I'm studying A Level physics. I've read that a bubble chamber only shows up particles with a charge, as they ionize the hydrogen in the chamber, leaving tracks, whereas neutral particles don't show up. Is it therefore true then that only charged particles ionize? Because UV-radiation is ionizing and photons don't have a charge. Is it that charged particles are the only ones to ionize in the circumstances, i.e. in hydrogen? Hope this makes sense.