http://www.ck12.org Chapter 5. Energy
FIGURE 5.149
- Three ways electrons can be transferred are conduction, friction, and polarization. In each case, the total
charge remains the same. This is the law of conservation of charge. - Conduction occurs when there is direct contact between materials that differ in their ability to give up or accept
electrons. - Polarization is the movement of electrons within a neutral object due to the electric field of a nearby charged
object. It occurs without direct contact between the two objects. - Electrons are transferred whenever there is friction between materials that differ in their ability to give up or
accept electrons.
Vocabulary
- law of conservation of charge: Law stating that charges are not destroyed when they are transferred between
two materials or within a material, so the total charge remains the same.
Explore More
At the following URL, review how charges are transferred through friction. Watch the animation and read the list of
more-positive to less-positive materials. Then answer the questions below.
http://www.regentsprep.org/regents/physics/phys03/atribo/default.htm
- If you rub glass with a piece of plastic wrap, will the glass become positively or negatively charged?
- Assume that after you pet your dog with very dry hands, you touch a metal doorknob and get a shock. Is
electric charge transferred from your hand to the doorknob or the other way around?
Review
- How is charge transferred by a van de Graaff generator?
- Compare and contrast the formation of cations and anions.
- State the law of conservation of charge.
- Explain how conduction and polarization occur, using the example of walking across a wool carpet in rubber-
soled shoes and then reaching out to touch a metal doorknob.