top of page

Quarks

Updated: Jun 23, 2020

By Oleksandr Koliakin


We know that the whole universe is made out of atoms. You are made out of atoms, the device you are using is made out of atoms and the Earth is made out of atoms. But what are atoms made out of?


People thought atoms were the most basic form of matter in the universe, until scientists discovered that atoms were made out of electrons orbiting a nucleus made out of protons and neutrons. But what are they made out of?


Electrons are a type of particles called leptons. For now, scientists believe that an electron is made out of... itself.


Protons and neutrons are a bit more interesting. Scientists thought they were the most fundamental particles, until they built giant structures called particle accelerators. These accelerators could accelerate particles such as protons and neutrons to enormous speeds. And then scientists realized, that if these particles were travelling fast enough, and they collided with each other, they would 'spill out their insides'. And this is how scientists discovered quarks.


Quarks usually never appear alone. They are held together in particles by other particles called gluons, which belong to a different type of fundamental particles, called bosons. There are six main types of quarks: The up quark, down quark, charm quark, strange quark, top quark and bottom quark.


Each quark has a different 'color' (in reality quarks don't actually 'have a color' since they are smaller than photons. However, scientists said that they have 'colors' to make it easier for other people to understand) and it doesn't matter what type of quark it is. The 'color' of a quark can be either red, blue or green. That means a top quark can have a color of either red, blue or green.


There are two ways quarks can be joined together to form more complex particles. If there are three quarks, and all of them have a different color, they could 'neutralize' each other to form a baryon. There are many types of baryons, and protons and neutrons are also baryons. We will talk about baryons in a different article.


If there is a quark and an antiquark, they could join together to form a meson, sort of like two opposite magnetic fields attract. However, mesons are usually unstable since the quark and the antiquark can annihilate to produce some photons. We will talk about mesons in a different article.


All quarks have a charge. However, it turns out that in order for physics to work, quarks must have a fractional charge. For example, the up quark has a charge of +2/3 and the down quark has a charge of -1/3. Therefore, you can guess that in a proton, there must be two up quarks and one down quark to produce a baryon with the charge of +1.


All fundamental particles, including quarks, also have an interesting property called spin. That basically means that particles spin. A particle can have a different spin. A particle with spin 1/2 has to turn around 2 times to look the same as it did before. Quarks only have fractional spins.


Complete the "quarks" quiz


Sources:

  • "A Brief History of Time" by S. Hawking

  • "SCIENCIA" (book)

Recent Posts

See All

By Oleksandr Koliakin Prefixes for measurements are incredibly important. Here are the basic ones (the ones in bold are the most common): x - any primary/basic unit (e.g. meters or seconds) p(x) = pic

bottom of page