Sheri Edwards's List: pppscience

• soap decreases the pull of surface tension
• surface tension in plain water is just too strong for bubbles to last for any length of time
• One other problem with pure water bubbles is evaporation: the surface quickly becomes thin, causing them to pop.
• Soap molecules are composed of long chains of carbon and hydrogen atoms. At one end of the chain is a configuration of atoms which likes to be in water (hydrophilic). The other end shuns water (hydrophobic) but attaches easily to grease
• attaches itself to the grease on your dirty plate, letting water seep in underneath.
• carried off by a flood of water.
• the hydrophobic (greasy) ends of the soap molecule do not want to be in the liquid at all. Those that find their way to the surface squeeze their way between the surface water molecules, pushing their hydrophobic ends out of the water. This separates the water molecules from each other.
• soap molecules decrease the surface tension.
• Because the greasy end of the soap molecule sticks out from the surface of the bubble, the soap film is somewhat protected from evaporation (grease doesn't evaporate) which prolongs the life of the bubble substantially.

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