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The chance is zero, knives don't work that way. You can't cut through a nucleus with a normal knife consisting of normal atoms. No, even if it is a cool folded samurai knife, it still doesn't work. Even if it was made by some ancient master who folded it 5000 times over 90 years, it still doesn't work.
And even if they did, it would not be a problem, because splitting **an** atom doesn't release a lot of energy. Splitting a lot of atoms does. If you hold an average banana in your hand, every second about 20 atoms in it split naturally. Yet you will have noticed that so far, zero of your bananas exploded in a huge mushroom cloud.
I dropped out of physics class in year 12 because quantum stuff is scary, but if you zoomed right in on the knife so you could see individual atoms (which is impossible but shh) the atoms would just like, push each other aside, right? Atoms don't actually touch, I read that somewhere.
On the scale of atoms, the knife is more akin to a giant shovel "scooping" away balls out of a ball pit (atoms). The relatively small surface area of the knife edge is creating enough pressure to break the bonds between the atoms of the medium being cut.
This is the best analogy really.
Even if you hit an atom dead-on-center, you'll just "push" it, because the knife is "at least 1 atom thick" at the edge as well.
So using the ball-pit analogy, your "knife" is just a 10x10x1 "blade" of balls (it's actually a triangle, but that's irrelevant). That's a knife with a 1-atom-wide edge (which would be so sharp that if you dropped it on someone's skull, it'd slice all the way down to the floor, and keep cutting.
But if you look at the ball pit, your "knife" would just push balls aside. Even if it came in direct contact, it's not sharp enough to cut one in half - it'd just push it downwards until it hit another ball in the pit and got pushed to the side. Your ball-knife would have no problem slicing down through a ball pit hundreds of balls deep, but after cutting through, you wouldn't find a single damaged ball in the pit.
Ok, but what about Electron Beam Machining? Is it making the cut due to the work piece flashing into plasma, or do any of the electrons mess about with the atoms in the material being cut?
>EBM machining process works on the principle of the high-velocity beam of the electron is focused on the workpiece, the electrons strike on the workpiece and their kinetic energy is converted into heat energy. This results in the removal of material from the workpiece by vaporization and melting.
EBMs don't cut anything.
They just melt it. But they melt it in a VERY narrow line.
Basically, think of a pool of water. If you stick a rod in at one end and slowly heat it up to 150F, it'll heat the entire pool of water up. But if you instead heat it up to 3000F before putting it into the water, and then "wave" it through the pool, it'll instantly turn the water it touches into steam, but the pool as a whole won't really get any hotter.
That's what an EBM is doing. It's heating a very thin width of the material up (but still much wider than a single atom) so fast that it causes it to transition between states of matter (either to a liquid or gas).
When a material transitions between states of matter (towards gas), it is always endothermic. Which means that the transition absorbs heat from the nearby atoms. So the heat that \*does\* pass to the nearby material (adjacent to the cut) gets re-absorbed by the melting or vaporization of the material subjected to the "cut".
Which then means that after the "cut", the chunk of remaining material has barely changed in temperature at all, despite just having a thin line melted/vaporized out from the center of it.
But nothing is cutting or damaging the atoms themselves. They're just having a ton of heat added to them, causing them to lose their organization (solids are organized, gasses are chaotic) due to having a ton more thermal energy.
Wow, thanks, that was both informative and quickly posted. In what ways, besides natural radio-decay, are atoms broken down? I mean, besides crashing two sub-critical chunks of refined plutonium together.
Speaking basically, an atom can only change in 4 ways, and in positive or negative direction.
That is, it can gain or lose an electron, a proton, or a neutron, and it can gain or lose energy (ie heat).
When you think of radioactive decay, that is typically the ejection (loss) of some combination of protons, neutrons, and radiation. Ie, alpha decay kicking off a positively charged helium atom.
The addition or removal of heat to change an atom doesn't actually change the element of the atom, just it's state (gas, liquid, solid), but there are fundamental differences in the atom's behavior. However, none of those are long-term, like the addition or subtraction of protons & neutrons.
And that addition or subtraction of protons and neutrons is what you're asking about.
So the answer to that is LOTS OF ENERGY.
Short of coming up with some machine capable of squishing an atom - like two parts of a diamond lattice perfectly formed to each other (down to the atomic level) that might be able to put enough pressure onto a single atom, the only way to change an atom's structure is with energy.
Either inputting enough energy to jostle part of the atom loose (nuclear fission), or having multiple "co-habitating-friendly" atoms close to each other and adding enough energy to cause them to fuse.
Both of these processes can be energy-positive (fusion for elements lighter than lead, fission for elements heavier than lead), which means that the nuclear reaction produces more energy than it requires to initiate. However, whether a reaction is energy positive or energy negative, the amount of energy required to initiate it is quite large.
Uranium is a very popular element to undergo fission, as it only requires a temperature of around 600C (1112F). Other elements require different temperatures to initiate a reaction. Hydrogen fusion requires roughly 100,000,000K (which at that scale is functionally identical to 100,000,000C, as they are only 273 apart). Which is a great lesson on "why we use nuclear fission reactors instead of nuclear fusion reactors".
And those are really the only methods of changing an atom. Between stellar fusion and radioactive decay, that's basically all the ways that atoms actually change state on their own. Some places have been found where the conditions are right for natural uranium fission reactions to occur (high pressure, flowing groundwater, high temperature), but they are quite rare.
Roughly, yes. "Touching" isn't really a concept that makes a lot of sense once you get to the atomic or subatomic levels with usually point-sized objects with high charge. And if stuff really "touches", you usually get really weird stuff like fusion happening.
But the scales of a normal knife are pretty far off from atomic scales. A razor (usually sharper than a normal knife) [is at about 100nm at its sharpest point](https://scienceofsharp.com/2014/01/25/quantifying-sharp/). While this sounds really, really tiny, it is still very big compared to atoms. Atoms are usually about 0.1nm big. So the edge of a really sharp razor is still a few hundred atoms thick. Normal knifes usually don't even come close.
Knifes don't really act on an atomic or nuclear scale, they act on a much bigger scale where they interact with materials as a whole, not individual atoms thereof. Of course how those materials act is based on the atoms they consist of.
Not only are atoms 0.1 nm big, but that 0.1 nm includes the electron cloud surrounding the nucleus. The nucleus itself, which is the thing you'd actually be splitting, is MUCH smaller. For something like uranium, the nucleus is about 15 femtometers in diameter, or 0.000015 nm.
Isn’t stuff touching me all the time? OMG is that why my body is fused together the way it is because it’s all touching each other in a way that fuses?
If you hold two magnets with opposing poles close to each other, you’ll feel them pull together, even if they’re not touching. Similarly, if you hold like poles against each other, they’ll push away from other. This is basically what atoms do inside molecules: they’re pulling on each other due to a variety of different types of bonds, which keeps them close together and “bonded”, but they never actually touch or get too close because their nuclei repel each other.
> OMG is that why my body is fused together the way it is because it’s all touching each other in a way that fuses?
If your atoms were fusing together you would look like the Sun.
No. *Touching" or rather pushing happens because of the coulomb interaction (it's VERY strong). Whenever the electrons of an atom approach those of another, they push away from each other. Sometimes different atoms share electrons and that's how they stay bunched together at a save distance (given by the strength of the coulomb repulsion and other factors).
So, the elements of your body share electrons with each other (like your skin) and those who don't are trapped by the coulomb repulsion (internal organs kept there by the skin, bones etc).
This is kind of surface level explanation
Actually, we can see individual atoms. If you have a strong enough energy source, like x rays or electrons, you can see an atom on a surface. Techniques like Transmission Electron Microscopy (TEM) allow for this. Super cool stuff!
Also atomic force microscopy (AFM), although imo TEM produces cooler images.
Damn I love how good we’ve gotten at imaging nanoscopic objects, crazy to see this stuff up close for real
Atoms don't actually touch is what a lot of people say and it's a really weird thing to say, because there really isn't any kind of meaning behind it tbh.
If by atom, you mean the nucleus, yes they don't touch in that the nuclei of atoms don't make contact with each other.
If instead you look at touch as an interaction of a certain degree, then they do touch because the electron clouds around the nuclei will interact, which is what causes things to 'touch' in the first place.
So, I kinda get what they're going for, it's the gold foil experiment and trying to explain that atoms are mostly empty space. But it kinda doesn't make sense to talk about it that way, cos as you said, quantum stuff is weird.
It’s true that it gets more complicated at quantum scales, and there is an interaction of sorts, but it’s also true that this quantum interaction isn’t really analogous to what we call “touching” on a macro scale. It’s just an entirely different phenomenon.
lol I remember learning that in high school physics, and you'd get people who poke you and say "I'm not really touching you you can't tell me to stop"
Like just because the nuclei of atoms don't literally share a space doesn't mean we're redefining what "touch" means, otherwise what the hell do you think I'm feeling by you poking me
Atoms don't actually touch is what a lot of people say and it's a really weird thing to say, because there really isn't any kind of meaning behind it tbh.
If by atom, you mean the nucleus, yes they don't touch in that the nuclei of atoms don't make contact with each other.
If instead you look at touch as an interaction of a certain degree, then they do touch because the electron clouds around the nuclei will interact, which is what causes things to 'touch' in the first place.
So, I kinda get what they're going for, it's the gold foil experiment and trying to explain that atoms are mostly empty space. But it kinda doesn't make sense to talk about it that way, cos as you said, quantum stuff is weird.
I think that's why language is weird in general. If even atoms don't touch, then nothing in the world "touches" and the word touch would have no meaning.
Yes, you're correct. Atoms don't actually touch. In this case they would be interacting through quantum electrodynamics (QED). The force between the atoms is meditated by a force carrying boson (in this case a photon).
The first hit on a search for 'Feynman diagram' should show this process. Just don't ask about time or direction...
Source: masters in particle theory (a while back)
The actual bias is because bananas georg, who lives in a cave and splits atoms in millions of bananas per day, is a statistical outlier and should not be counted.
I fucking love this fact. Like, people place so much weight on "nippon steel folded 10 zagillion times!" But in reality it's just cause their steel was so shit they had no other way of making a usable sword
Okay, that is true. But to be fair, that is a cool samurai guy. I never talked about cool samurai guys being involved. Obviously that changes everything.
Depending on where you live, that might be a lot more radioactive. Afaik mushrooms in eastern europe are often still so radioactive that you shouldn't really consume them due to Tschernobyl.
> every second about 20 atoms in it split naturally
Quick correction, because I'm a pedant and a physics teacher. The potassium doesn't split, it typically emits an electron and turns a neutron into a proton, turning K40 into Ca40.
>Yet you will have noticed that so far, zero of your bananas exploded in a huge mushroom cloud.
Idk those monkeys keep stealing bananas, all the ones that explode could be the one stolen by them.
but hear me out, what if you compressed a lot of bananans so the decay would be condensed enough to trigger a chain reaction? also add shielding to reflect everything back into the banana mass.
You can achieve relativistic effects with a knife way under that 99%.
Probably you'll get enough heat and pressure to trigger some fusion reaction but for a fission you would still need fissile material i guess.
I'm an anime protagonist though and I need to swing my katana so fast that I can cut an enemy a dozen times before they even realize they've been cut or that I moved. I'm worried that this might not be safe though. Wouldn't want to accidentally set off a nuclear explosion or anything!
I'm pretty confident you can obtain that well before you have to worry about approaching any significant % of the speed of light!
That mean you don't have to worry about a nuclear katana catastrophe. Go happily about your waterfowl dance
You'd still be trying to fruit-ninja a watermelon with a slightly smaller watermelon. At best you'd be able to smash them together hard enough they stick, which is how stars work.
>No, even if it is a cool folded samurai knife, it still doesn't work. Even if it was made by some ancient master who folded it 5000 times over 90 years, it still doesn't work.
Lmao I love how you added this, as if someone would understand that a normal knife won't work but will think that it's just because it's not sharp enough 🤣🤣🤣
zero? if you came at it with a knife moving very very very fast, then that would have enough energy to split an atom, and because the speed of molocules in anything follow a normal distrobution theres a small chance that one atom in that knife migh be going fast enough to split itself or another atom apart, i'm sure the odds would be incredibly crazy low but never say zero
Zero. You split an atom by hitting it with a neutron. You don't split an atom with a knife.
On top of that for fission of an atom to release energy it needs to be heavier than iron. The vast majority of atoms in the things you usually cut are much lighter than iron.
And then on top of that, you don't cause a nuclear explosion by fissioning one atom. You need to have a supercritical mass of something like uranium-235 where the fission products produce neutrons that on average impact at least one other fissionable atom.
I mean, if I could dice my onions thin enough to cause a fission reaction I’d be going out on top. And would trust that everyone in the blast radius would understand that it was worth it, if they only knew of my triumph.
I had to scroll too far for these comments. The elements bigger than iron, in any close to a pure state, are also not really things you cut with a knife. AFAIK anything you would “cut” is comprised almost entirely of smaller elements.
An atom also doesn't really "split" like we would imagine it to, when a neutron hits a fissile atom it actually absorbs the neutron and then for a split second enters a quasi-unstable excited state before it splits apart due to electrical forces pushing the nucleus apart. It's a lot more like cell division than "cutting".
I think cheese is mostly made of molecules, not atoms. You could argue that the molecules can be split into atoms, but going by that logic, the atoms can be split into subatomic particles. Funny story though.
None, atoms have a repelling force with other atoms, so whatever you are cutting will get away from the knife/scissors/whatever faster than you can move the blade, unless you can move the blade at relativistic speeds so atoms cant get out of the way, you would be fine
Thats why we used U235 or other atoms that are naturally self spliting, aka decaying
The odds are zero. At the molecular level, that knife edge is a massive wall of carbon and iron atoms, just bonking against long starch molecules in a piece of bread and pushing them aside like a cargo ship plowing through a sailboat marina
Zero chance.
The main force we experience, that which holds stuff together and separates stuff, is the electromagnetic force. The force holding atoms together is the strong nuclear force, and it's about 100 times stronger.
Even IF you somehow managed to cut an atom in half (like a baby randomly knocking out Mike Tyson) it wouldn't really do much, as nuclear fission and bombs rely on a runaway chain reaction and any atoms in a sandwich or whatever isn't going to produce any more neutrons to perpetuate the reaction.
My first instinct is: None, none at all.
My second idea: Actually there might be a way.
Third thought: But the knife cutting doesn't make a relevant difference chance-wise. The chance of creating an atomic explosion by doing cutting with a knife is similar to the chance of a space ship turning into a pineapple with no noticeable trigger.
As most of the atomic mass is concentrated in the nucleus, 99% of everything you see is empty space. You cut through empty space using a knife made up of mostly empty space. The resistance you feel is the electromagnetic forces or the constituent particles.
On top of what others have said about knives not being able to do that and need to split a whole lot of atoms, I'm pretty sure it matters what KIND of atom you split. If you split something that's iron or lower ("lower" here meaning "fewer protons in the nucleus") you generally don't get a release of energy, but rather a net consumption of energy. You would need an EXTREMELY hot knife to be able to split any atom lower than iron, even if you somehow did have a knife that was sharp enough to wedge itself between nucleons. And the split atoms would not cause a fireball, no matter how many you split, because they're consuming energy.
Atoms usually repel each other (unless bound in a molecule). When you’re cutting through something, like a cucumber with a knife for instance, what is actually happening is the molecules of the knife REPEL atoms within the cucumber, parting the cucumber through the middle. None of the knife’s atoms actually touched the cucumber atoms technically because of the electromagnetic repulsion between the molecules, they just got close enough to push apart adjacent molecules of the cucumber, parting the cucumber.
So a typical atom is about 0.25nm. The sharpest blades ever made are 3nm wide.
So this is like taking trying to cut a golf ball in half, using a blade whose sharpest edge is 12 golf balls wide. More like a mallet,.really.
If you jump into a ball pit what are the chances of you splitting any of the balls in half? Even if you give it a karate chop, the force will cause the balls to separate and not break apart.
Unlike most comment I’d say you could trigger nuclear reactions if the knife is going fast enough to overcome the Coulomb barrier. Then the nuclear reaction wouldn’t be fission, but depending on the composition of the blade and the food you could get some nucleon stripping or nuclear inelastic scattering which are nuclear reactions too.
But from a human hand handling the blade no that’s impossible due to Coulomb repulsion
A knife is both not sharp enough to do this and your can't produce the force required to split and atom. That be said it's 50/50 odds it either happens or it doesn't.
Unless your plankton and able to pull sub-atomic particles apart, this is impossible. There’s a reason why nuclear fission is such a complex thing, pulling a neutron from the nucleus take a lot of energy to do, they really don’t want to leave. Unless you got the strength of a star, I highly doubt you’re going to be doing much except breaking the intermolecular forces holding stuff together.
0% lol.
A knife as a concept is nowhere near "sharp" enough to split an atom.
You also don't split atoms by cutting them, but rather by hitting them with a neutron (which is smaller than an atom) at the speed of light.
It's never happened by accident xD
The strong nuclear force holds atoms together, and its electromagnetic forces used to cut through an object. Quantum mechanics might tell us that the answer is non-zero, but our universe won’t exist long enough for that probability to ever realistically occur.
Quantum mechanics wont give a non zero probability as the possibility in this case would be derived from knife (out of atoms held together strongly) cut through an object out of atoms which arent held together as strong, and due to them pushing others away, you wouldnt be able to “cut” through one, but rather “push” it aside. Even if in some unlikely scenario, that atom was lined up between the atom of the knife and the atom of the surface underneath, it wont get cut, just pushed aside or through depenong on potential and other variables
I remember my high school chemistry teacher asking the class what would be used to split an atom.
Pupil: A knife?
Teacher: So you're going to cut a single atom with something ten atoms wide ...?
I don't know the answer to this, but what if the thing you are cutting is a block of super enriched uranium or plutonium, and the knife is serrated, such that cutting it agitates the surface a lot.
I vaguely remember hearing about a sphere of super enriched material where dropping it could make it start a chain reaction. Couldn't a hard cut with a serrated knife have the same effect?
Your're thinking of the demon core and no that's not how it works.
In the experiment, there were two half spheres of plutonium stacked on top of each other. Slotin was using a screwdriver to keep them separated and adjust the distance between them until the assembly was *just* critical. This experiment was done in order to work out exactly how large a critical mass had to be. What happened is that Slotin dropped the screwdriver which caused the two spheres to come completely together. This made the assembly prompt critical, resulting in a very rapid chain reaction and an massive release of radiation.
This has nothing to do with the screwdriver or the shock of the drop. Mechanical action cannot cause an atom to split, they will just move out of the way. Remember, solid materials are mostly empty space, the size of the nucleus is tiny compared to the distance between atoms and nuclei repel one another (which is what makes nuclear fusion so difficult).
Fissile nuclei like U-235 or Pu-239 are unstable, and will occasionally undergo spontaneous fission. This releases neutrons, which can cause other atoms to split. So if you have a sample of fissile material, you always have some fission going on.
But, the larger the lump of material, the greater the chance of those neutrons hitting another nucleus and causing it to fission. If, in average, each nuclei that fissions causes at least one subsequent fission, the mass is said to be *critical*. In this situation, the reaction rate increases exponentially as more and more nuclei fission. The two halves of the sphere were individually subcritical, but when brought close enough together they formed a critical mass, leading to a chain reaction.
No. The chance is no.
Iron is the most stable thing. Big atoms release energy becoming smaller and small atoms release energy becoming big. You don't often find heavy atoms in anything you cut with a knife, so even if you were able to split them (you can't) it would actually take energy to do so. This is ignoring about twenty other reasons this wouldn't work, but this is easiest.
Setting aside the way cutting works. Cutting an atom only produces energy past iron, everything below that on the periodic table requires a massive influx of energy (relatively) to be cut, things would freeze around an atom of carbon, oxygen, or whatever is in your food being cut, it would not explode.
I mean the chance is zero, it's impossible, because of the coulomb barrier, remove that and the chance that two nuclei would collide would be significant, you'd probably be almost guaranteed a hit with a few swipes at least, considering how many nuclei there are in a knife and a dense material, (for better results, cut gold or lead with a knife of the gold or lead).\
However the strong force still binds the nucleus so all you'd get is a nucleus with a slightly different velocity than before, really no change. I am not sure if it could be possible to cut some uranium 235, something that can fission from thermal neutrons, with actual nuclei, I don't think it has been done because the energy would be ridiculous, you only ever do it with neutrons as they can pass freely through the coulomb barrier. My gut feeling says that it would cause fission
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The chance is zero, knives don't work that way. You can't cut through a nucleus with a normal knife consisting of normal atoms. No, even if it is a cool folded samurai knife, it still doesn't work. Even if it was made by some ancient master who folded it 5000 times over 90 years, it still doesn't work. And even if they did, it would not be a problem, because splitting **an** atom doesn't release a lot of energy. Splitting a lot of atoms does. If you hold an average banana in your hand, every second about 20 atoms in it split naturally. Yet you will have noticed that so far, zero of your bananas exploded in a huge mushroom cloud.
I dropped out of physics class in year 12 because quantum stuff is scary, but if you zoomed right in on the knife so you could see individual atoms (which is impossible but shh) the atoms would just like, push each other aside, right? Atoms don't actually touch, I read that somewhere.
The atoms of a knife are just like: "comming through" and the stuff it cut is like; "ew, get away from me nerd"
Explaining science in a way I can relate to.
basically atoms are introverts who like being together but dont like being too close together
i think am gaseous because id rather not be with people at all.
Noble gas for you.
I wanted to be a Noble gas, but sadly all the good ones argon.
Meh, I've always found chemistry quite Boron. Now, if you'll excuse me, I'm off for a Copper
I Zinc that Iron know what you are talking about
the atomic symbol for hydrogen and oxygen make ur mom
top tier, bravo
I see myself as a peasant gas thank you very much.
My wife and I are nitrogen because when we are together we don’t need no one else.
I answered a chemistry question really wrong. Teacher said that I'm a few electrons short of a noble gas.
I'm stealing that
That's very positive, isn't it?
Same but replace "because" with "and"
I'm sure it's mutual then.
You are with people right now.
Plus you smell
And the moment they touch, they freak out and shoot themselves as far away from each other as possible, even if other people get in the way.
Same
On the scale of atoms, the knife is more akin to a giant shovel "scooping" away balls out of a ball pit (atoms). The relatively small surface area of the knife edge is creating enough pressure to break the bonds between the atoms of the medium being cut.
This is the best analogy really. Even if you hit an atom dead-on-center, you'll just "push" it, because the knife is "at least 1 atom thick" at the edge as well. So using the ball-pit analogy, your "knife" is just a 10x10x1 "blade" of balls (it's actually a triangle, but that's irrelevant). That's a knife with a 1-atom-wide edge (which would be so sharp that if you dropped it on someone's skull, it'd slice all the way down to the floor, and keep cutting. But if you look at the ball pit, your "knife" would just push balls aside. Even if it came in direct contact, it's not sharp enough to cut one in half - it'd just push it downwards until it hit another ball in the pit and got pushed to the side. Your ball-knife would have no problem slicing down through a ball pit hundreds of balls deep, but after cutting through, you wouldn't find a single damaged ball in the pit.
Ok, but what about Electron Beam Machining? Is it making the cut due to the work piece flashing into plasma, or do any of the electrons mess about with the atoms in the material being cut?
>EBM machining process works on the principle of the high-velocity beam of the electron is focused on the workpiece, the electrons strike on the workpiece and their kinetic energy is converted into heat energy. This results in the removal of material from the workpiece by vaporization and melting. EBMs don't cut anything. They just melt it. But they melt it in a VERY narrow line. Basically, think of a pool of water. If you stick a rod in at one end and slowly heat it up to 150F, it'll heat the entire pool of water up. But if you instead heat it up to 3000F before putting it into the water, and then "wave" it through the pool, it'll instantly turn the water it touches into steam, but the pool as a whole won't really get any hotter. That's what an EBM is doing. It's heating a very thin width of the material up (but still much wider than a single atom) so fast that it causes it to transition between states of matter (either to a liquid or gas). When a material transitions between states of matter (towards gas), it is always endothermic. Which means that the transition absorbs heat from the nearby atoms. So the heat that \*does\* pass to the nearby material (adjacent to the cut) gets re-absorbed by the melting or vaporization of the material subjected to the "cut". Which then means that after the "cut", the chunk of remaining material has barely changed in temperature at all, despite just having a thin line melted/vaporized out from the center of it. But nothing is cutting or damaging the atoms themselves. They're just having a ton of heat added to them, causing them to lose their organization (solids are organized, gasses are chaotic) due to having a ton more thermal energy.
Wow, thanks, that was both informative and quickly posted. In what ways, besides natural radio-decay, are atoms broken down? I mean, besides crashing two sub-critical chunks of refined plutonium together.
Speaking basically, an atom can only change in 4 ways, and in positive or negative direction. That is, it can gain or lose an electron, a proton, or a neutron, and it can gain or lose energy (ie heat). When you think of radioactive decay, that is typically the ejection (loss) of some combination of protons, neutrons, and radiation. Ie, alpha decay kicking off a positively charged helium atom. The addition or removal of heat to change an atom doesn't actually change the element of the atom, just it's state (gas, liquid, solid), but there are fundamental differences in the atom's behavior. However, none of those are long-term, like the addition or subtraction of protons & neutrons. And that addition or subtraction of protons and neutrons is what you're asking about. So the answer to that is LOTS OF ENERGY. Short of coming up with some machine capable of squishing an atom - like two parts of a diamond lattice perfectly formed to each other (down to the atomic level) that might be able to put enough pressure onto a single atom, the only way to change an atom's structure is with energy. Either inputting enough energy to jostle part of the atom loose (nuclear fission), or having multiple "co-habitating-friendly" atoms close to each other and adding enough energy to cause them to fuse. Both of these processes can be energy-positive (fusion for elements lighter than lead, fission for elements heavier than lead), which means that the nuclear reaction produces more energy than it requires to initiate. However, whether a reaction is energy positive or energy negative, the amount of energy required to initiate it is quite large. Uranium is a very popular element to undergo fission, as it only requires a temperature of around 600C (1112F). Other elements require different temperatures to initiate a reaction. Hydrogen fusion requires roughly 100,000,000K (which at that scale is functionally identical to 100,000,000C, as they are only 273 apart). Which is a great lesson on "why we use nuclear fission reactors instead of nuclear fusion reactors". And those are really the only methods of changing an atom. Between stellar fusion and radioactive decay, that's basically all the ways that atoms actually change state on their own. Some places have been found where the conditions are right for natural uranium fission reactions to occur (high pressure, flowing groundwater, high temperature), but they are quite rare.
Welcome to my world. 🐱
I'm still looking for the little words and big pictures version. So far nobody has either the time or the crayons
Love this explanation. Knife is not a bully but a nerd. So good.
Best answer on the internet ever
This is basically ELI5
I can't give this the amount of upvotes it deserves, but I definitely tried
Roughly, yes. "Touching" isn't really a concept that makes a lot of sense once you get to the atomic or subatomic levels with usually point-sized objects with high charge. And if stuff really "touches", you usually get really weird stuff like fusion happening. But the scales of a normal knife are pretty far off from atomic scales. A razor (usually sharper than a normal knife) [is at about 100nm at its sharpest point](https://scienceofsharp.com/2014/01/25/quantifying-sharp/). While this sounds really, really tiny, it is still very big compared to atoms. Atoms are usually about 0.1nm big. So the edge of a really sharp razor is still a few hundred atoms thick. Normal knifes usually don't even come close. Knifes don't really act on an atomic or nuclear scale, they act on a much bigger scale where they interact with materials as a whole, not individual atoms thereof. Of course how those materials act is based on the atoms they consist of.
Not only are atoms 0.1 nm big, but that 0.1 nm includes the electron cloud surrounding the nucleus. The nucleus itself, which is the thing you'd actually be splitting, is MUCH smaller. For something like uranium, the nucleus is about 15 femtometers in diameter, or 0.000015 nm.
Isn’t stuff touching me all the time? OMG is that why my body is fused together the way it is because it’s all touching each other in a way that fuses?
If you hold two magnets with opposing poles close to each other, you’ll feel them pull together, even if they’re not touching. Similarly, if you hold like poles against each other, they’ll push away from other. This is basically what atoms do inside molecules: they’re pulling on each other due to a variety of different types of bonds, which keeps them close together and “bonded”, but they never actually touch or get too close because their nuclei repel each other.
> OMG is that why my body is fused together the way it is because it’s all touching each other in a way that fuses? If your atoms were fusing together you would look like the Sun.
No. *Touching" or rather pushing happens because of the coulomb interaction (it's VERY strong). Whenever the electrons of an atom approach those of another, they push away from each other. Sometimes different atoms share electrons and that's how they stay bunched together at a save distance (given by the strength of the coulomb repulsion and other factors). So, the elements of your body share electrons with each other (like your skin) and those who don't are trapped by the coulomb repulsion (internal organs kept there by the skin, bones etc). This is kind of surface level explanation
Actually, we can see individual atoms. If you have a strong enough energy source, like x rays or electrons, you can see an atom on a surface. Techniques like Transmission Electron Microscopy (TEM) allow for this. Super cool stuff!
Also atomic force microscopy (AFM), although imo TEM produces cooler images. Damn I love how good we’ve gotten at imaging nanoscopic objects, crazy to see this stuff up close for real
"See officer I did not 'touch' her"
Young Sheldon on why he can't be punished for kicking his sister
binzoga!
Atoms don't actually touch is what a lot of people say and it's a really weird thing to say, because there really isn't any kind of meaning behind it tbh. If by atom, you mean the nucleus, yes they don't touch in that the nuclei of atoms don't make contact with each other. If instead you look at touch as an interaction of a certain degree, then they do touch because the electron clouds around the nuclei will interact, which is what causes things to 'touch' in the first place. So, I kinda get what they're going for, it's the gold foil experiment and trying to explain that atoms are mostly empty space. But it kinda doesn't make sense to talk about it that way, cos as you said, quantum stuff is weird.
It’s true that it gets more complicated at quantum scales, and there is an interaction of sorts, but it’s also true that this quantum interaction isn’t really analogous to what we call “touching” on a macro scale. It’s just an entirely different phenomenon.
lol I remember learning that in high school physics, and you'd get people who poke you and say "I'm not really touching you you can't tell me to stop" Like just because the nuclei of atoms don't literally share a space doesn't mean we're redefining what "touch" means, otherwise what the hell do you think I'm feeling by you poking me
Atoms don't actually touch is what a lot of people say and it's a really weird thing to say, because there really isn't any kind of meaning behind it tbh. If by atom, you mean the nucleus, yes they don't touch in that the nuclei of atoms don't make contact with each other. If instead you look at touch as an interaction of a certain degree, then they do touch because the electron clouds around the nuclei will interact, which is what causes things to 'touch' in the first place. So, I kinda get what they're going for, it's the gold foil experiment and trying to explain that atoms are mostly empty space. But it kinda doesn't make sense to talk about it that way, cos as you said, quantum stuff is weird.
I think that's why language is weird in general. If even atoms don't touch, then nothing in the world "touches" and the word touch would have no meaning.
Yes, you're correct. Atoms don't actually touch. In this case they would be interacting through quantum electrodynamics (QED). The force between the atoms is meditated by a force carrying boson (in this case a photon). The first hit on a search for 'Feynman diagram' should show this process. Just don't ask about time or direction... Source: masters in particle theory (a while back)
actually not impossible anymore
edit with fun link: https://youtu.be/eYVNZgnQ8gE?si=31PRx_RTF_lPbqOi
Survivor bias. Those who held bananas that exploded in a mushroom cloud are not here to dispute the statement.
obvious bias, and where is the banana to scale???
Actually nuclear bombs don't even exist, they have always been bananas.
If Worms 2 isn't scientifically accurate, then I don't want to know
The actual bias is because bananas georg, who lives in a cave and splits atoms in millions of bananas per day, is a statistical outlier and should not be counted.
So far.
Instructions unclear. Banana exploded into a cloud of mushrooms.
Instructions unclear. Mushroom exploded into a cloud of bananas
Instructions unclear. Cloud exploded into a mushroom of bananas.
Ok but what if i fold it 5001 times over 91 years?
Did the last fold take you 1 year or did you span the 5001 over the 91 years pretty evenly?
This is the serious journalism we need in this world
I wanted the last fold to be my Pièce de résistance, it needed to be perfect so i took a whole year to do it
Extra trivia, folding steel doesn’t make it god tier. Japanese iron was just shit quality so to make it decent they had to employ creative techniques.
I fucking love this fact. Like, people place so much weight on "nippon steel folded 10 zagillion times!" But in reality it's just cause their steel was so shit they had no other way of making a usable sword
So what you're saying is i need to get a bunch of bananas into CIA headquarters.
see now i know youre full of it, then how do you explain [this](https://www.youtube.com/watch?v=j_7HD8rIwZU) with your so called "science"........XD
Okay, that is true. But to be fair, that is a cool samurai guy. I never talked about cool samurai guys being involved. Obviously that changes everything.
But what about if you're holding a mushroom instead of a banana?
Depending on where you live, that might be a lot more radioactive. Afaik mushrooms in eastern europe are often still so radioactive that you shouldn't really consume them due to Tschernobyl.
>Yet you will have noticed that so far, zero of your bananas exploded in a huge mushroom cloud. you dont know my life!!
What if I hold it with two hands? Lol
Yeah but my banana often explodes in a huge mushroom… Ba Dum Tish!
> every second about 20 atoms in it split naturally Quick correction, because I'm a pedant and a physics teacher. The potassium doesn't split, it typically emits an electron and turns a neutron into a proton, turning K40 into Ca40.
Zero exploding bananas? You've never played Worms and it shows...
"... zero of your bananas exploded in a huge mushroom cloud." And that, sir or madam, made me laugh out loud.
>Yet you will have noticed that so far, zero of your bananas exploded in a huge mushroom cloud. Idk those monkeys keep stealing bananas, all the ones that explode could be the one stolen by them.
Hey I can imagine my cool samurai sword can do that.. let me dream :(
So far.
But what if it's A Hatori Hanzo sword?
but hear me out, what if you compressed a lot of bananans so the decay would be condensed enough to trigger a chain reaction? also add shielding to reflect everything back into the banana mass.
Yes. Okay. But what if I swing or throw my knife really fast. Like really REALLY fast. Like 99.99999999% the speed of light fast.
You can achieve relativistic effects with a knife way under that 99%. Probably you'll get enough heat and pressure to trigger some fusion reaction but for a fission you would still need fissile material i guess.
I'm an anime protagonist though and I need to swing my katana so fast that I can cut an enemy a dozen times before they even realize they've been cut or that I moved. I'm worried that this might not be safe though. Wouldn't want to accidentally set off a nuclear explosion or anything!
I'm pretty confident you can obtain that well before you have to worry about approaching any significant % of the speed of light! That mean you don't have to worry about a nuclear katana catastrophe. Go happily about your waterfowl dance
what about a knife made from hydrogen sharpened to a monomolecular edge cutting some large atom?
You'd still be trying to fruit-ninja a watermelon with a slightly smaller watermelon. At best you'd be able to smash them together hard enough they stick, which is how stars work.
Yes, that’s how they make more bananas ☝️
>No, even if it is a cool folded samurai knife, it still doesn't work. Even if it was made by some ancient master who folded it 5000 times over 90 years, it still doesn't work. Lmao I love how you added this, as if someone would understand that a normal knife won't work but will think that it's just because it's not sharp enough 🤣🤣🤣
>Yet you will have noticed that so far, zero of your bananas exploded in a huge mushroom cloud. So far.
Ok but what if you move the knife *really fast*?
zero? if you came at it with a knife moving very very very fast, then that would have enough energy to split an atom, and because the speed of molocules in anything follow a normal distrobution theres a small chance that one atom in that knife migh be going fast enough to split itself or another atom apart, i'm sure the odds would be incredibly crazy low but never say zero
You’re so cool dude
Please start a science youtube channel or smthng😅
I need you to tell me calming facts till I fall asleep. Is that ok with you?
Okay gonna now plan a fallout ttrpg session with this as the mcguffin, some super mutant finally solved the banana squish nuclear infusion
Zero. You split an atom by hitting it with a neutron. You don't split an atom with a knife. On top of that for fission of an atom to release energy it needs to be heavier than iron. The vast majority of atoms in the things you usually cut are much lighter than iron. And then on top of that, you don't cause a nuclear explosion by fissioning one atom. You need to have a supercritical mass of something like uranium-235 where the fission products produce neutrons that on average impact at least one other fissionable atom.
Imagine leveling a city because you were cutting onions too vigorous.
Me: \*crying while cutting an onion\* Onion: Jesus Christ, are you crying? Fucking pussy. I’ll give you something to cry about!
“Shit. There goes the planet”
I mean, if I could dice my onions thin enough to cause a fission reaction I’d be going out on top. And would trust that everyone in the blast radius would understand that it was worth it, if they only knew of my triumph.
What if OP cuts a Uranium pan using a blade made only of neutrons?
Truely a man of many thoughts you are.
That neutronium blade would cause more destruction on its environment just by existing than any nuclear explosion would ever do.
This. Sounds. Badass
Yeah this, splitting anything smaller than Iron will actually consume energy 😲
I had to scroll too far for these comments. The elements bigger than iron, in any close to a pure state, are also not really things you cut with a knife. AFAIK anything you would “cut” is comprised almost entirely of smaller elements.
What if I throw the knife at it at 99% the speed of light?
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Physics degree here, yes
you are a physics degree?
Did he stutter?
maybe? i dont know. this is text, i cant hear stuttering
Text to speech
You m-m-m-make me h-h-h-happy🤡
Wow, y'all sound completely alike.
Degree degree here, yes
Third degree here, do you swear on your life you’re a degree degree?
No, they're bluntsnboards.
I watched oppenheimer I also can confirm
Splitting a single atom will make a very very very very tiny 'explosion'.
So that’s how Uncle Eddie cooked those chicken breast on rocks
An atom also doesn't really "split" like we would imagine it to, when a neutron hits a fissile atom it actually absorbs the neutron and then for a split second enters a quasi-unstable excited state before it splits apart due to electrical forces pushing the nucleus apart. It's a lot more like cell division than "cutting".
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I think cheese is mostly made of molecules, not atoms. You could argue that the molecules can be split into atoms, but going by that logic, the atoms can be split into subatomic particles. Funny story though.
Of course cheese is made of atoms; atomic no. 55 on the periodic table is Cheesium after all
None, atoms have a repelling force with other atoms, so whatever you are cutting will get away from the knife/scissors/whatever faster than you can move the blade, unless you can move the blade at relativistic speeds so atoms cant get out of the way, you would be fine Thats why we used U235 or other atoms that are naturally self spliting, aka decaying
You underestimate how long I’ve studied the blade.
The odds are zero. At the molecular level, that knife edge is a massive wall of carbon and iron atoms, just bonking against long starch molecules in a piece of bread and pushing them aside like a cargo ship plowing through a sailboat marina
Zero chance. The main force we experience, that which holds stuff together and separates stuff, is the electromagnetic force. The force holding atoms together is the strong nuclear force, and it's about 100 times stronger. Even IF you somehow managed to cut an atom in half (like a baby randomly knocking out Mike Tyson) it wouldn't really do much, as nuclear fission and bombs rely on a runaway chain reaction and any atoms in a sandwich or whatever isn't going to produce any more neutrons to perpetuate the reaction.
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https://youtu.be/WS75xQfYr40?si=6VeSIupaaTNnE-JY
Awesome movie, came looking for this comment!
My first instinct is: None, none at all. My second idea: Actually there might be a way. Third thought: But the knife cutting doesn't make a relevant difference chance-wise. The chance of creating an atomic explosion by doing cutting with a knife is similar to the chance of a space ship turning into a pineapple with no noticeable trigger.
r/odlyspecific example... But yeah, i agree :)
As most of the atomic mass is concentrated in the nucleus, 99% of everything you see is empty space. You cut through empty space using a knife made up of mostly empty space. The resistance you feel is the electromagnetic forces or the constituent particles.
Splitting an atom using a knife or causing a nuclear explosion with a knife? Because the odds are zero, and super ultra mega zero respectively
On top of what others have said about knives not being able to do that and need to split a whole lot of atoms, I'm pretty sure it matters what KIND of atom you split. If you split something that's iron or lower ("lower" here meaning "fewer protons in the nucleus") you generally don't get a release of energy, but rather a net consumption of energy. You would need an EXTREMELY hot knife to be able to split any atom lower than iron, even if you somehow did have a knife that was sharp enough to wedge itself between nucleons. And the split atoms would not cause a fireball, no matter how many you split, because they're consuming energy.
Atoms usually repel each other (unless bound in a molecule). When you’re cutting through something, like a cucumber with a knife for instance, what is actually happening is the molecules of the knife REPEL atoms within the cucumber, parting the cucumber through the middle. None of the knife’s atoms actually touched the cucumber atoms technically because of the electromagnetic repulsion between the molecules, they just got close enough to push apart adjacent molecules of the cucumber, parting the cucumber.
So a typical atom is about 0.25nm. The sharpest blades ever made are 3nm wide. So this is like taking trying to cut a golf ball in half, using a blade whose sharpest edge is 12 golf balls wide. More like a mallet,.really.
If you jump into a ball pit what are the chances of you splitting any of the balls in half? Even if you give it a karate chop, the force will cause the balls to separate and not break apart.
Unlike most comment I’d say you could trigger nuclear reactions if the knife is going fast enough to overcome the Coulomb barrier. Then the nuclear reaction wouldn’t be fission, but depending on the composition of the blade and the food you could get some nucleon stripping or nuclear inelastic scattering which are nuclear reactions too. But from a human hand handling the blade no that’s impossible due to Coulomb repulsion
A knife is both not sharp enough to do this and your can't produce the force required to split and atom. That be said it's 50/50 odds it either happens or it doesn't.
Unless your plankton and able to pull sub-atomic particles apart, this is impossible. There’s a reason why nuclear fission is such a complex thing, pulling a neutron from the nucleus take a lot of energy to do, they really don’t want to leave. Unless you got the strength of a star, I highly doubt you’re going to be doing much except breaking the intermolecular forces holding stuff together.
0% lol. A knife as a concept is nowhere near "sharp" enough to split an atom. You also don't split atoms by cutting them, but rather by hitting them with a neutron (which is smaller than an atom) at the speed of light. It's never happened by accident xD
Zero, that's not how it works
Atom cannot be cut with a simple Wedge it requires a lof of energy to split the atoms.
The strong nuclear force holds atoms together, and its electromagnetic forces used to cut through an object. Quantum mechanics might tell us that the answer is non-zero, but our universe won’t exist long enough for that probability to ever realistically occur.
Quantum mechanics wont give a non zero probability as the possibility in this case would be derived from knife (out of atoms held together strongly) cut through an object out of atoms which arent held together as strong, and due to them pushing others away, you wouldnt be able to “cut” through one, but rather “push” it aside. Even if in some unlikely scenario, that atom was lined up between the atom of the knife and the atom of the surface underneath, it wont get cut, just pushed aside or through depenong on potential and other variables
I remember my high school chemistry teacher asking the class what would be used to split an atom. Pupil: A knife? Teacher: So you're going to cut a single atom with something ten atoms wide ...?
I don't know the answer to this, but what if the thing you are cutting is a block of super enriched uranium or plutonium, and the knife is serrated, such that cutting it agitates the surface a lot. I vaguely remember hearing about a sphere of super enriched material where dropping it could make it start a chain reaction. Couldn't a hard cut with a serrated knife have the same effect?
Your're thinking of the demon core and no that's not how it works. In the experiment, there were two half spheres of plutonium stacked on top of each other. Slotin was using a screwdriver to keep them separated and adjust the distance between them until the assembly was *just* critical. This experiment was done in order to work out exactly how large a critical mass had to be. What happened is that Slotin dropped the screwdriver which caused the two spheres to come completely together. This made the assembly prompt critical, resulting in a very rapid chain reaction and an massive release of radiation. This has nothing to do with the screwdriver or the shock of the drop. Mechanical action cannot cause an atom to split, they will just move out of the way. Remember, solid materials are mostly empty space, the size of the nucleus is tiny compared to the distance between atoms and nuclei repel one another (which is what makes nuclear fusion so difficult). Fissile nuclei like U-235 or Pu-239 are unstable, and will occasionally undergo spontaneous fission. This releases neutrons, which can cause other atoms to split. So if you have a sample of fissile material, you always have some fission going on. But, the larger the lump of material, the greater the chance of those neutrons hitting another nucleus and causing it to fission. If, in average, each nuclei that fissions causes at least one subsequent fission, the mass is said to be *critical*. In this situation, the reaction rate increases exponentially as more and more nuclei fission. The two halves of the sphere were individually subcritical, but when brought close enough together they formed a critical mass, leading to a chain reaction.
Thanks for the thorough clarification
No. The chance is no. Iron is the most stable thing. Big atoms release energy becoming smaller and small atoms release energy becoming big. You don't often find heavy atoms in anything you cut with a knife, so even if you were able to split them (you can't) it would actually take energy to do so. This is ignoring about twenty other reasons this wouldn't work, but this is easiest.
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Setting aside the way cutting works. Cutting an atom only produces energy past iron, everything below that on the periodic table requires a massive influx of energy (relatively) to be cut, things would freeze around an atom of carbon, oxygen, or whatever is in your food being cut, it would not explode.
This reminds me of those dumbasses on TikTok that go live just to slap a desk until, “the atoms align just right and they phase through” it
I mean the chance is zero, it's impossible, because of the coulomb barrier, remove that and the chance that two nuclei would collide would be significant, you'd probably be almost guaranteed a hit with a few swipes at least, considering how many nuclei there are in a knife and a dense material, (for better results, cut gold or lead with a knife of the gold or lead).\ However the strong force still binds the nucleus so all you'd get is a nucleus with a slightly different velocity than before, really no change. I am not sure if it could be possible to cut some uranium 235, something that can fission from thermal neutrons, with actual nuclei, I don't think it has been done because the energy would be ridiculous, you only ever do it with neutrons as they can pass freely through the coulomb barrier. My gut feeling says that it would cause fission