As you learn in Chapter 3, Avogadro's number tells you how many atoms, or molecules, there are in 1 mole. The name for this number comes from the Italian physicists Amedeo Avogadro. He proposed the theory that 1 mole of a gas at a specific temperature and pressure has the same number of atoms as 1 mole of a different gas at the same temperature and pressure. This theory was proposed in 1811, but Amedeo Avogadro did not have the technology to determine exactly how many atoms made up 1 mole.
It was actually Jean Perrin who discovered the number in 1895. He showed his respects to Avogadro for coming up with the theory that propelled Perrin to make this discovery. Along with this, Perrin continued his work on atoms and received the Nobel Prize in 1926.
