The cloud chamber is filled with isopropyl alcohol vapor. the chamber is warm at the top, extremely cold at the bottom. at a certain height, the temperature is low enough that the vapor will condense to make droplets, a cloud, if there is something for a droplet to form on, a nucleation site. this can be a dust particle, or the ions produced by ionizing radiation traversing the chamber. this is the source of the trails of cloud that appear in the chamber; these are the tracks of high-energy charged particles. if you compared the track of an alpha particle and a beta particle, the track of the alpha particle would be but the track of the beta particle would be

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.