What is a Proton? - Simple Science
Welcome to Quatr.us Study Guides!

What is a Proton?

May 2016 - A proton is a tiny particle, smaller than an atom. Protons are too small to see, even with an electron microscope, but we know they must be there because that's the only way we can explain how atoms behave. To give you an idea how small a proton is, if an atom was the size of a football stadium, then a proton would still be smaller than a marble.

Pretty much all of the protons in the universe probably got made very soon after the Big Bang. At first there was no stuff, just a lot of loose energy shooting around everywhere in the form of photons (light) and larger particles like photons called bosons. These early bosons had tons of energy and a lot of them broke apart into protons and anti-protons. Most of these protons and anti-protons eventually lost energy and hooked back up into bosons again, but some of the anti-protons seem to have gotten lost somewhere, and all the mass in the Universe comes from these left-over protons.

All protons, everywhere in the universe, are exactly the same, and pretty much all of them are inside atoms. Different atoms have different numbers of protons; what makes an atom be a helium atom, or a gold atom, or an oxygen atom depends on how many protons it has, not what kind they are.

Protons make the nucleus, or center, of an atom. The simplest atoms - hydrogen atoms - have a nucleus made of just one proton. But most atoms have more than one proton, and at least one neutron to go with each proton (some have more than one).

Protons are actually made of even smaller invisible particles, called quarks. Each proton has three quarks, two up quarks and one down quark. A strong nuclear force sticks the quarks together. Most of the mass of a proton comes from this strong nuclear force, rather than from the quarks.

Because a proton has two up quarks and only one down quark, it has a positive charge, like the positive end of a magnet. Two things that have positive charges push away from each other, so the protons in an atom are always pushing away from each other. They need the neutrons to pull them together. The neutrons help to stick the protons together, using the strong nuclear force. The heaviest atom that exists in nature is uranium, with 92 protons. Even the neutrons and the strong nuclear force can't hold together more protons than that for more than a few seconds.

Learn by doing: a project with magnets
More about neutrons

Bibliography and further reading:

Neutrons
Electrons
Atoms
Chemistry
Quatr.us home


LIMITED TIME OFFER FOR TEACHERS: Using this article with your class? Show us your class page where you're using this article, and we'll send you a free subscription so all your students can use Quatr.us Study Guides with no distractions! (Not a teacher? Paid subscriptions are also available for just $16/year!)
Please help other teachers and students find us: link to this page from your class page.
Karen Carr is Associate Professor Emerita, Department of History, Portland State University. She holds a doctorate in Classical Art and Archaeology from the University of Michigan. Follow her on Instagram or Twitter, or buy her book, Vandals to Visigoths.
Cite this page
  • Author: K.E. Carr
  • Title:
  • Site Name: Quatr.us Study Guides
  • Publisher: Quatr.us
  • Date Published:
Proud of your class page, homework page, or resource page? Send it in and win a Quatr.us "Great Page!" award!
Sign up for more free articles and special offers in Quatr.us' weekly newsletter:
We will never share your e-mail address unless you allow us to do so. View our privacy policy. Easy unsubscribe links are provided in every email.
Comment on This Article

Does your class page honor diversity, celebrate feminism, and support people of color, LBGTQ people, and people with disabilities? Let us know, and we'll send you a Diversity Banner you can proudly display!
Looking for more?
Quatr.us is loading comments...
(Comments will appear after moderation, if they are kind and helpful. Feel free to ask questions, and we'll try to answer them.)
Cite this page
  • Carr, K.E. . Quatr.us Study Guides, . Web. 25 March, 2017
ADVERTISEMENT