Lesson Plan
Google

The Engineering Place: Balloon Flinking [Pdf]

For Teachers 3rd - 8th
A lesson and activity sheet on buoyancy. Students add weight to a helium-filled balloon to keep it suspended so that it won't float or sink, but instead will 'flink.'
Activity
Center of Science and Industry

Cosi Columbus: Buoyant Bubble [Pdf]

For Students 3rd - 8th
Learn about density in this hands-on science experiment. Includes full list of materials, procedures, and scientific explanation of what makes an object float or sink. [PDF]