One of the most trivial things that baffled scientists for decades
is how particle physics all comes together. Protons
have a +1 charge, neutrons have no charge, and electrons have a
-1 charge. Why is that. Well, the answer
to that and a lot more, came when they discovered quark.
Quarks are 6 of the 17 Fundemental particles
that make up the universe.
They have fractional electrical charges and are also fermions, meaning
they have a spin, or angular momentum of ½,
as opposed to bosons, which have a spin of 1.
They tend to stick together in groups, and certain recurring
groups have certain names, such as the neutron and the
proton.
The quarks in the neutron and the proton, namely the up
quark and down quark, do not decay, whereas all
the others decay into these 2 quarks.
Inside of the proton and neutron, you get
3 quarks. 2 up and 1 down
for the proton, and 2 down and 1 up for the neutron.
While the proton & neutron may have a size and mass,
quarks only have a mass. To get the size
of a proton and neutron, we have to look at the quarks movement.
They move nearly at the speed of light, but seem to
constantly bounce off a boundary which  is actually spherical,
and is exactly the size of a neutron and proton.
What is actually happening, is the strongest of the
fundamental forces, known as the strong nuclear force,
is forcing the quarks to be held in this spherical arrangement.
The ‘nuclear’ in the strong nuclear force, comes from nucleus.
The strong force also provides a charge to the quarks,
which physicists call colour.
This isn’t the same as what we would usually describe as color, but rather a
variant of charge, in terms of another
massless, fundamental particle, the gluon,
and it's interaction with quarks,
in a similar fashion to photons in the electro-magnetic spectrum.
The color, on the other hand, can be compared to that of electricity,
the only difference being, there are 3 variations of
charge (red blue green), rather than just 2.
The gluons are drawn like springs, because that is essentially how they
work. They pull quarks that exit the nucleon,
but barely affect the quarks already in it.
If scientists want to, they can apply a lot of energy, and
knock a quark out of the nucleon, and supersede the force
applied by the gluon. What you would expect at first,
is you would get a loose quark. But, this opposes what I said earlier,
where quarks like to stick together in groups.
So instead, what they do is
use this equation to convert the energy into a quark and
an antiquark.
This doesn’t break the law of conservation of energy,
as mass in a way is just a form of energy.
Overall, the interaction of quarks and gluons,
is what the field of quantum chromo-dynamics comprises of.
What is so interesting,
is this is often theoretical, and hasn’t been proven fully.
Instead, it just is a model for what we DO know, and how it all links up.
This means that there is still
a whole universe of knowledge, and possibilities to figure out,
and when we do, we will have resolved many unsolved mysteries.
