If you could invent a perfect particle to find out where atoms are and what they are doing, what would it be like?
Ideally it should:
• Have zero electrical charge – so it can sneak past electrons and protons • Be able to go deep inside stuff and not just measure the surface • Scatter about the same from any type of atom • Have a similar size to the spaces between atoms • Act like a little compass to sense magnetic fields
Luckily, such a particle exists. It’s called a neutron.
And it’s great for seeing light little atoms like hydrogen, where they are and what they're up to.