Download Electricity - Cobb Learning

Electricity
Electric Charge
and
Static Electricity
Electric Charge
 Charged parts of atom
 Protons: positive charge
 Electrons: negative charge
 Atom Visualization
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Positive charges repel each other
Negative charges repel each other
Charges that are different attract each other
Electricity: the interaction between electric charges
Electric Force
 The attraction or repulsion between electric charges
 Electric Field
 Invisible region around a charged object where the
object’s electric force is exerted on other charged objects
 If another object is placed in the way it will either be
pushed away or pulled toward that charged object
 Single Charges
 The greater the distance, the weaker the electric field
 The closer the field lines, the stronger the electric field
 Electric Force Field Visualization
Multiple Charges
 The electric field will be altered when there is more than
one object
 The electric fields of each individual charge combine by
repelling or attracting
Static Electricity
 Typically, atoms are neutral because they contain an
equal number of protons and electrons
 Some objects can become charged
 Protons are bound tightly in the center of an atom but
electrons can leave their atoms
 If an object loses electrons, it has an overall positive
charge
 If an object gains electrons, it has an overall negative
charge
 The buildup of charges on an object is called static
electricity
 In static electricity, charges build up on objects but they
do not flow continuously
Transferring Charges
The Law of Conservation of Charge:
charges are neither created nor
destroyed. If one object gives up
electrons, another object gains those
electrons.
Charging by Friction
Charging by Conduction
Charging by Induction
Charging by Friction
Occurs when two objects rub
together
Object that gains electrons
becomes negatively charged
Object that loses electrons
becomes positively charged
Charging by Conduction
Occurs when two objects touch
Electrons transfer from the object that
has the more negative charge to the
object that has the more positive
charge
This means that a positively charged
object will gain electrons when it
touches an uncharged object
Charging by Induction
Objects do not touch when charges
transfer
The movement of electrons to one part
of an object that is caused by the
electric field of a second object
The electric field around the charged
object attracts or repels electrons in the
second object
Static Discharge
Electrons have a tendency to move,
returning the object to its neutral
condition
Static discharge is the loss of static
electricity as electric charges transfer
from one object to another
This means that when a negatively
charged object and a positively charged
object are brought together, electrons
transfer until both objects have the
same charge
Static Discharge
 Will often produce a spark
 When electrons transfer objects, they heat the
air around the path they travel until it glows
 The glowing air is the spark you see
 Interactive Example: Static Electriciy & Discharge
 Lightning - huge spark of static discharge
 Occurs to restore a neutral condition in the clouds
 Electrons move from areas of negative charge to
areas of positive charge
 Will reach Earth when negative charges at the
bottom of the storm clouds cause the surface of the
Earth to become positively charged by induction
 Electrons will jump between the cloud and Earth’s
surface, which occurs through conduction
Links & Clips
Mythbusters Part 1
Mythbusters Part 2
Brainpop! Static Electricity
Section 1 Vocabulary
Electric force
Electric field
Static electricity
Conservation of charge
Friction
Conduction
Induction
Static discharge