How Were Atoms Discovered?

Welcome to my fourth “Science Answers” post! If you have a question, you can ask it in the comments here, or ask it in an email. Or find me on Facebook!

Q: (1) How did scientists find elements in the first place? Could there be more undiscovered elements?
(2) How did scientists create the periodic table?
(3) How do we know that everything is made up of atoms, when atoms are so small that they can’t even reflect light (a necessity for seeing them)?
(asked by Mukesh Garbyal)

Really good questions! I was asked these in a comment on my post “Types of Atoms,” and chose to answer them in a post of their own.

Let’s take this apart. I actually want to address the third part of the question first, since it contains a misconception: atoms can reflect light. Their interaction with light is actually why we can see anything in the world.


Continue reading

The Building Blocks of the Universe


“The Building Blocks of the Universe.” When you put it that way, atoms sound less like a topic specifically for a chemistry class and more like something astronomers might discuss.

They really are. I’ve got a fantastic reason to include atoms under astronomy, and its name is stellar spectra.

We’ve encountered stellar spectra before in these astronomy posts. When I wrote about the spectrograph, an instrument astronomers use to study data, I talked about spectral lines. I also promised we’d come back to elaborate on that later.

We’re not actually going to talk about the spectrograph in this post. I’m saving that for another time. For now, I’m going to cover atoms in a little more detail.

That way, we’ll have a better understanding of how they interact with light later on—and that will help us understand the spectrograph. Continue reading