Friday, November 2, 2007



Shaving cream
Magnifying glass
Small plate

1. Place a small amount of shaving cream on the plate. Describe it. Is it a solid, liquid, or a gas?
2. Gently, place the penny on top of the shaving cream. What happens? Is the shaving cream a solid, liquid, or a gas?
3. Rub the shaving cream between your fingers. What does it feel like? Does it act like a solid, liquid, or a gas?
4. Examine the shaving cream with the magnifying glass. What do you see? Does it look like a solid, liquid, or a gas?
5. Let the shaving cream sit out overnight. What does it look like now? Let it sit for a few more days. Does it change its state?


Some substances exhibit characteristics, or properties, of more than one state, or phase, of matter. Shaving cream feels like a liquid when you rub it between your fingers. It has gas bubbles in it. It keeps its shape and supports light objects and therefore acts like a solid. When you let it sit for a few days, the liquid evaporates and leaves a very thin solid and spaces where the gas bubbles were. The molecules of the gas, the solid, and the liquid, are dispersed throughout each other, each retaining its own properties. This is referred to as a ‘colloid’.