Question: How did they discover antimatter In the 1930s?

Mark Johnson answered on 12 Nov 2019:

Great question! A brilliant physicist (Paul Dirac) actually predicted that antimatter should exist a few years before anyone discovered it in real life. The first antiparticle to be discovered was the ‘positron’, an antimatter version of the electron. Scientists discovered it by looking at the tracks left by comic rays reaching the Earth from outer space, using something called a ‘cloud chamber’!