Boo bubbles are a fun, easy project that you can do at home or in your classroom. These bubbles are made with a mixture of Dawn dish soap and water. A contraption is made out of a 2-liter bottle, funnel, cup and a piece of tubing to blow the gas that is produced when warm water is poured over dry ice into the bubble solution to make them nice and big and opaque. Carbon dioxide (dry ice is frozen carbon dioxide) is more dense than the air that surrounds it, so these bubbles always sink.
Life with a Science Teacher is a personal project highlighting my wife and some of the fun, gross, and unexpected science experiments that she does as a teacher. Follow along at http://bryanlawler.com/lifewithascienceteacher.