Armed with a 2-liter plastic soda bottle, matches, and some hot water, graduate student Rachel Kirpes and undergraduate Anna Leemon set off to wow some local children about cloud formation during the Annual Ann Arbor Earth Day Festival last Sunday, the 17th. The kids quickly learned that adding water to the bottle and shaking it was not enough to form a cloud. After adding particles in the form of smoke, a cloud easily formed. How cool?! One spectacularly interested youngster even wanted to take the cloud home. Rachel and Anna also talked about clouds’ dual effects of both cooling the planet (by reflecting sunlight) and warming it (by insulating earth’s heat). What a great day!