Every source is way too complicated for me to understand how the residual strong force works (nuclear strong force) and along with that how come binding energy contribute
In: Physics
It’s similar to forces between neutral atoms where it’s somewhat easier to explain. Imagine you have two atoms (left, right) where each atom has a positive and a negative electric charge in it and some random orientation:
+ + –
–
The positive charges repel each other, the negative charges repel each other, but pairs of positive and negative charges attract each other. That makes them rotate that way:
+ –
– +
Now the attractive pairs have a slightly shorter distance than the repulsive pairs. Shorter distance means stronger force. That makes both atoms attract each other.
For the strong interaction you have something similar. Protons and neutrons are made out of quarks which have a “color charge” and different charges attract each other.
If you have a free proton and a free neutron then they attract each other via this process. They can collide and form deuterium. The energy of the collision is released, in this case as radiation. Most nuclear interactions are more complicated but the general idea is the same. You look at how much everything attracts each other and how much energy the nucleus has overall. In addition to the strong interaction you also need to consider that all the protons repel each other. If the overall energy decreases in a reaction then the difference is set free – as radiation or as fast-moving particles flying away.
For very heavy nuclei you have tons of protons all repelling each other, so splitting the nucleus and letting half the protons fly away from the other half releases energy, a little bit like expanding a spring can accelerate a mass that is being pushed away.
Residual strong force / nuclear force just refers to the force which holds the nucleus together. They stick together and don’t typically break apart so there must be a force doing that. We know that a force must be doing it because protons have positive charge, and like charges repel each other, so how a nucleus made of two protons, a.k.a. a helium atom, exist? They can exist because the residual strong force holds the nucleus together
The strong force has charges, just like electromagnetism. And just like electromagnetism, charges attract together to form a “neutral” structure.
One of the main differences is that the strong force has three charges instead of two, and their behaviour is far more complex.
Also unlike photons in electromagnetism, gluons (the force particles) actually carry a charge themselves, which means they interact with eachother. That both changes the behaviour of the force (why it has such a short range) and means there’s a lot of energy bound up between quarks.
As for how does binding energy generate mass… Well, it just does, ALL “confined” energy does. That’s from General Relativity, E = mc^2
Chemical bonds (electromagnetism) have mass too. Hell, a compressed spring technically has more mass, even though measuring that is tricky.
As for generating energy in nuclear reactions, it depends if you mean fusion or fission, since they’re opposite. In fusion, two nuclei have more energy separately than together, so when they fuse, they release the difference. In fission, the nucleus has more energy than the results of a split, so when ot does split, the difference is released.
The difference itself comes from the fact that the more protons you have in a nucleus, the more electromagnetic repulsion you have, but being bound by the Strong force is more energetically favourable than not. So in small nuclei, the Strong binding outweighs Electromagnetic repulsion, but in large nuclei it’s the opposite.
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