Atomic Theory

Hi, and welcome to Veritasium, an online science video blog. I'd like to take on scientific topics all the way from the simplest to the most complex.

So a good place to start, I think, is with a problem considered by the famous physicist Richard Feynmann. He asked, "If all the world's scientific information except for one sentence were destroyed in some cataclysmic event, which single statement would contain the most scientific information for future generations?"

His conclusion was that it is The Atomic Hypothesis. [Music] The atomic hypothesis states that all things are made up of atoms, tiny particles that are in perpetual motion; they attract each other when a little distance apart but repel if squeezed together. That statement is incredibly important to understand if you want to understand most of the rest of science, because everything is made of atoms, including you and me and the Opera House, and the Harbour Bridge, and the water, and the trees, and the grass, and the air and the clouds, and, well, you get the idea.

Everything is made out of atoms, so it's really important to understand the atomic concept if you're going to understand the rest of science. The idea that everything is made out of tiny particles has been around for thousands of years. The oldest recorded texts are in Greece and India.

In fact, the word atom comes from the Greek atomos, meaning literally, uncuttable. So the idea that they had was if you took a piece of matter, like this piece of aluminium foil, you could cut it in half and in half again each time reducing the number of atoms by half. But the idea was you could not go on doing that indefinitely, for there would come a point when you have only a single atom left and it is uncuttable; it's an atom.

How many times do you think I could cut this A4 sheet of aluminium in half before I reach a single atom?