Chemistry Lesson #5 – Subatomic Particles (Part 2) – Particle Sizes

A Single Atom

A Single Atom

Now that we have talked about a few ways in which we all interact with subatomic particles on daily basis, let’s talk a little more about the properties of these tiny little guys! If we can understand the properties of subatomic particles, and we know that subatomic particles combine to make atoms, then we can explain many properties of the atom, by using the properties of the subatomic particles. And you should be comforted by the fact that there are only a few properties that are actually important to us (unless you’re a particle physicist)!

Those properties are size, mass and charge. Let’s focus on the size for now. The size is difficult to comprehend because subatomic particles are so incredibly small that we can only explain them by using analogy.

Here’s an example.

It would take just under half a million pennies to fill an average size American house and there are around 132 million homes in the U.S. (according to the 2010 Census). This mean it would take 54 million billion pennies to fill every house in the U.S.! Let’s compare this to the number of protons you could pack into an object the size of a marble.

You would have to pack every house in the U.S. with pennies, and then repeat this over a trillion billion times (which is a number a million times greater than the amount of pennies it would take to fill every house in the U.S.), just to come close to the number of protons you could pack into an object the size of a marble! Stop and think about that for a minute; it’s hard to even grasp!

Thankfully, there is no major difference between the size of a proton and a neutron, therefore most scientists just assume they are equal in size for all practical purposes (and mass is also assumed equal which I will explain later). This simplifies things! But how about the size difference between a proton and an electron?

Well, we know that the electron is much smaller than the proton, however, there is a fascinating problem with even asking this question! The question assumes that an electron is a particle – or more sufficiently, a small “physical” object that takes up space. In reality, an electron does sometimes “behave” like a particle, but it also “behaves” like it’s not a particle. I don’t want to confuse you, but let that just be a taste to pique your curiosity for a later post about the nature of the electron. These things are crazy!

For the sake of this analogy, let us assume that an electron is currently “behaving” like a particle. In this case, the size difference between an electron and a proton is like the size difference between a small bee bee or pellet (from a bee bee or pellet gun) and a bowling ball. The proton is somewhere around two thousand times larger than the electron, just as the bowling ball is somewhere around two thousand times larger than the bee bee.

At least you can comprehend this number! And since we are left agreeable, I will end it here!

3 thoughts on “Chemistry Lesson #5 – Subatomic Particles (Part 2) – Particle Sizes

  1. I love the use of analogies! It’s crazy to think of tiny things actually are and nothing does a better job of helping you get that perspective than a good analogy. You used one for the way electrons behave as a particles, how would you describe the way electrons behave as non-particles?

    • Nathan, I want to do this question justice. I have a couple more lessons to write and post and then I will do one on the incredible personality of the electron. It’s fascinating stuff!

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