Download Electricity

Electricity...
“Understanding the
movement of electrons”
Energy v Matter
Q? Does electricity have mass or
volume, is it a form of Matter?
• Can the mass of electricity be
found, does an electrical charge
occupy a certain amount of space?
• No, therefore electricity (like heat,
light & sound) is a form of energy not matter.
Energy vs Matter
• It is important to remember that
electricity is form of energy not
matter.
• Therefore, electricity is concerned
with the behaviour of electrical
energy (more than the movement
of matter).
Laws of Electrical Charges
• Oppositely charged objects attract.
• Similarly charged objects repel.
• Charged objects attract neutral
objects.
Atomic Theory Review
• The ‘quantitative’ relationship
between protons & electrons
determines the charge of a given
material.
• A given substance is usually
neutral because the number of
electrons & protons are the equal.
Atomic Theory Review
• Different substances are made up
of different kinds of atoms.
• Some atoms have a stronger hold
on their electrons than others do.
• Therefore, when two different
materials are rubbed together, the
one with the strongest hold on its
electrons will remove electrons
from the other material.
Atomic Theory Review
• The material which gains electrons
becomes negatively charged while
the material that losses electrons
becomes positively charged.
• A static charge is an excess or
deficit of electrons.
Types of Electricity
• Static: “At rest” - when electrical
energy remains stationary in/ on a
charged object.
• Current: “Flowing” - the movement
of electrical energy along a
pathway or ‘circuit’.
Static Electricity
• Induction: process by which a
charged object produces a charge
in another object with out touching
it.
• Conduction: process by which a
charged object produces a charge
in another object by touching it.
Electroscopes
• The Electroscope is a device that is
used to test the presence and
behaviour of a static charge.
• Pith ball Electroscope
• Metal Leaf Electroscope
Current Electricity
• The movement of electrical energy
along a pathway.
• A pathway for electrical energy is
called a circuit. A circuit is closed
when electricity is allowed to flow
around it. When electricity is not
allowed to flow around a circuit it
is considered open.
Circuits
• Series: A circuit where there is only
one path for electricity to flow. All
of the devices on a series circuit
share electrical energy.
The Series Circuit
•Electrical devices are
connected along one path.
•Voltage is shared
between all devices.
•Amperage is not shared
between the devices.
Circuits
• Parallel: here there is more than
one path for energy to take. The
electrical devices are
‘independently’ connected &
therefore do not share electrical
energy.
The Parallel Circuit
•Electrical devices are
connected along more
than one path.
•Voltage is not shared
between all devices.
•Amperage is shared
between the devices.
Voltage (V)
• In order for an object to move
there must be a force applied to
make it move.
Voltage (V)
• As far as electricity is concerned
the force that pushes electrons
around a circuit is voltage.
• Voltage refers to the amount of
‘push’ electrons have in a circuit.
Current/ Amperage (I)
• Amperage (Amps) is the unit used
to measure the flow of current in
an electrical circuit.
• It refers to the number of electrons
that pass a specific point in the
circuit over a given time.
Resistance (R)
• Refers to slowing, hindering or
“resisting” the flow of electrical
energy.
Resistance (R)
• Resistance is used to turn
electrical energy into another form
of energy (heat, light, sound)
through some kind of device.
• Examples: toaster, door bell or
stereo.
Ohm’s Law (I=V/R)
• The amount of current that will
flow through a circuit depends
directly upon the voltage &
resistance.
• The relationship between current,
voltage & resistance is known as
Ohm’s Law.
Electrical Efficiency