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Name: Jon S.
Status: other
Age: 30s
Location: N/A
Country: N/A
Date: 2000-2001


Question:
regarding electrostatic discharge, how does relative humidity becomes a factor? this event happens particularly in frigid weather where the humidity is quite low. what's the electrical characteristics of the air then in this case, more positively charged?


Replies:
Jon,

When a bit of static electricity collects up on a surface, all the build-up is the same kind: all positive or all negative. Since like charges repel one another, this charge build-up is trying to spread out into the world. Air does not conduct electricity well. Glass is not a good conductor. If charge collects on a poor conductor, it cannot move. As a result, you get static electricity. When your hand comes in contact with it, a route of escape is provided. The charge spreads out through your skin and your body. This is the shock you feel.

Water is one of the best electrical conductors in existence. When there is some moisture in the air, electric charge can enter the water droplets floating in the air. As droplets bump into other droplets, the charges can spread out even more. The moving droplets also carry charge to other surfaces, often to conductors. The more humid the air, the greater the opportunity to leave the original surface.

Dr. Ken Mellendorf
Illinois Central College



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