MYELECTRCITY

MANUAL

Electric ChargesAtomsElectronselectrical chargeThe Law of Electrical

Chargeelectric forceelectric field

• All _________ is made up of very small particles called atoms.

• Atoms are made of even smaller particles-_______, _________, and ________.

• The charged particles of atoms are protons and electrons—protons are ________ charged and electrons are ________ charged.

• _________ is a __________ property-an object can have a positive charge, a negative, or no charge.

• Charged object exert a ________-a push or pull-on other charged objects.

• The Law of ___________ -states that like charges _______, or push away and opposite charges ________.

• Because protons are positive and electrons have opposite charges, they are _________ to each other.

• The ____________is the force between charged objects.

• There are two factors that determine the size of the force are:

• The _______ of the charge on the object —the _________ the charge—the _________ the electric force

• The ________ between the charges —the _________ together the charges are—the ________ the electric force.

• An ______________ -the region around a charged object in which an electric force is exerted on another charged object.

Static Electricity FrictionConductionInductionConservation of ChargeElectroscopeelectrical conductorelectrical insulatorstatic electricityelectric discharge

There are three ways to charge an object: friction, conduction, and induction. Atoms become charged when they gain or lose electrons.

________ – charging by ________ happens when electrons are “_______” from one object onto another. Ex: Using a cloth and rubbing a plastic ruler- the electrons move from the cloth to the ruler.

____________ -when electrons move from one object to another by _____ ______. Electrons can be transferred from a positively charged object to an _________ object. Ex: A negatively charged plastic ruler touches an uncharged metal rod.

The rod becomes negatively charged by conduction. ___________ -happens when charges in an uncharged metal object are

_________ without direct contact with a charged object. Ex: If you hold a metal object near a positively charged object, the electrons in the metal are attracted to and move toward the positively charged object.

_________ of Charge - When an object is charged by ANY method, NO charges are created or destroyed. Because charges are not created or destroyed, charge is said to be conserved.

____________ – used to detect whether an object is charged. Electrical ________ is a metal material in which charges can move easily.

Most metals are ______ conductors because some of their electrons are free to move. Ex: copper, aluminum, and mercury

Electrical _______ materials in which charges do not move easily. They do not conduct charges very well because electrons cannot flow freely. Ex: plastic, rubber, glass, wood, and air

_______________ is the electric charge at rest on an object; generally produced by friction or induction.

The term ______ mans “not moving” so the charges do not move away from the object they are in.

_______________ is the release of electricity stored in a source or the loss of static electricity as charges move off an object. Ex: clothes stuck together by static electricity – this happens slowly.

Sometimes electric discharge happens quickly. One of the most dramatic examples of electric discharge is _________.

Electricity Current Electric Current

Alternating Current (AC)Direct Current (DC)

• _______________ – is the rate at which charges pass a given point.

• The ______ the current is, the greater the number of ________ that pass the point each second.

• Electric current is expressed in unit called ___________ – which are often shortened to amps.

• The symbol for unit ampere is ____

• The symbol for current is the letter ______

• When you flip a switch, an electric field is set up in a wire at the speed of light.

• The electric field causes the free electrons in the wire to move. The energy of each electron is transferred _______ to the next electron.

The electric field is created so _________ that all electrons start moving through the wire at the same instant

• There are two kinds of electric current

• _____ current (DC) and

• ______ current (AC)

• In ________ current (DC) the charges always flow in the ________ direction.

• The electric current from the batteries used in a camera is DC

• In _________ current (AC), the charges continually shift from flowing in ______ direction to flowing in the _______ direction.

• The electric current from outlets in your home is AC.

Voltage and Resistance

Voltage

Resistance

• _____________ – is the potential difference between two points in a circuit, (the push behind the current)

• Voltage is expressed in the unit _____ (V).

• In equation, the symbol for voltage is the letter ____.

• Voltage is a measure of how much _______ is needed to move a charge between two points.

• Think of voltage as the amount of energy released as a charge moves between two points in the path of a current.

• The _______ the voltage is, the _______ energy is released per charge.

• As long as there is a voltage between two points on a wire, charges will _____ in the wire.

• _____________ – is the opposition to the flow of electric charge.

• Resistance is expressed in the unit _______ (Ω,the Greek letter omega).

• In equations, the symbol for resistance is the letter ____.

• Resistance can be thought of as “____________________”

• The _______ the resistance of a material – the lower the current in the material is.

• If voltage doesn’t change, as resistance goes ____, current goes ______.

• An objects resistance varies depending on the object’s material, thickness, length, and temperature. As resistance ______, current __________. (_____________ RELATIONSHIP)

• Thicker-_____ resistance

• Shorter-_____ resistance

• Colder-______ resistance

GENERATING ELECTRICAL ENERGY

• Energy cannot be ________ or ________. It can only be transformed or changed into other kinds of energy.

• Many things change different kinds of energy into __________ energy.

• __________ convert mechanical (kinetic) energy to electrical.

• ______ and __________ convert chemical or radiant energy into electrical energy.

• The two kinds of cells are wet cells and dry cells.

• ______ cells have liquid electrolytes.

• A car battery is made of several wet cells that use sulfuric acids as electrolytes.

• _______ cells work similar to wet cells, but the electrolytes are solid or paste-like.

• Batteries used in small radios & flashlights are dry cells.

• _____________ – a device that converts thermal energy into electrical energy.

• ___________ – a device that converts light energy in electrical energy.

Electrical Circuits

Electric CircuitsEnergy SourceWireLoad

• ___________ control the movement of electric current by providing ________ for electrons to follow.

• The path of an electric circuit is a __________ pathway.

• An electric circuit allows electrons to flow from a _________ pole (excess electrons) to a ________ pole (deficient in electrons)

• _______________-can be a battery, a photocell, thermocouple, or an electric generator at a power plant.

• ____________-connect the other parts of a circuit. Wires are made of conducting materials that have low resistance such as copper.

• ________-change the electrical energy into other forms of energy which include:

• Thermal Energy

• Light Energy

• Mechanical Energy

• Sometimes a circuit also contains a ________ that is used to open and close a circuit.

• Loads create ___________ when they change energy from one form to another.

• Electrons flow from negative to positive; therefore, a complete circuit must have wires that connect the negative pole of the energy source to the positive pole of the energy source.

• The circuit is established when there is a continuous path for electricity to travel from one end of the energy source to the other end.

Series and Parallel Circuits

Series CircuitParallel Circuit

• In a __________ Circuit there is only ______ path for the electric current or electricity to flow.

• All of the loads in a series circuit share the ________ current.

• Because the current in each bulb is the same, the lights in the circuit glow with the ________ brightness (power) if they have the __________ resistance.

• If there is any break in the circuit, the charges will ___________ flowing.

• When you add more bulbs in a series circuit, the resistance would ___________ so the current would decrease and the bulbs would be ___________ (less power)

• To find the total resistance of a series circuit add the resistance of all the items

(R1 + R2 + R3 +… = Rtotal)

• In a ___________ Circuit there is ______ than one path for the electric current or electricity to flow.

• The electric current _________ so that electrons flow through each of the paths

• If one path is broken, electrons _________ to flow to the other paths

• In parallel circuits the parts are joined in branches such that the “potential difference” (voltage) across each part is the ________.

• The loads in parallel circuits __________ have the same current.

• Branches with lower resistance get _____ current.

• “Electricity takes the path of least resistance”

• Instead of the same current, each load in a parallel circuit uses the same _________.

• Because each bulb uses the _______ voltage, each bulb glows at full brightness, if they have the same resistance, no matter how many bulbs are connected.

• The total resistance of a parallel circuit gets smaller as you add more branches.

(1/R1 + 1/R2 + 1/R3 +… = Rtotal)

Comparing Series and Parallel Circuits• What are the advantages of using a parallel circuit to a

series circuit?

• The ________ in a parallel circuit will _____ work if one of the loads is _______ or missing. You can use one load at a time, even it another load fails.

Voltage is the potential difference between two points in a circuit.

As voltage increases, more electrical potential energy is available to be changed into other forms of energy.

Basically, higher voltage means a faster flow of electrons or electric current.

In a Series circuit, the __________ has to travel through ______ bulb; therefore, adding more light bulbs makes each bulb _________ because the resistance of the whole circuit has increased.

Resistance is how difficult it is for electrons to flow through a material (friction).

Another advantage of a Parallel circuit is that you can ___________ loads that need ________ currents to the same parallel circuit.

For example, you can connect a hair dryer, which needs a high current to run, to the same circuit as a lamp, which needs less current to run.

Description Series Circuit Parallel Circuit

Definition

# of paths

Current through each bulb

Power of bulbs compared to other

type of circuit

Power as you add more bulbs

Common Uses/Examples of

Pros (advantages)

Cons (disadvantages)

Diagram