Question: how small are particles

Andres Olivares del Campo answered on 9 Nov 2016:

This depends but they are pretty small.

Actually, the size of a fundamental particle is not very well understood, but we can think of it in terms of how close you need to be to its centre, to feel it: Like for example, if you are hit by a very big ball, you are far away from its centre when you get hit, but if the ball is very small, you have to be very close to its centre when it hits you!

Then, for example, the electron is around 0.0000000001 meters, whereas the neutrino is 100 times smaller. So very very small things!