Electricity_1_­_2010.notebook
April 17, 2012
Activity
Electricity and Electrostatics
• Choose a partner.
• Get one balloon and blow it up.
• Rub the balloon against your partner's hair and attempt to stick the balloon to any vertical surface.
Questions:
1. Was this task possible? Why or why not?
2. What was the overall affect of the balloon rubbing on your partner's hair?
Sep 30­9:04 PM
Review
Sep 30­9:06 PM
The Electrical Nature of Matter
Electricity ­ the circulation or movement of electrons
Protons ­ positively charged subatomic particles
Electrons ­ negatively charged subatomic particles
Electrostatics ­ the study of static electric charges
Neutrons ­ a neutral (no charge) subatomic particle
Electric charges ­ a negative or positive quantity of electricity that builds up on an object
Static electricity ­ a charge on a substance that stays in the same place on an object
Sep 30­9:13 PM
Sep 30­9:15 PM
The law of electric charges
In Other Words:
OPPOSITES ATTRACT AND LIKES REPEL
Sep 25­11:33 AM
Sep 30­9:21 PM
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Electricity_1_­_2010.notebook
April 17, 2012
Drag the charged particles to show how they interact.
Law of Electric
Charges
?
repulsion
?
or
TheCheck your answer!
attraction
?
or
attraction
May 29­10:42 AM
Sep 25­11:33 AM
Drag negative charges to these diagrams to
illustrate a positively charged object, a neutral
object and a negatively charged object.
+ +
+ +
+
+
+ +
+ +
+
+
+ +
+ +
+
+
Postive
Neutral
Negative
Electron
Charging Objects
There are three basic ways to electrically charge an object:
• Charging by Friction
•
• Charging by Contact
•
• Charging by Induction
Click here
for the
answer
Nov 28­8:21 AM
Transferring an electric charge from one substance to another by a rubbing action.
Example: Walking across a carpet
­ creates friction between the carpet and the person's shoes produces a charge on both the person (negative) and the carpet (positive).
Sep 30­9:26 PM
Since all atoms do not hold onto their electrons with the same
attractive force, two dissimilar materials rubbed together
will fight for electrons.
Drag the electrons to the material with the
higher affinity.
Pull here
Charging by Friction
Sep 30­9:23 PM
Click here for the
electrostatic series
Neutral wool
Neutral acetate
Nov 28­8:21 AM
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Electricity_1_­_2010.notebook
April 17, 2012
Summary: charging by friction
Neutral cotton
After
Before
Drag the electrons to the material with the
higher affinity.
Neutral gold
Sep 25­11:33 AM
Nov 28­8:21 AM
Charging by ______________ occurs when two
substances are rubbed together. These two substances
are initially ______________. However, after being
rubbed, one object becomes _________________ while
the other becomes _________________. Charging by
friction occurs because ___________________ are free
to move from one substance to another. The
__________________________ determines which
substance will ______________ electrons and which
substance will ________________ electrons.
Drag this to
the target to
reveal the
answers.
neutral
electrons
negative
friction electrostatic series
Click here for the
electrostatic series
gain
lose positive
Nov 28­8:21 AM
If an object gains electrons then it is said to be
___________________________. If a substance loses
electrons it is said to be ________________________.
For example, if an ebonite rod is rubbed with a small piece
of silk, the ebonite will become __________________
while the silk will become _____________. We use
________________________________________ to
illustrate the transfer of electrical charge (electrons
between two substances.
positive
negative
positively charged
negatively charged
Drag this to
Drag this to
the target to
reveal the
answers.
charge distribution diagrams
diagrams
Nov 28­8:21 AM
Charging by Induction
Charging by Contact
Occurs when one object is electrically charged and passes that charge to another object.
Involves transferring an electric charge from one substance to another without contact.
Example: dust (neutral) sticking to your television (negatively charged).
Affinity means an
attractive force.
Oct 12­8:44 PM
Pull here
Example: When you touch a doorknob after rubbing your feet across a carpet. The electrical charge from your body is shared with the doorknob.
Oct 12­8:44 PM
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Electricity_1_­_2010.notebook
April 17, 2012
The Electrostatic Series
Acetate
Glass Wool
Insulator ­ a substance in which electrons cannot move freely from one atom to another.
Fur and Hair
Calcium, Magnesium, Lead Silk
Aluminum and Zinc GAINS
ELECTRONS
Cotton
Insulators and Conductors
Wax
Conductor ­ a substance in which electrons can move freely from one atom to another.
Ebonite
Plastic (Polyethylene)
Carbon, Copper, Nickel
TASK
Rubber
In groups create a list of at least three conductors and three insulators.
Sulfur
Platinum and Gold
Oct 12­8:53 PM
Static Electricity and Winter
Static electricity is more of a problem in winter because cold air is drier and contains fewer water molecules.
Dry air is an insulator, so in winter, any static charge that builds up on our clothes or painted or polished surfaces tend to stay there.
Oct 12­9:13 PM
Grounding
Involves a charged object sharing its charge with the ground.
Oct 12­9:00 PM
Discharging An Object
Occurs when all the excess electrical charge is removed from an object. There are several ways to discharge an object.
Discharge Methods:
1) Grounding
2) Discharge at a point
3) Exposure to air
4) Exposure to light
5) Exposure to radioactivity
Oct 12­9:10 PM
Discharge at a Point
Removes electric charge from pointed objects by pushing the excess charge off the tip or point of the object.
Often seen on aircraft.
Oct 12­9:10 PM
Oct 12­9:10 PM
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Electricity_1_­_2010.notebook
April 17, 2012
Ion
An ion is a charged atom. Nonmetals form negative Metals form positive ions ions because they gain because they lose electrons. electrons.
Zn
Goes to Zn2+
O
Oct 12­9:10 PM
Goes to O2­
Oct 12­9:29 PM
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