0

In our topic regarding density, a calculation was shown where the mass of one teaspoonful of nuclei was equal to the mass of all the people on the Earth. I understood the calculation, but couldn't understand why it is so. It just doesn't make sense!

Cross
  • 3,310
Amanat Aziz Khan
  • 11

2 Answers2

3

It's because there is so much empty space in an atom. The nucleus of each atom occupies only a tiny fraction of the volume of the atom.

So if they could all be next to each other, the nuclei of all the atoms of all the people on earth, would fit into a small volume.

John Hunter
  • 13,700
  • Some people would argue that the space between nucleii in ordinary solid matter is not empty: It's full of electrons. – Solomon Slow Sep 11 '21 at 13:46
  • 1
    @SolomonSlow But that space between nuclei is not entirely filled with electrons. It is just the space that electrons can occupy. And the mass of the electron is much smaller (about 1/1837 of the neutron). – Mechanic Sep 11 '21 at 14:27
  • @Mechanic7, Re, "...just the space that electrons can occupy." Yes, that is one interpretation. But, it is not the only interpretation. That's my point. Some people think of electrons differently, and AFAIK, so far, nobody's done an experiment that proves which interpretation is the correct one. – Solomon Slow Sep 11 '21 at 17:59
  • @SolomonSlow What is some other interpretation? I've not studied quantum mechanics in detail, but in the few courses I did during my bachelors, this was the only interpretation we were taught. – Mechanic Sep 11 '21 at 18:07
2

In general, if you can accept that, say, a styrofoam brick is lighter than a metal brick of the same size, then you are accepting that different materials can have different densities. If you ever held a tungsten brick in your hand you would br very surprised if how much density can differ.

It shouldn't be a far leap to then extend this acceptance to the fact that even larger densities can happen, at least theoretically. Looking into the mass vs size of for example black holes indicates for us that enormous densities do exist our there. Same goes for the nucleus particles of atoms that compactly form nuclei that are incredibly small. Possibly it is one of these calculations your class has tried to make.

Steeven
  • 50,707