A soap bubble has a polar end and a nonpolar end. Water is a polar molecule. The polar end of the soap molecules are attracted to each other. The nonpolar ends of the soap molecules stick out from the water and help hold bubbles together. Float a razor blade or needle on water in a Petri dish on the overhead projector.
Surface tension supports the object.
Float in a low, wide container of water. Touch a bit of wet soap to the water inside of the silk loop and notice that it becomes a circle. Sprinkle black pepper over the surface of water in a Petri dish. Add a drop of detergent to the center and watch the pepper spread out. Fill a wide mouthed jar with water, cover mouth with cheesecloth, and fasten securely.