Question: What do really small particles actually look like? (Maybe on a bigger scale?)

Deepak Kar answered on 12 Mar 2014:

As I said in the other answer, we dont really see the particles directly. In fact we cant even calculate their size in the conventional sense, like you can measure for a tennis ball. There is a law in physics (called uncertainty principle), which states that for tiny particles, you can measure the position and speed simultaneously with perfect precision. So when cant even measure their position, how can you measure the size or know how do they look?

Rather we can rank them by their mass. The photon and gluon are mass less. The neutrino has almost zero mass, but not quite. The electron has one of the smallest measured masses, 9.10938291 × 10^-31 kg. Thats is a really small number 🙂