Static Electricity
Physical Science
Name: ___________________________________________________ Period: ____ Date: ____________
Essential Question: How do I explain the nature of static electricity?
Static electricity is a stationary electric charge that is built up on a material. A common example of static electricity
is the slight electrical shock that we can get when we touch a doorknob during dry weather. The static electricity is
formed when we accumulate extra electrons (negatively-charged particles which we rub off carpeting) and they
are discharged onto the doorknob.
Producing Static Electricity
Everything is made up of atoms, and atoms are made of tiny particles, some of which are electrically charged. Most
atoms are electrically neutral; the positive charges (protons in the nucleus or center of the atom) cancel out the
negative charges (electrons that surround the nucleus in clouds). Opposite charges attract one another. Similar
charges repel one another.
Sometimes the outer layer (the negatively-charged electrons) of atoms are rubbed off, producing atoms that have
a slight positive charge. The object that did the rubbing will accumulate a slight negative charge as it gets extra
electrons. During dry weather, these excess charges do not dissipate very easily, and you get static electricity.
(During humid weather, the electrons flow through the damp air and the object become electrically neutral.)
Static Electricity Experiments
Try this: Rub a balloon on your hair. This removes some of the electrons from your hair and gives the balloon a
slight negative charge. Now put the balloon against a wall. It will stick (if the weather is dry) since the negative
charges in the balloon will re-orient the atoms of the wall, and a weak electrical force will hold the balloon in place
on the wall.
Try this (for a really bad hair day): Rub a wool (not acrylic) cap on your hair (on a dry day). This removes some of
the electrons from your hair, giving each hair a slight positive electrical charge. Like charges repulse one another,
so each hair repulses the other hairs. The result is a mad-scientist hair-do.
Lightning
In 1751, Benjamin Franklin experimented with electricity in a thunder storm, using a kite, a key and a Leyden jar
(two conductors separated by an insulator; it is a device for storing static electricity). The thunder cloud leaked
electrons (negatively-charged particles) down through the kite's silk sting to the key and into the Leyden jar (on the
ground). Franklin himself was insulated from the electricity; he was holding the portion of the string attached to
the string but not directly to the Leyden jar. When Franklin touched the key, he got a static shock. DO NOT TRY
THIS - many people have died trying it. In 1752, Franklin developed the lightning rod.
Which Objects Lose Electrons Readily?
When two materials are rubbed together (like a balloon and your hair), one will lose electrons and one will
accumulate them. Physicists have ranked materials by the order in which they lose or gain electrons. This ranking is
called the triboelectric series. A small list of some common materials is shown below. When two of these
substances are rubbed together, the one that is higher on the list will usually lose electrons (and accumulate a
positive charge). The ones on the bottom of the list gain electrons (accumulate a negative charge).
http://www.enchantedlearning.com/physics/Staticelectricity.shtml
Clarifying questions:
1. What is static electricity?
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2. How does static electricity form?
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3. How are most atoms electrically neutral?
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4. How do charges interact with one another?
a. opposite charges ( + ) and ( - ) or ( - ) and ( + )
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b. Similar charges ( - ) and ( - ) or ( + ) and ( + )
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5. How does a slight positive charged atom form?
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6. How can object become negatively charged?
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7. Why do you get more static electricity during dry weather than during humid weather?
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8. What would happen if you rub a balloon on your hair during a dry day?
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9. How can you attain a mad-scientist hair-do?
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10. What was the experiment of Benjamin Franklin?
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11. Why was Benjamin Franklin insulated in the experiment?
Triboelectric Series
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human skin
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rabbit fur
12. What happened to Benjamin Franklin when he touched the key?
glass
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human hair
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nylon
13. Why should you not do the same experiment?
sheep's wool
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silk
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aluminum
14. Who developed the lightning rod? What is the lightning rod?
paper
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cotton
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wood
15. What happens when two materials are rubbed together?
amber
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Nickel, Copper, Brass,
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Silver, Gold, Platinum
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acetate, rayon
16. What is the “triboelectric series”?
rubber
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polyester
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PVC
(polyvinylchloride
plastic)
teflon