Why does splitting an atom create energy? And why is it so much energy?
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Second part: It’s not just one atom. Splitting one atom releases a lot of energy *for one atom*, but it’s still a relatively atom-sized amount of energy. A nuclear reactor has to split lots and lots and lots of atoms to get the energy out, just like a car burns lots and lots and lots of molecules of gasoline.
Basically, for very advanced physical chemistry/physics reasons, every atom’s nucleus wants to be iron. Iron is like the bottom of a valley – going either way (adding or subtracting protons and neutrons) takes energy. So if an atom is smaller than iron, it wants to fuse to become iron. If an atom is larger than iron, it wants to split to become iron. Just like rolling a ball downhill, moving closer to iron releases energy.
Why so much energy? Well, as another commenter said – the strong nuclear force, the one that holds nuclei together – is veeeeery strong.
The mass of the starting atom is more than the mass of the resulting atoms. The missing mass is released as energy. We know from Einstiens famous equation that
> energy = mass x c^2
c is already quite a large number (3×10^8) so c^2 is much larger, 9×10^16. Loosing a small amount of mass creates a large amount of energy.
Finally, I’ll point out that this works the other way round with small atoms, if you take 2 small atoms and manage to stick them together, you’ll also lose mass and release energy. The changeover point happens at iron.
Stuff as we understand it , the chair you are sitting in for example or any physical object is made of energy at its most basic level.
Energy is squashed together and held in place by bonds and that is an atom.
If the bonds are somehow broken then like a balloon popping all that squashed up energy is released.
In a chain reaction like in an atomic bomb, when the first atoms are split and the energy is released , bits fly out and strike nearby atoms and split them. Those atoms release energy and split more nearby atoms and like a spreading fire , one match can start a fire that burns down a building .
TL;DR Some folks think ‘matter’ is large amounts of energy held in a kind of self sustaining containment field with bonds kind of like magnets but not magnets really.
Atoms are made up of Protons, Neutrons and electrons. We can individually ‘weigh’ protons and neutrons to work out their mass (electrons are very low mass, so lets ignore them)
if you jam a bunch of protons and neutrons together to form an atom (lets say uranium 235, that has 92 protons and 143 neutrons, so a big heavy atom)
What should the atom weigh? 92 x proton weight + 143 x neutron weight right? its what you would expect, but it doesn’t, it weights less than this.
This mass difference is made up of the ‘nuclear binding energy’ (yeh, mass converting to energy and back, there is complicated science here too)
So now we crack that atom like a walnut, into two smaller atoms. Now weigh these, surely the total mass will be same the same as the original right? you would think, but the total mass is now a little Higher.
This is now where E=MC squared comes in (its actually change in energy = change in mass times the square of the speed of light) and because of the change in mass, there is a change of energy, and the excess energy gets released as heat/motion, usually through the reaction kicking out a seriously fast moving neutron or similar.
when an atom splits, it blows off its electrons. so the two resulting atoms have a high positive charge and kind of act like a magnet. they will collect electrons from all around causing friction. and friction = heat and heat = energy
Einstein realised that matter and energy are the same thing. A little bit of matter is the same as a lot of energy. When you split an atom, the two parts it splits into are slightly less than the whole you started with. The difference is released as a lot of energy.
Particles which makes an atom have small range strong force that binds them together, and longer range weaker repelling force. So, this makes two ways to make energy of atom: 1).You either take an atom big to the point of small range force not spreading enough, you bombard it with neutrons and it splits, releasing more high velocity neutrons and recombining into more stable smaller atom, this leads to chain reaction with stable heat output or explosion(nuclear reactors and fission nuclear bombs). 2). You take small atoms containing extra neutron, heat them to the point of them crashing into each other so violently, that they break through the weak long range repelling force and get glued together by strong low range force. This creates tremendous (even compared to fore mentioned fission reaction) amount of energy, but the tricky part is getting to that temperature. It is achieved through separate fission reaction in thermonuclear bombs(like in tsar-bomb), high gravity fields(like inside stars), and fusion reactors for stable output are still being theoritised. Hopefully we can harness thermonuclear energy in safe way before the turn of the next century.
But if you are just curious, where that energy comes from, then the answer is mass. Standalone parts of atoms weight more than combined atom. Not by much, but since E=mc2, even miniscule amount of mass holds incredible amounts of energy.
It takes a lot of energy to bind subatomic particles together to form an atom. When an atom becomes unstable, it can “split” into two smaller atoms. The subatomic particles separate to form two smaller atoms, but there’s some of that binding energy left over. That’s what gets released, and it’s very strong. Do this millions of times and ka-boom.
the answer is to do with einstein’s famous E=MC² equation. Energy = mass multiplied by the speed of light squared. The speed of light is a big number, so if you square it you get a damned big number.
When you split an atom into two smaller different atoms, the results weigh less than the original. the weight(mass) lost is converted into energy. Stunning loads of energy!
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