A cloud chamber is a nifty little piece of equipment that you can use to observe high energy particles. Those little white streaks you're seeing through the mist? They're the tracks left behind by cosmic rays moving through saturated alcohol vapor. The rays ionize the atoms of vapor as they pass by, leaving a trail of condensation. Better yet, you can build one at home and impress your friends. (Big thanks to our own Arkizzle for the fabulous recommendation!)
Thumbnail image courtesy Flickr user milgrammer, via CC
