ELECTRICITYELECTRIC CHARGESAtoms are composed of _________ main parts. _______________, p+, positive, located in the nucleus;

________________, no, neutral, located in the nucleus; ____________________, e- , negative, located

outside the nucleus in the electron cloud. Everything is made of ________________.

Protons and electrons have a property called _________________________. An atom has __________

numbers of positive and negative charges so they _________________ each other out. Electrons can

__________ from one atom to another atom. This movement is called ____________________.

STATIC ELECTRICITYSome atoms hold their charges more ____________. Latin word “stasis” which means ___________.

Static electricity is the ______________________ building up of charge on an object. Protons _______

move. Only _______________ move. In static electricity, the charges ___________________________

– they do not _________. When you walk across a carpet, __________________ causes electrons to

move from the carpet to your shoe. This is a build-up of static electricity. You ____________________

the electricity by touching a _________________________.

LAW OF CONSERVATION OF CHARGEWhen an object becomes charged, the electric charge is _______________________________________

– it just ________________ from another object. Static electricity is an ______________________ in

the amounts of positive and negative charges on the surface of an object.

Another way to generate static electricity is with a ______________________ generator. American

physicist Robert Jemison Van de Graaf invented the Van de Graaf generator in 1931.

There are _____________ ways to charge on object:1. Charging by ______________ - The charge is transferred because of rubbing two objects

together. Example: shoes on a carpet

2. Charging by ______________ - Involves the charging of one object by another object

_______________________ direct contact. Example: balloon and rice cereal/electroscope

3. Charging by ______________ - Involves the ________________________________ of a

charged object to a neutral object. Example: Van de Graaf generator

Objects do not hold a static charge ________________ – objects tend towards ____________________

– they want to be neutral. When electrons move toward this equilibrium – static discharge occurs.

- __________________ – water (a polar molecule) vapor in the air pulls electrons off

negatively charged objects, preventing static charges to build up.

- _______________________________ - objects reaching static equilibrium

CONDUCTORSAllow the _______________________ of electricity; loosely bound electrons that are free to move from atom to atom. Examples:

INSULATORSInsulators – ___________________ the flow of electrons; hold more tightly to their valence electrons. Examples:

ELECTRIC CURRENTDefine:

REMEMBER:Conductors let electrons move ____________. Insulators do ________ let electrons move easily. A

_________________________ has conductivity somewhere between an insulator and a conductor.

Devices made of semi-conductors, notably _____________________, are essential components of most

electronic circuits.

There are __________ parts to an electric charge1. ___________________ - For electrons to flow there must be a ___________________________

between two places. This is called voltage which is the ___________ that causes electrons to

flow. It is ____________________________. Charges flow from ________ voltage to _______

voltage. Units: ________________________

2. ___________________ - The measure of _________________________ per second are flowing

through the wire is the amperage. Units: _________________. The number of electrons

flowing per _________________. Electrical current is like the amount or __________________

_______________ flowing through the hose. There are two types of current: AC – __________

current and DC – ____________ current.

3. ____________________ - The tendency for a material to ______________ the flow of electrons.

___________________ materials have ___________________ amounts of resistance to the flow

of electrons. Units: __________________. Examples: ___________, ____________, and

_____________ have low resistance, which means that current can flow _____________ through

these materials. __________, _____________, and __________ have very __________

resistance, which means that current ______________ pass through these materials easily.

_________ wires provide more resistance than do _________ wires. Resistance in wires

produces a _________ of energy (usually in the form of __________), so materials with no

resistance produce no energy loss when currents pass through them. Resistance also depends on

______________________, usually increasing as the temperature ___________________.

OHM’S LAW

In a material, the current (I) is ________________ proportional to the voltage (V) and

____________ proportional to the resistance.

Water in a Hose DC in a Wire Electrical UnitsVoltage (potential) (V)

Current (I)

Resistance (R)

PRACTICEWhat is the current produced with a 9-volt battery through a resistance of 100 ohms?

BATTERIESTWO TYPES:

1. ___________ Cell – the electrolyte is not really dry; but is a paste.

– Standard AA, C, D type batteries, electrolyte is a paste. The “+” terminal is carbon.

2. ___________ Cell – the electrolyte is a liquid (car battery)

– In a car battery, the electrolyte is sulfuric acid.

Batteries have three parts: a _____________ (+), an _____________ (-), and an __________________.

The cathode (________________) and anode (________________) at either end of a traditional battery

are hooked up to an electrical circuit. The chemical reactions in the battery causes a ________________

of electrons at the anode. This results in an electrical ___________________ between the anode and the

cathode - an ___________________ build-up of the electrons. The electrons wants to ______________

themselves to get rid of this difference. They do this in a certain way. Electrons _____________ each

other and try to go to a place with ___________________ electrons.

ELECTRICAL CIRCUITDefine:

Four Parts: 1. Energy Source, 2. Load, 3. Wires, 4. Switch

OPEN CIRCUITS – pathway is ___________. CLOSED CIRCUITS – pathway is ________________.

SERIES CIRCUIT

Provides only _________ path for the electrons to follow. A break in the circuit _________ the flow of

electricity to all other parts of the circuit. With multiple light bulbs (more resistance) the current

______________ and the lights become ________________. Ammeters should be wired in series.

RULES: 1. The _____________ current flows through each part of a series circuit. 2. The _________

resistance of a series circuit is equal to the ___________ of individual resistances.

PARALLEL CIRCUIT

The different parts of the circuit are on _______________ branches. A break (like a burned out light

bulb) in the circuit ___________ stop the flow to the remaining devices. Multiple light bulbs will

remain the __________ brightness since the resistance is ________ decreasing as it does in a series

circuit. Each pathway can be separately ____________________ without affecting the others.

Household circuits – Wired in ________________, with a standard of 120 volts. Voltmeters are wired

in parallel. The ____________ paths, the _____________ the resistance. Water example again: added

pipes coming from a large tank will allow ___________ water to flow out that a single pipe. Therefore

as resistance _________________, current __________________; they are inversely proportional.

RULES: 1. Voltage is the __________ across each component of the parallel circuit. 2. The _________

of the currents through each path is equal to the ____________ current that flows from the source.

Question: What is the major difference between a series circuit and a parallel circuit – in your own

words:

SCHEMATIC DIAGRAMS

All circuit drawings need at least the following: __________________, ______________________,

__________________, ___________________, other items include connectors, meters, etc. There is a

set of standard symbols used to represent these items in a diagram of the circuit.

LIGHT BULB - Electricity flows through the circuit. If the bulb is _______________, so is the circuit.

TRANSPORTING ELECTRICITY - A _____________________ is a device that increases of

decreases alternating current generated by a power plant so it can enter homes safely.

ELECTRICAL POWER - The ______________ at which electrical energy is transferred by an electric

circuit. Use Joule’s Law: Power = ________________ x ________________. Unit: ____________. A

___________________________ is what the power company uses to determine how much electricity or

energy you used. Energy used = ______________ (kW) x __________ (hours) or E= P x t. To find

cost, you would multiply the _______________ by the ________________ per kilowatt hour.

PRACTICE

1. 105 V are used to power an appliance that needs 15.0 amps. What is the power used? Power = current x voltage.

2. How much energy is used when this appliance is used for 30.0 days, 24hrs a day? Energy = Power x time.

3. If the power company charges 8¢/Kw-h, what is the cost of the energy above? Cost = Energy x price per kW hr.