how the nucleus of an atom is actually split to create an atomic bomb?
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A bunch of conventional explosives are set off which push unstable isotopes together very tightly.
Some of those are always breaking down and shooting off a bunch of neutrons. So when you compress them down very tightly, it becomes certain that some of those neutrons will hit other nuclei, which will cause them to break apart. And also produce tons of flying neutrons. These then hit other nuclei and a chain reaction very quickly goes off
Atoms are made of electrons, neutrons and protons. Protons have the same electrical charge, so they naturally want to repel each other. To keep them together as atoms there is something called the strong nuclear force binding the protons and neutrons together in the nucleus.
Einstein said that mass and energy are the same thing in different forms, and described that by the famous equation of E=MC^2. A little bit of mass times the speed of light squared is equal to a lot of energy.
That binding energy of the strong nuclear force thus adds to the mass of the atom. Very large atoms, such as uranium, have a lot of binding energy since they are made of lots of protons and neutrons.
If you send a fast neutron into the center of a uranium atom, it’s going to knock the nucleus apart like a cue ball hitting a rack of pool balls. In doing so, new, smaller atoms are formed using the same amount of protons and neutrons, as well as a few extra free neutrons that will break open more uranium atoms before they decay into a proton and an electron themselves.
However, the total binding energy for those three new atoms is going to be less than the binding energy needed for the original uranium atom, so there is some excess energy left over. As more and more uranium atoms break apart, more and more free binding energy is released. That’s the power of the nuclear reaction.
What you’re talking about is a fission bomb, specifically. This usually involves packing together a large amount of unstable, radioactive material, then using a detonator to launch particles that have some small chance of colliding with the nucleus of these unstable atoms. This causes them to split, send out particles of their own, which again have a small chance of colliding with other unstable atoms and repeating this chain reaction.
If you have enough material close enough together (and unstable enough), this chain ramps up more than it slows down, releasing a *huge* amount of energy in a very short period of time even if only a small amount of the fuel is “used” in this way.
There are two primary forces at work in a nucleus; electromagnetic force and strong nuclear force. Gravity is too weak to matter at such a scale and the weak force is too complicated for me to talk about, although admittedly it is important.
The strong nuclear force actually holds the nucleus together, with protons and neutrons exchanging virtual mesons (quark-antiquark pairs) in order to stick together. The positive charge of the protons, however, introduces a pressure trying to drive the nucleus apart, though this doesn’t typically matter as the strong force is MUCH stronger (hence the name). However, the EM force maintains its strength over significantly larger distances than the strong force, and this adds up the larger the atoms get.
Uranium (the heaviest of the naturally occurring elements) and plutonium (a manmade element just above uranium) are big enough that when we compress them like springs, the EM force overpowers the strong force and the nucleus breaks like a rubber band ball. Particles ejected from this reaction will crash into other radioactive particles nearby causing a chain reaction.
There’s a lot of refinement to ensure you have enough of the unstable particles, but once you have that enriched product, it’s really down to compressing it. Some designs have a lump of material being shot like a gun into a bigger lump. A better design was a shell of conventional explosives around a radioactive core. We’ve since moved on to thermonuclear weaponry, which uses the fission reaction to trigger a fusion reaction for an even more energetic explosion.
Scary thing is, we can keep stacking them almost indefinitely; fission triggers fusion bomb to trigger bigger fission reaction to trigger bigger fusion reaction and so on.
There’s two types, broadly speaking, of atomic bombs; those that use fission (splitting atoms) and those that use fusion (combining atoms). All modern atomic bombs use fusion, but you’re asking about fission, which was used in the bombs dropped by the USA during WWII.
Radioactive materials like uranium and plutonium are constantly going through what’s called spontaneous fission. These elements (particularly versions with extra neutrons attached) are really unstable and prone to just falling apart, turning one atom into two and kicking off 2 or 3 neutrons in the process.
Those neutrons can hit *other* uranium or plutonium atoms, turning them into an extra-neutron extra-unstable version and causing them to split, releasing 2 or 3 *more* neutrons.
If you have a certain amount of the radioactive element in a close enough space, you’ve achieved what’s called *criticality* where enough neutrons hit other atoms to keep the chain reaction going, and in fact *increasing* in rate until all the radioactive atoms are split. This out-of-control chain reaction generates a huge amount of heat and explosive force – i.e. it is a bomb.
Early fission bombs basically had two pieces of uranium in them. Each piece was small enough that it was not critical. They were slowly decaying, but each decay didn’t manage to trigger 2 new decays so the reaction didn’t spiral out of control.
Once the bomb hit the ground, a conventional explosion would force the two chunks of uranium together, forming a combined mass that *was* critical. A chain reaction very quickly took place, splitting all those atoms and releasing tremendous amounts of heat.
Later designs would use a *single* piece of radioactive material, then squish it from all directions with explosions around it. By squishing it inwards it was made more dense, and thus critical.
Other designs involve shooting neutrons at the radioactive material to trigger the reaction. And again, this does not cover *fusion* bombs, which were first constructed in the 1950s and are likely the only type constructed today.
Atoms have an incredible amount of stored energy. Energy is not created or destroyed, so if you destroy an atom, that energy is carried out word, which affects the atoms surrounding it. This explains the chain reaction. Put forth enough energy to break 1 atom and the rest will go down. Also, atoms absolutely do not like “touching” eachother. If you can push atoms together enough, the chances of electrons bumping into eachother is increased. Electrons HATE eachother and will not greet eachother quietly.
Oversimplified version:
When a neutron hits uranium very quickly, the atom will get separated into smaller atoms, with some more energy released as neutrons. All of these neutrons then go on to do the same with other atoms, releasing many neutrons, until eventually you have an extremely high amount of energy.
Imagine having a giant pile of slightly sticky/magnetic marbles.
Imagine throwing another marble at the pile, very fast. What happens?
The pile will break apart, scattering. A few marbles will end up shooting off on their own, and then you’ll get a few smaller piles of marbles.
The marbles are “happier” in smaller piles because while each marble wants to be close to other marbles, they also want to be close to the floor (because gravity). And if you have two smaller piles, the average marble will be closer to the floor than if you had one big pile.
In energy terms, this means the marbles have less energy, on average, in the smaller piles than they did in the big pile.
If the new state has less energy, that energy must have come out somewhere; and it will have come out in the energy of those few marbles that went shooting off, along with a bunch of noise and heat from all the marbles crashing down.
A nuclear *fission* bomb works this way. You take a large, unstable nucleus (uranium, plutonium – something like that), you smash it with something, and it breaks apart into a bunch of smaller nuclei. You get a few random neutrons flung out … which then hit the neighbouring nuclei, breaking them apart. Which throw out more neutrons, hitting more nuclei and so on – a chain reaction, that goes “supercritical” and increases until you run out of big nuclei. The equivalent of all the “noise and heat” from above is what causes the explosion; there is a little bit of extra energy that comes out in the form of photons – bundles of energy – which smash into everything anywhere near the bomb. And you get an explosion. You don’t get a huge amount of energy from each individual nucleus, but you have a whole load of nuclei.
Nuclear *fusion* bombs work slightly differently. With fusion it is more like taking a few of these magnetic marbles, holding them near each other, and letting them smash into each other. You get a bunch of energy out (the noise and heat from the smash), and that is where the explosion comes from.
We take advantage of the fact that radioactive isotopes are relatively unstable. Then we fire neutrons and hope it hits a nucleus. When it does, it changes the configuration of the nucleus, making it more unstable, which causes the atom to split. I think.
throw a neutron at it real hard
when the nucleus is hit, it asplode and throws more neutrons real hard at other atoms
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