 Hey everybody, Dr. O here. In this video we're going to talk about just how small atoms are and just how numerous they are. I love this picture here of the penny because it shows the world that we see and the world as it actually is, right? Everything is just made of atoms. Atoms are the basic unit of matter. So the typical size of an atom is going to be around 100 picometers, which is one 10 millionth of a millimeter. So obviously super, super tiny. Let's do a couple of size comparisons here. First of all, in the known universe, they're estimated to be at 10 to the 82nd atoms in the known observable universe. That's only what we can observe. Obviously, there's way more universe out there, so we have no idea what the actual number is. That would be, so 10 to the 82nd would be 100,000 quadrillion vaginitillion atoms. That's how many atoms are in the known observable universe. Other ones, just to give you some neat examples, I always tell students to take things with a grain of salt. A grain of salt would have 1.2 times 10 to the 18th atoms. That is a million, million, million atoms in a single grain of salt, a million, million, million being a quintillion. Another one I like to use, there are more atoms in a single cup of water than there are cups of water in all the oceans on the planet. And then of course, let's talk about humans. This is a human anatomy and physiology course. If you take a typical 154-pound human, there would be 10 to the 27th atoms. That is 7 billion, billion, billion atoms in your human body, so 10 to the 27th. So that shows how many of their atoms there are in things. How do we cram so many atoms in such a small space? It's because they're super tiny, like I said before. Look at the picture up here. If you took that football stadium, and the entire football stadium was a single atom. The nucleus would be a marble sitting on the 50-yard line. So that just says most of the space in an atom is actually in the electron cloud. The nucleus itself is super, super tiny. Then you look at the blueberries here. If you took the number of atoms in a grapefruit, I don't know why they use these examples, but they're good ones, the number of atoms in a single grapefruit, take the entire sphere of the earth and fill it with blueberries. That's how many blueberries would fit into the earth. That's how many atoms there are in a single grapefruit. So atoms are super, super tiny. We'll also talk about how extremely valuable and useful they are. We wouldn't be here talking if it wasn't for them. So I hope this helps. Have a wonderful day. Be blessed.