Friday, February 19, 2010

surface tension

water molecules maintain a magnetic link bond with one another. 

Okay, to shake his bond, we need to interrupt the electrical field that maintains that grip. 

what better way to show than with 10-mL of water in a petri dish and a small metal needle. 

Aside from a discussion on distribution of weight, students learned that using the tines of a fork will ensure a needle can be lowered slowely onto the water and it will float.

 the key, here, is that the molecular bond of the water is strong enough to suspend the needle at the top of the water.  so, by adding a drop of soap, we disrupt this cohesive electrical bond and the molecules separate enough to permit the needle to sink.

hmmm, is this why soap removes dirt and grime better than water, itself?

what if we replicated this experiment using ocean water?

Have a great weekend, folks.

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