Download Electric Fields

Mrs. Hooks
Ch. 22 Electricity
Learning Targets
NGSS 2-3, 2-4, 2-5
• 1. I understand that fields exist between
objects and all objects exert a force on one
another, even when they are not in direct
contact.
• 2. I can determine the factors that affect the
strength of a magnetic force.
Electric Charge
*All solids, liquids, and gasses are made up of tiny
particles called atoms.
• Atoms are made up of protons, neutrons, and
electrons. * Strong Nuclear Force holds protons
and neutrons inside the nucleus.
• Protons and electrons have an electric charge and
neutrons do NOT have an electric charge.
• 2 types of Electric Charge are Positive and Negative
• Ions- a positively or negatively charged atom.
• Electrons are constantly on the MOVE!
• The imbalance of electric charge on an object
is called static charge.
– Due to transfer of electrons between objects
– One object is negative and one object is positive
and they attract.
Electric Forces
• All charged objects exert an electric force on
each other.
• The electric force between two objects can be
attractive or repulsive.
-
+
Unlike charges attract.
+
Like Charges repel.
+
-
Like Charges repel.
-
• Electric Force between two charged objects
depends on…..
– 1. the distance between them
– 2. the amount of charge on each object.
REMEMBER!!!!!
1. THE ELECTIRC FORCE GETS STRONGER AS THE
CHARGES GET CLOSER TOGETHER.
- two like charges push away stronger the
closer they are together.
2. THE ELECTRIC FORCE BETWEEN TWO OBJECTS
THAT ARE CHARGED INCREASES IF THE AMOUNT OF
CHARGE ON AT LEAST ONE OF THE OBJECTS
INCREASES.
Electric Fields
• Electric Fields- area that exists around every
electric charge that exerts a force on other
electric forces.
– An electric field gets stronger as you get closer to
a charge, just as the electric force between two
forces become greater as the charges get closer.
Definitions you need to know….
• Electric Discharge- rapid movement of excess
charge from one place to another
– Examples: getting shocked by touching door,
Lightning
• Grounding- process of providing a pathway to
drain excess charge into Earth
Electric Force is the SAME as Magnetic
Force!!!!!
• Magnets attract objects made of iron and steel.
• One end of a magnet is the North pole and one
end is the South Pole.
N
S
N
N
S
S
• Magnetic Force is Dependent upon…
– Distance
– Amount of charge
• Magnetic force is exerted through a magnetic
field
• Magnetic fields surround all magnets.
Insulators vs. Conductor
Induced charge vs. Grounding
• Insulator- materials in which
electrons can not move easily
from place to place
• Induced charge is when an
objects charges separate due
to an electric field.
• Electric Discharge occurs when
there is a rapid movement of
excess charge from one place
to another.
–
–
–
–
–
Plastic
Glass
Rubber
Wood
foam
• Conductor- materials that contain
electrons that can move more
easily in the material.
– METALS such as copper are in
wires.
– Aluminum
– Steel
– Water
– Other metals
– Getting shocked
– Lightning
• Grounding- a way to avoid the
damage of an electric
discharge by providing a
pathway to drain excess
charge, usually by another
conductor.
Electric Current
• Electric Current- Flow of electric charge.
– Model ex- Water Flowing
• Electric charges will flow continuously only
through a closed conducting loop called a circuit.
• Electric circuit contains:
– Source of electrical energy (battery)
– Electric conductor (Wire)
– Lightbulb or other electric device
• Voltage- the measure of how much electrical
potential energy each electron can gain. (V)
• Resistance- the measure of how difficult it is for
electrons to flow through a material
– Depends on- amount of thermal energy produced &
length and thickness of wire
• Copper-_____ resistance- because____________________
• Tungsten-____resistance- because____________________
Electric Circuits
• Ohm’s Law- law showing the relationship
between voltage, current, and resistance in a
circuit.
– According to this law, when the voltage in a circuit
increases the current increases.
Voltage = current X resistance or
V=IR
Series Circuits
• A circuit that has only one
path for the electric current
to follow.
• If the current is broken then
the current will no longer
will flow and all devices in
the circuit will stop working.
Parallel Circuits