This 50 ft. long solar bag by Steve Spangler teaches kids about the properties of air and air pressure. Simply fill thin, black plastic bag with air by running (or with a fan, but running is more fun), tie off the ends, and let the sun heat the air inside the bag. Within minutes, the bag rises to the sky and floats like a giant science tube. Included is 400 feet of Solar Bag String to let your Solar Bag fly high and yet still be able to bring it down when you are done. Includes a complete science activity guide. Ages 8 and up.