ELECTRICITY----STATIC AND CURRENT

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ELECTRICITY----STATIC AND CURRENT
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What is happening in these pictures?
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STATIC ELECTRICITY
A BUILD UP OF CHARGE( electrons ) from one
object to another, without a flow of charge.  
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• 3 ways to create static electricity
• conduction build up of charge by direct contact
  between 2 objects

Van de graph machine
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• 2. Induction build up of charge by force of
  attraction or repulsion WITHOUT touching one
  object to the other ( through open space )
• Balloon Demo with Salt ( sugar )

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An electroscope demonstrates induction
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Static electricity by friction

• 3. Friction build up of charge by rubbing one
  object against another.

Rubbing hair with balloon
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Static friction- study jams

• http//studyjams.scholastic.com/studyjams/jams/sci
  ence/energy-light-sound/electricity.htmhttp//stud
  yjams.scholastic.com/studyjams/jams/science/energy
  -light-sound/electricity.htm

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Write the letter that most applies for each
word.   1.___ Repel A. Objects with opposite
charges come together. 2.___
Electroscope B. Detects charges. 3.___ Attract
C. Objects with like charges jump
apart. Answer the questions. State the Law
of Electric Charges _______________________
________________   _______________________________
_____ List the three ways in which an object can
become charged 5) 6) 7)  
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When an object becomes charged, one object
________ electrons, and one object _______
electrons.  multiple choice  _____ Electric
force is found between a) Charged objects b)
credit cards c) criminals   _____ The area
around a charged particle that can exert a force
is called a) electric force b) electric shock
c) electric field   11. ______ The build up of
electric charges on an object is a)
current electricity b) static electricity
c ) electric discharge    
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Use the word bank to select your BEST answer.  
FRICTION (f) INDUCTION (i)
CONDUCTION (c)   12._____Electron
s transferred from one object to another by
direct contact. 13.____ Charges on an object
rearrange without direct contact when a charged
object is near it. 14. ____Rub 2
objects together. The electrons are
transferred.   15. ____Rub a balloon on a wool
sweater, and place it near a wall. 16. ____
Walking across a carpet.  

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E. True /False. CORRECT the False!!
17.____ A lightning bolt is an example of
electric discharge.   18.____ An electroscope
can tell if the charge is pos. or neg.
19.____ Static electricity is NOT as noticeable
in the summer because of the dryness
in the air.   20._____ Lightning is a result
of the negative charges in the
clouds being attracted to the negative charges on
the ground.  

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http//phet.colorado.edu/en/simulation/balloons201
1 electricity.ppt
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Lightning video

• http//player.discoveryeducation.com/index.cfm?gui
  dAssetId5AE05296-1087-4C59-A5B9-4585869125DCblnF
  romSearch1productcodeUS

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Ice hockey simulation

• http//phet.colorado.edu/en/simulation/electric-ho
  ckeyhttp//phet.colorado.edu/en/simulation/electri
  c-hockey

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Current electricity

• Current is a flow of electric charges. It is not
  a build up of charge that is discharged.
• All current elec. needs a circuita pathway for
  electric charges to flow..
• All circuits must have at least 3 parts
• 1) wires, 2) a source and
  3) a load(s).

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Parts of a circuit
wires
Source of electricity
Load
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Conductors

• Conductor a material that easily allows the
  flow of electric charges.
• It gives very little resistance to the flow of
  charge. ( metals copper, aluminum , etc )

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Insulators

• Insulators do not easily allow for the flow of
  electric charges through them.
• Ex glass, plastic, certain rubber materials,
  cloth.

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Current electricity brain pophttp//www.brainpop
.com/technology/energytechnology/currentelectricit
y/

• http//www.brainpop.com/technology/energytechnolog
  y/currentelectricity/

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Types of circuits

• http//www.brainpop.com/science/energy/electriccir
  cuits/http//www.brainpop.com/science/energy/elect
  riccircuits/

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Law of electric Charges

• Like Charges repel Unlike charges attract.

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2 main types of circuits

• 1. Series Circuit only 1 path for the electric
  charges to flow
• 2. Parallel Circuit has More than one path for
  the electric charges to flow.

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Series circuit
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Now, lets draw it in your notes
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Resistance

• This is what slows down the movement of the
  electric charges so they hit each other more
• What do you think could ADD resistance in a
  circuit ?
• Add more loads to the same circuit
• Heat
• Longer wires
• Thinner wires

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Circuit Mini Lab

• Take a sheet of computer paper.
• You have 4 drawings, 4 circuits to build, and 4
  questions to answer Lets do the drawings
  together, then you can build, and answer the
  questions
• You Label wires, source, load, direction,
  terminals, switch
• 1. 3.
• 2. 4.

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2. Parallel Circuit has more than 1 path for
electric charges to flow, so if 1 load goes
out, the other loads will still work !
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Draw a parallel circuit
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Circuit simulation
http//phet.colorado.edu/en/simulation/circuit-con
struction-kit-dc
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Alternating Current - AC

• Electric charges move back and forthhomes and
  buildings.
• Ex 60 V one way and 60 V the other way, 120
  Volts

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Lets recap

• 2 types circuits 2 types current direction

1 way
Direct current
Series
Parallel
Alternating current
Back and forth
Direct with a battery
One way
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BATTERIES

• Electrolytes- liquids/acids that cause a chem.
  reaction, that releases electric charges
• Batteries (usually) are DC-direct current- where
  the electrons flow only in 1 direction.

• CONVERT CHEM. ENERGY TO ELECTRICITY.
• 2 TYPES
• DRY CELLS
• WET CELLS
• Dry cells have paste-like electrolytes, and these
  are the batteries you are used to using.
• Wet cells have liquid electrolytes. ( car
  batteries)

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Wet cell
dry cell
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Inside a dry cell
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Inside a wet cell
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Watch the stick figures move the charges Back
and forth, creating a potential difference In
voltage, making current !
http//phet.colorado.edu/en/simulation/battery-vol
tagehttp//phet.colorado.edu/en/simulation/battery
-voltage
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Circuit breakers and fuses
Circuit breaker-open a circuit to keep from
Overload.
Plug fuses

• Circuit breaker

fuses
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CURRENT RESISTANCE VOLTAGE
SYMBOL I UNITS Amperes R or OHMS V Volts
WHAT IS IT? The of electrons. the rate at which charges pass a given point The opposition to the flow of electrons High resistance has more opposition to the flow 4 THINGS THAT AFFECT R Thin/thick wires Temperature Length Wire Type of wire- Copper-good conductor decrease R Iron- poor conductor increase R The energy of each electron. Low voltage little energy. High Voltage High energy
More electronsmore current less electrons less current ? Thickness ? R ? Temperature ? R ? Length ? R
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Ohms law

• I V/ R
• Current voltage/ resistance.
• Discuss wires and resistance!!

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• What current would flow through a resistor of 20
  ohms connected to a 12 V supply? A 240 A
  B 1.66 A C 0.67 A D 0.067AWhat
  current would flow through a resistor of 40 ohms
  connected to a 10 V supply? A 400 A B 4 A
  C 0.25 A D 0.025AA 100 ohm resistor is
  connected to a 20 V supply. What current flows?
  A 0.02 A B 0.05 A C 0.2 A D 0.5 A
  E 2000 AWhat value of resistor would be used
  to permit a current of 0.2 A to flow using a 6V
  supply? A 0.03 ohms B 0.3 ohms C 3.0
  ohms D 30 ohms E 300 ohms