Just add some sunshine to make this giant 50 ft. long Solar Balloon soar into the sky! Demonstrates buoyancy, convection, thermodynamics and solar power. Teaches Bernoullis Principle and Pascals Principle. Perfect for classrooms and science projects. Great for science classes and the perfect start to a science project. Bright direct sunlight on a calm, cool day has the Solar Balloon soaring in just minutes. Includes one 50 ft. long by 29 in. diameter Solar Balloon, 400 ft. of string, complete instructions and science learning guide.