Chemistry in a Bottle

Are you familiar with the dynamic density bottle experiment? This interesting experiment was invented by Lynn Higgins, and is sold by various science supply companies. Two immiscible liquids (usually salt water and isopropyl alcohol) and two different types of plastic pieces are contained within a dynamic density bottle. The plastic pieces display curious floating and sinking behavior when the bottle is shaken. 

On the Surface: Mini-Activities Exploring Surface Phenomena

In this Activity, students investigate surface tension and surfactants. They count the number of drops they can place on a penny, attempt to make a "square" of drops, and create bubbles using differently-shaped wands. These mini-activities could be used to introduce surface tension and surface area when discussing properties of liquids and gases.