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How big is a Proton?

A Proton is 1.75 femtometre

What is a Proton?

“Have you ever wondered what makes up everything around us?” Well, the answer is in the tiniest particles that exist, and one of those is called a proton! Protons are incredibly small particles that are found in the nucleus, which is the very center of an atom. Every single thing you can touch, see, taste, and smell is made up of atoms, which means they are also made up of protons!

The Size of a Proton

You might be wondering, “How big is a proton?” Well, it’s so small that you can’t see it with your eyes, not even with a regular microscope! In fact, it’s one of the smallest things in the entire universe. The size of a proton is usually measured in a unit called femtometers, which is incredibly tiny. To give you an idea of how small that is, one meter is made up of 1,000,000,000,000,000 (one quadrillion) femtometers! The most common size of a proton is about 0.84 femtometers. That is so small that if a proton were the size of a marble, then an atom would be as big as a football stadium!

Size Comparison

To understand the size of a proton, let’s compare it to some things you might know.

  • If you have a piece of hair, it’s about 500,000 times thicker than a proton. That’s like comparing the size of a football field to a grain of sand!

  • A human cell, which is also very tiny, is still about 100,000 times larger than a proton. If a proton was the size of a marble, a human cell would be the size of a large van!

  • Even an atom, which is made up of protons, neutrons, and electrons, is much larger than a proton. An atom is about 100,000 times larger than a proton. If a proton was the size of a marble, an atom would be the size of a football stadium!

Interesting Facts about Protons

  • Protons are positively charged particles. This means they have a positive electric charge, which is what allows them to interact with other particles.
  • Along with neutrons, protons are often referred to as “nucleons” because they are found in the nucleus of an atom.
  • The number of protons in an atom determines what kind of element it is. For example, hydrogen has one proton, helium has two protons, and so on. This is why the number of protons in an atom is often called its “atomic number.”
  • Protons are incredibly stable particles. This means they don’t easily break apart or change into other particles. Remember, even though protons are incredibly tiny, they play a huge role in making up the world around us! So the next time you look around, remember that everything you see is made up of these incredibly tiny particles called protons!
Smaller By Category
Neutron
Neutrons are found within an atom's nucleus. They are thousands of times smaller than the atom itself. They have two down quarks and one up quark. Therefore, the neutron's charge is -1/3-1/3+2/3 = 0.
Lengths shorter than this are not confirmed.
All the objects that are smaller than this are unmeasured. The sizes that they appear are only estimates. Some things, like quantum foam, are just hypothesized. They aren't fact.
Range of the Weak Force
The weak force is one of the four fundamental forces of nature, and is the weaker of the two nuclear forces. As distance increases, its strength decreases. At just 10 attometers, the weak force is so weak it is unmeasurable.
Larger By Category
Helium Nucleus
The helium nucleus is thousands of times smaller than the atom, like a marble in a football field. The only reason matter feels solid is because atoms repel. If atoms didn't repel, everything would fall through each other!
Electron (Classical)
Electrons are so small that their size can't accurately be measured. The size of an electron varies greatly depending on how it's measured, whether it's based on the quantum model or, in this case, the classical model.
Chlorine Nucleus
A chlorine nucleus has 17 protons and anywhere from 11 to 34 neutrons. However, the majority of these isotopes will decay within minutes, if not seconds! The only stable isotopoes are chlorine-35 (18 neutrons) and chlorine-37 (20 neutrons). Even numbers of neutrons (especially magic numbers 2, 8, 20, 28, 50, 82, and 126) tend to be more stable than odd ones.