how can splitting a tiny piece of an even tinier atom create such a vast explosion?
In: Physics
The nuclear bombs dropped at Nagasaki and Hiroshima – the material that blew up was the size of a peppercorn. About 2 grams.
Almost all of the remainder of the nuclear material was blown out with the explosion of that 2 grams, and never did anything.
Interlock your fingers together and don’t let go. Try to pull your hands apart. Your grip is likely stronger then your ability to pull your hands apart. Now imaging Dwayne the Rock Johnson walks up and pulls your hands apart. He’s pulling and pulling and your grip is strong, but you can feel your fingers weaken. Suddenly your fingers lose grip and your hands fly apart in a burst of energy.
That’s what happens when you split an atom. Energy used to keep bits together is released. Except the energy released is enough to release more bits. And in an instant, protons are flying in all directions releasing ever more energy until they run out of other protons to hit.
because even tinier little bits got turned completely into energy. Kind of like how a little bit of your eraser rips off, but instead of balling up it’s blasting through solid surfaces.
But there are no tiny pieces of atoms that are paradoxically bigger than the atom itself.
A single atom? The energy is tiny. But way more than combining a pair of hydrogens with an oxygen one for example.
A uranium rod has many atoms, many of which are splitting all the time.
Depending on how close your splitting atom is to others it might only make a Lil heat, or hitting another atom will destabilise it enough to split it.
In a power station you balance this for a steady elevated rate. In a bomb you aim to split as many as you can in a fraction of a second
Imagine there’s layers like an onion to get to the middle of the tiniest weapon of mass destruction. Ones you get to the core, there’s only one layer left until it explodes. By leaving the forbidden grape alone, we can avoid massove boom-booms.
Follow-up question: how do you actually break atom bonds?
Eli5:. Think of an atom like a classic mousetrap.
The arm that you press down and latch is analogous to creating the atom in the first place.
The “arm” is stiff and resists you pressing it to the base. You have to apply a large, constant force to press it into place.
This happens in atoms because protons really push hard away from other protons (like electrical charges repel). But with enough force from outside, you can squeeze then together. This force for atoms comes from the intense heat and pressure found in the coe of stars, or during supernovas.
Once the arm is down, there is a latch that holds it in place. This latch is very short range, it only works once you get the arm very close to the base. This latch is also much stronger than the arm, since it holds it in place.
In an atom, this is the role of the strong nuclear force. It is an incredibly strong, but very short range force. If the protons are pushed into the region where it is stronger than the electric force, they will snap together, despite the protons pushing apart.
For fusion energy, stars push together small atoms, like hydrogen and helium. When the string force takes over, there is plenty of room left for them to move when they snap together. This means the atom sorta “jumps” when they collide. This can bump nearby atoms and transfer the energy away as heat.
For atoms larger than iron, there really isn’t enough space for then to snap together. It’s more like you’re trying to cram more and more stuff under the latch that is the strong force.
If you smack the latch of a mouse trap, then the spring arm flies free. Same with an atom that experiences fission. If you smack a large atom a part might fly free, propelled by the protons hating other protons, and the rest of the atom crunching closer under the strength of the strong force.
Something that I think is not emphasized enough on other replies is that in the explosion of an atomic bomb you are involving millions of millions of millions of millions of atoms (around 6^24 ). This is an incomprehensibly big number.
To add on to the other comments, it’s also *hard* to get that explosion. If atoms are releasing a ton of energy, the atoms near them tend to be blown away from each other. That makes them too far apart to actually slam into each other in order to get them to split. As a result, you have to have a *massive* system in place to try and prevent that as long as possible. The Fat Man bomb had 6.2kg of plutonium, surrounded by over 4500kg of high explosives and a few other tricks in order to crush the plutonium atoms together long enough for them to split. It successfully kept the plutonium atoms close enough together for long enough that enough that about 1kg of the 6.2kg in the bomb actually split. To give a sense of scale here, solids are effectively uncompressable in everyday experience, but in this case a roughly soda can-sized chunk of plutonium was crushed down to the size of a chicken egg for a duration of a few microseconds. For a bomb like Fat Man, even a slight error in the timing of the explosives for compression, microseconds or fractions of microseconds, can result in the high explosives trying to crunch the plutonium having a bigger boom than the plutonium itself does. It requires *incredibly* precise conditions.
To give another sense of scale here, it’s not just a few atoms splitting. If I did my decimals correctly, in the Fat Man bomb, it was about as many plutonium atoms as there are stars in the observable universe, or the number of grains of sand on 1000 copies of earth, that all split in a few microseconds.
Modern fission weapons use various methods so that they can get by with a much smaller amount of explosives around it, but the principle is the same.
It doesn’t. The explosion happens when you split lots and lots and lots of atoms at the same time. Just like a gasoline fire means lots and lots and lots of molecules have to burn. But you still get way more energy per atom than you get with burning.
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