 Alright, so there's a mole of atoms that's 6.022 x 10 to the 23 atoms in 12 grams of carbon 12, which is a small handful of soot. But just for the sake of it, how much room would a mole of something larger take up? Let's say a mole of peas. Okay, so I can approximate a pea as a sphere with a radius of roughly 3 millimeters. And I can use the formula for the volume of a sphere to calculate its volume. So the volume of one pea, volume equals 4 thirds pi r cubed. And the radius I've just said is 3 millimeters. So we'll have 4 thirds pi times 3 cubed, which is 27. And in total that gives me 113 millimeters cubed. Alright, so that's the volume of one pea. If I have a mole of peas, that's 6.022 x 10 to the 23 peas. So the combined volume of those peas will be 6.022 x 10 to the 23 x 113 millimeters cubed for each pea. And that gives me 6.81 times 10 to the 25 cubic millimeters. Now, I don't have a good feel for how big that is, because cubic millimeters are pretty small. And that's a really large number. And I can't see in my head how much room that takes up. So let's convert to cubic meters and see if that helps. So we'll write down what we know. And we're going to convert the millimeters cubed to meters cubed by converting millimeters to meters three times over. Okay, so that gives us 6.81 times 10 to the 16 cubic meters. Hmm, well that seems like quite a lot, but I still can't really imagine it. So the surface area of the earth is 5.1 x 10 to the 14 meters squared. So if I divide the volume of peas by the surface area of the earth, that'd be like spreading that whole volume of peas evenly over the surface of the earth. How thick would that layer be? So we can calculate that by dividing the volume of the peas by the surface area of the earth. And that gives me 134 meters. Now, just looking back over that calculation, my original radius value is only one significant figure. So I should round my final answer to one sig figure as well. So that gives me a neat 100 meters. Imagine the 100 meter straight on your local athletics track for a feel for how big that is. So we've worked out that a mole of peas would cover the entire planet to a depth of 100 meters. And I haven't even taken into account the fact that peas don't pack perfectly because they're spherical. So there would be extra space between them and that would make the layer even thicker. So can you see now that a mole is a very large number? And the point of it is for counting really, really tiny things. There's no point using it to skip count big things. Even an estimate of the number of stars in the entire universe only comes to about a tenth of a mole. To see another more detailed riff on this theme, see Randall Munro's excellent analysis of what would happen if you had a mole of moles. Just google a mole of moles to find it.