The Fundamentals, Part 3: The Strong Force

Part three is our first venture into relatively obscure physics. I’d reckon that not many people could accurately describe what either weak or strong forces do. Luckily, you won’t be one of those people. 

Years ago, when quantum science was first being explored, physicists started discovering a couple of very, very small pieces of matter and energy that made up everything, particles like protons, electrons, and neutrons. They called these the ‘elementary particles’ because of their special status as the building blocks of the universe. All of this progress led to more accurate models of the atom, and it was finally deduced that all atoms contained a nucleus in the center with a certain number of protons and neutrons, as well as an electron cloud surrounding this core. 

And for this, there was much rejoicing.

But how did the protons and neutrons stay together?




Neutrons are electrically neutral (hence the name), and protons are all positive; as we learned before, that kind of thing shouldn’t be possible, since all the positive charges would just push each other apart through the sheer force of electromagnetism. On the other hand, it couldn’t have been gravity, either, since that force only really has an effect on a grand scale. Hmm. Could it be a third fundamental interaction, perhaps? 

Well, that’s what scientists went with, despite having no physical cause decided on. This strange effect keeping the nucleus together was called the ‘strong force’, because it was over 100 times stronger than the electromagnetic force at such small scales, and over 1000000 times more influential than gravity. Several years went by until scientists realized its mysterious origin: quarks. It turns out that Physics had kind of jumped the gun when it came to that whole ‘elementary particle’ thing; protons and neutrons were not, in fact, the smallest particles in the universe, but were themselves made of even smaller particles called quarks. Each of these quarks shared another elementary particle between them, called a gluon. It was the gluon that created the strong force, and thus kept everything together in the nucleus of the atom. Science was saved. 

Check it: an electron and a positron meet, causing them to decompose
into two types of quarks and a gluon. Yeah, you actually know what all that means now. Cool.

And there you have it! I bet you never wondered why the nucleus, full of positive charge, never exploded apart under the pressure of its own electromagnetic force. It was the gluon all along. What a world...

Only one Fundamental Interaction left! Be excited. I know I am. 

Hint.