Physical Science Insight

1
__________
2
Charge and Force

• All matter is made of atoms that contain
  ______________________, and protons
• Recall that protons and electrons in atoms have
  electric charge
• Electrons have a negative charge
• Protons have a positive charge
• When an object has an equal number of protons
  and electrons, the object has no charge

3
Types of electric charge

• Protons w/ ___________ stuck in the nucleus
• ____________w/ - charge freely moving around
  the nucleus in orbits

4

• Neutrons have _____________
• Neutrons have no effect on the charge
• Charges in objects can produce a force between
  the objects
• Objects are forced together or attracted when
  their charges are different
• Opposite charges attract
• Same electric charges they push apart
• Like charges repel

5
Electric Charge

• An electrical property of matter
• that creates a __________________objects.
• Depends on the imbalance of protons and
  electrons. i.e. net electric charge
• Measured in________________, C

6

• Every charge has an electric field that surrounds
  it.
• Electric fields exert force that causes other
  electric ____________________________.
• Any charge placed in that field will be pushed
  or pulled by that field.

7
Electric Fields

• Exert a force through ___________in all
  directions from the ________________
• When a charged particle enters the force field of
  another particle it is either_________________
• The diagram represents stronger force as the
  lines get closer closer together

8
Electric Force

• Attraction or repulsion between
• objects due to charge
• _______________________________
• _______________________________

9
____________of Charge

• Charge ________________________but it can be
  ______________ from object to object.
• Contact
• Transferring charge by__________________.
• Induction
• The rearrangement of electrons on a neutral
  object_______________________________

10
Static Electricity

• Static means ________________
• Static electricity is electricity at rest
• _____________ can cause it
• Objects rub together and electrons move from one
  object another.

11
Static Charge

• Latin word Stasis which means Stays
• Objects are typically Neutral w/ the same of
  protons and electrons
• They can become charged by ________________elect
  rons
• NOT PROTONS! They stay in the nucleus!
• The ________________of these charges is Static
  Electricity
• In Static Electricity the charges build up and
  STAY
• they dont flow as they do in electric currents

12
Transferring Static Charge

• Friction ____________________i.e. get shocked
  after walking on the carpet
• Conduction ________________________contact w/
  another object hair standing on end w/ Van de
  Graff machine
• Induction the force field of a highly
  negatively charged object _________________away
  from nearby objects causing them to become
  charged, they then are attracted to each other.
  i.e. statically charged balloon attracts small
  pieces of torn up paper

13
Conductors

• Allow the _____________of electricity
• _____________ electrons that are free to move
  from atom to atom
• metals like aluminum, gold, copper and silver

14
Insulators

• Insulators _________________of electrons
• hold more tightly to their ______________
• plastic, rubber, glass

15
Interactions between charges

• same as in magnetism
• Unlike magnetism were on a magnet there is always
  a on one end and a on the other end of the
  magnet
• electrical charges can exist alone
• Like charges _________
• ________ charges attract

16
Static discharge

• Eventually static electric charge will move.
• ________________may move into moisture in the air
  
• Or quickly in a ________.

17
Electric Current

• Electrons in motion.
• Current The _____________that pass a specific
  point in a circuit in one second
• Voltage how ___________are being pushed.
• Circuit electric current flows through a closed,
  __________________path.

18
Generating Electric Current

• Electrochemical cell (battery) changes
  _______________________. Two types wet cell and
  dry cell.
• Thermocouples a tool that uses differences in
  _____________________electric currents.
• Generator- next chapter but make alternating
  current

19
Types of current

• Direct current electrons that flow in the
  ______________________ in a wire. (DC)
• From batteries
• Alternating current electrons that flow in
  ___________________in a wire. (AC)
• From Genrators
• Used in your home
• Transformers change AC to DC

20
Circuits

• For current to flow there must be a complete loop
• Electric circuit ________________path through
  which electrons travel.
• Electrons flow from negative to positive terminal
• Work is done if there is a resistance in the wire.

21
Circuits

• Resistance is supplied by a resistor.
• A _________________is a device that uses electric
  energy to do work.
• A _________________from the resistor to the
  positive terminal completes the circuit.
• An open __________breaks the circuit.

22
Two Types of Circuits

• ______________ A circuit with only one path.
• All the resistors in a series circuit lie along a
  single path.
• The amount of current in a series circuit is the
  same at all parts of the circuit.
• Resistance in the circuit changes if resistors
  are added or taken away.

23
Series Circuits

• Series Circuits provides __________for the
  electrons to follow
• 1. A break in the circuit stops the flow of
  electricity to all other parts of the circuit
• 2. With multiple light bulbs (more resistance)
  the current reduces the dimmer the lights
  become
• 3. Ammeters should be wired in series

24
________________(2nd type of circuit)

• Parallel circuits The electrons in a parallel
  circuit can travel through more than one path,
  each path is separate.
• If theres a break in one path in the circuit,
  electrons can still flow through the other paths
  and maintain a complete circuit.

25
Parallel Circuits

• Parallel circuits the different parts of the
  circuit are on __________ branches
• A break (burn out light bulb) in the circuit
  doesnt stop the flow to the remaining devices
• Multiple light bulbs will remain the same
  brightness since the resistance is not decreasing
  as it does in a series circuit.
• Each pathway can be separately switched off w/out
  affecting the others
• Household circuits Wired in parallel, with a
  standard of 120 volts
• Voltmeters are wired in parallel

26
Parallel Circuits

• The ___________________________
• Water example again added pipes coming from a
  large tank will allow more water to flow out that
  a single pipe.
• Therefore as resistance degreases, current
  increases they are inversely proportional

27
Schematic Diagrams (Draw the symbols and diagrams
into your notes)

• All circuits need at least the following
• Power supply, wire, resistors, other items
  include switches, connectors, meters, etc.
• There is a set of standard symbols used to
  represent these items in a diagram of the circuit

28
Electric power and energy

• Power The rate at which ________________ or
  provides energy The amount of electric power a
  device uses to do work is determined by its
  resistance.
• ______________
• (P) power (V) voltage x (I) current in the
  circuit.

29

• Formula for energy
• ________________
• (E) energy used (P) power x (t) time
• The SI unit for energy is a joule.
• Kilowatt-hour meters measure the electricity used
  in your home.
• (kWh)

30
Circuit Measurements

• ______________- Flow of electrons through a
  material
• Electrical Potential
• Similar to potential energy (lifting something
  higher against the force of gravity gives it
  greater potential_________, increasing its
  potential energy.)
• When given the opportunity, objects will move
  from higher potential energy to an area of lower
  potential energy
• Electrical potential is related to their
  electrical fields and not to height as
  electrons build up on one side they want to
  flow to an____________________________

31
Voltage

• Voltage causes current to flow through an
  electrical circuit
• _______ unit of measure to measure this
  potential
• A Voltage Source (battery or generator) is
  required to maintain the electrical potential in
  a circuit.

32
Electrical Current

• Water flowing thru a pipe depends on more than
  the angle of the pipe. It also depends on the
  length of the pipe, diameter of the pipe and if
  the pipe is clogged or open.
• Electrical Current is ____________________
• Amount of Electrical Current ( amps) depends on
  more than just_______, it depends on
  the_______________ found in the circuit.

33
Electrical Resistance

• the opposition to the flow of electricity
• __________________ symbol is the Greek letter
  Omega -
• Water flowing thru a pipe depends on more than
  the angle of the pipe. It also depends on the
  length of the pipe, diameter of the pipe and if
  the pipe is clogged or open.
• Electricity will take the path of least
  resistance
• The greater the resistance, the less current
  there is for a given voltage.
• A_____________have greater resistance than short
  wires
• b. Thin wires have more________________ than
  thick wire
• c. _______________have less resistance than
  insulators

34
Ohms Law

• The relationship among current, voltage, and
  resistance.
• Ohms law states that the _______in a circuit is
  equal to the ______ divided by the
  ________________
• I V R

35
Electric safety

• Many appliances are equipped with a
  _________________on the plug.
• The ground wire prevents ____________. The
  rounded third prong of a three-way electric plug
  is attached to the ground wire.
• It constantly moves static electricity from the
  appliance to the ground.

36

• Broken wires or water can cause electric
  appliances to short-circuit.
• A _____________occurs when electricity takes a
  short path and bypasses the resistors in the
  circuit.
• Because of this the resistance of the circuit is
  less and the circuit wire increases.
• The increased current can produce enough heat to
  melt wires and start a ______, or cause
  serious___________________.

37
Circuit protectors

• ________________protect against overloaded
  circuits.
• A number on the fuse indicates the max. current
  that will flow through it.
• Circuit breakers are often used in place of
  fuses. A circuit breaker is_______________
  automatically when electric current in a circuit
  reaches its max.