Clothes tumble in the dryer and cling together,
Shocks from a door knobs after walking across carpet,
Sparks of electricity after pulling off clothes,
Bolts of lightning across the sky,
A bad hair day…
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 Protons
- found in the nucleus of atoms
- positive charge
 Neutrons
- found in the nucleus of atoms
- no charge
 Electrons
- found outside the nucleus
- negative charge
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 Electrons
are removed and added to
atoms
 This
process is the focus of static
electricity
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 Positive
- possesses more protons than electrons
 Negative
- possesses more electrons than protons
 Neutral
- equal number of protons and electrons
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CONDUCTORS
 Materials that allow
electrons to transfer across
the entire surface of an
object
INSULATORS
 Materials that do not allow
electrons to transfer across
the surface of an object
 The charge will remain at
the location of charging
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 Opposites
Attract
 Likes
Repel
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FORCE OF REPULSION
1 WAY

The only way that two
objects can repel each
other is if they are both
charged with the same type
of charge
FORCE OF ATTRACTION
2 WAYS


One object is neutral and
the other object is charged
Both objects are charged
with opposite charges
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 Any
charged object – positively charged
or negatively charged – will have an
attractive interaction with a neutral object
 Example:
Paper pieces
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 The
process of separating opposite
charges within an object
A
charged object can cause electrons to
move within an object so that one side is
positive and the other side is negative
 The
object remains neutral
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 Example
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 The
charge an object has is measured in
Coulombs (C)
 An
object would need an excess of 6.25 x 1018
electrons to have a total charge of -1 C.
 An
object with a shortage of 6.25 x 1018 electrons
would have a total charge of +1 C.
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 The
charge on a single electron is -1.6 x 10 -19
Coulomb.
 The
charge on a single proton is +1.6 x 10 -19
Coulomb.
 The
quantity of charge on an object reflects the
amount of imbalance between electrons and
protons on that object.
 Physics
Classroom Examples
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


Rubbing an Object
Two objects have equal
and opposite charges
Transfer occurs from
the least electronloving material to the
most electron-loving
material
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 Uncharging
 Removing
excess charge on an object by
means of the transfer of electrons
between it and another object of
substantial size (your body, the earth,
etc.)
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

Charge the
neutral object
by contact
with a charged
object
Both objects
have the same
charge as the
initial charged
object
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 Method
to charge an
object without
actually touching the
object to any other
charged object
 The
object being
charged receives a
charge that is
opposite that of the
charged object
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Negative Charge
Positive Charge
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 Electrophorus
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 The
electrical force between 2 charged
objects is directly proportional to the
quantity of charge on the objects and
inversely proportional to the square of the
separation distance between the objects
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F
– electrical force, (N)
 k = 9.0 x 109 N*m2/C2
 Q – charge on each object, (C)
 d – distance between objects, (m)
 Physics
Classroom Examples
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 Electrical
forces are extremely sensitive to
distance.
 Greater the distance that separates the
charges leads to less electrical force.
 Physics
Classroom Examples
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 Exist
around any object carrying a
charge.
 The
direction of the electric field is in the
direction that a positive test charge
would be pushed or pulled if placed in
the space surrounding the source charge.
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Electric Field Strength = Force/Charge
E = F/q
E = kQ/d2
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 Always
extend from a positively charged
object to a negatively charged object,
from a positively charged object to
infinity, or from infinity to a negatively
charged object
 Never
cross one another
 Are
most dense around object with the
greatest amount of charge
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Negative Charge
Positive Charge
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 Several
electric field line patterns are
shown in the diagrams below. Which of
these patterns are incorrect?
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 Consider
the electric field lines shown in
the diagram below. From the diagram, it
is apparent that object A is ____ and
object B is ____.
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 Consider
the electric field lines drawn at the
right for a configuration of two charges. Several
locations are labeled on the diagram. Rank
these locations in order of the electric field
strength - from smallest to largest.

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