Competency #8
Answer and Explanation
Normally you have a neutral charge, because you have equal amounts of positive and negative charge in your body. Normally your carpet is also neutrally charged for the same reason. Yet in the winter when you come into the house and shuffle your feet on the carpet, and then touch something else, you get a big shock because of a discharge of excess negative charge on your body. How did you get extra negative charge on you?
Answer:
When your shuffled your feet on the carpet, you did work that separated the charges in the carpet, and removed some of the electrons from the carpet. Those electrons went on to you, and then when you touched something else, they flowed off until you were neutral again (the shocking experience). This process is much more noticeable in the winter, because of the lack of humidity. In higher humidity, water in the air helps dissipate the excess charge and prevents charge build-up on you.