of solids colliding, imagine two armies marching towards each other. Except they don’t carry shields and spears and march shoulder to shoulder. Instead, each soldier stands two meters apart from the next, and instead of soldiers, they’re all yo-yo masters doing all of their wildest, most violent tricks. Two armies of yo-yo masters marching towards each other. Both armies are “mostly empty space”. But there’s no way they’re getting through each other without some yo-yo on yo-yo interaction.
Then there’s light and other electromagnetic radiation, doing pesky EM radiation things.
Light is a photon, and while it carries energy, it’s not a charged particle itself. However they do kind of do weird things with the electromagnetic force, and this is where my knowledge and capability of explaining hits a rough patch.
The ratcheted down explanation starts with a science history lesson. Don’t sneeze because you’ll miss the whole lesson: For a long time, scientists couldn’t agree whether light was a wave or a particle. It very clearly exhibits properties of both. Turns out the answer is pretty much that photons wiggle as they zip through space and time. Yep. They wiggle. They act like particles shot out of a gun, except they wiggle and that wiggle also forms wave patterns making them behave like both a particle and a wave. There. Now you’ll actually know where the professor is going when they take 2-3 lectures to explain properties of light.
For pretty much all solids, there are particular wiggly patterns for photons that let them through. Essentially, the orbital patterns of the electrons in the solid need to be compatible with the wiggly pattern of the photos, otherwise they bump into each other and interact, often with the photons just being “absorbed” by the electrons, which speeds them and the atoms up, releasing energy as heat and/or re-emitting photons. I believe this depends on the composition, density, and crystal structure of the material. It’s what lets visible light pass through glass while not through an even thinner sheet of aluminum foil, and it’s what lets only red light pass through rubies and blue through sapphires.
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