Cloud Chamber:
Thin streaks are caused by electrons and muons passing through the cloud chamber.  In particular, very thin straight streaks are from muons.  On the other hand, you see some streaks that are much more concentrated in one place.  They are caused by either by alpha particles or protons.  At the end of the movie, you see two relatively large two blurbs on the lower left corner of the screen, these are caused by the alpha particles.  This video was taken during a trip to Japan in early January, 2007.  
The following footage was taken at the National Museum of Natural History and Science in Tokyo during my trip to Japan recently.  The device used to visualize cosmic ray, consisting of protons, alpha-, beta-particles, and muons, is called a cloud chamber.  It utilizes a similar principle as the air plane leaving behind the jet cloud.  You can see muon and beta particles to be small straight streaks of lines, while protons and alpha particles form localized fat blurb.