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## ELECTRICITY----STATIC AND CURRENT

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### Electric Charge and Static Electricity ELECTRICITY----STATIC AND CURRENT 31, 2012 Objectives: Describe how charged objects interact by using the law of electric charges. – PowerPoint PPT presentation

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Title: ELECTRICITY----STATIC AND CURRENT

1
Electric Charge and Static Electricity
ELECTRICITY----STATIC AND CURRENT 31, 2012
Objectives Describe how charged objects
interact by using the law of electric
charges. Describe one way in which an object can
become charged. Do Now What are the parts of an
atom? Do you know? Homework Energy Project
Due tomorrow!!! Make sure you email it to me by
class tomorrow or it will be late!
2
Section 1 Electric Charge and Static Electricity
Chapter 17
3
Law of Electric Charges
• Like charges repel Opposite charges attract

4
Section 1 Electric Charge and Static Electricity
Chapter 17
Electric Charge
• Electricity is the energy caused by the flow of
electrons.
• Charges Exert Force Atoms are composed of
particles with electric charge.
• The law of electric charges states that like
charges repel and opposite charges attract.

5
Section 1 Electric Charge and Static Electricity
Chapter 17
Electric Charge, continued
• The Force Between Protons and Electrons Because
protons and electrons have opposite charges, they
are attracted to each other.
• The Electric Force and the Electric Field The
force between charged objects is an electric
force.
• An electric field is the region around a charged
object in which an electric force is exerted on
another charged object.

6
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7
What is happening in these pictures?
8
March 5, 2013 Do Now Using the Law of Electric
Charges, predict what will happen
• A B C
• Between A B?
• Between B C?
• Between A C?
• Objective define static electricity and
describe the 3 ways an object can become charged!
• Homework Go to Mrs. Anicitos page and open the
lightning assignment. Complete for Thursday!

_

9
Charge and Static Electricity
Chapter 17
• Static Electricity A BUILD UP OF CHARGE
(electrons) on an object!
• Electric Discharge loss of static electricity
• Detecting Charge You can use a device called an
electroscope to see if something is charged.

10
Electric Charge and Static Electricity
Chapter 17
Charge It!
• Friction Charging by friction happens when
electrons are wiped from one object onto
another.
• Conduction Charging by conduction happens when
electrons move from one object to another by
direct contact.
• Induction Charging by induction happens when
charges in an uncharged metal object are
rearranged without direct contact with a charged
object.

11
Static electricity by friction
• 1. Friction build up of charge by rubbing one
object against another.

Rubbing hair with balloon
12
• 2. Conduction build up of charge by direct
• contact between 2 objects

13
• 3. Induction build up of charge by force of
attraction or repulsion WITHOUT touching one
object to the other ( through open space )
• Demo with Salt

14
Study Jams - Electricity
15
3 Ways to Charge an Object
16
FRICTION (f) INDUCTION (i)
CONDUCTION (c)
1._____Electrons transferred from one object to
another by direct contact.
2.____ Charges on an object rearrange without
direct contact when a charged
object is near it. 3. ____Rub 2
objects together. The electrons are
transferred.   4. ____Rub a balloon on a wool
sweater, and place it near a wall. 5. ____
Walking across a carpet.

17
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)
18
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
19
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.

20
1 electricity.ppt
21
Lightning video
• http//player.discoveryeducation.com/index.cfm?gui
dAssetId5AE05296-1087-4C59-A5B9-4585869125DCblnF
romSearch1productcodeUS

22
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

23
Parts of a circuit
wires
Source of electricity
24
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 )

25
Insulators
• Insulators do not easily allow for the flow of
electric charges through them.
• Ex glass, plastic, certain rubber materials,
cloth.

26
Current electricity brain pop http//www.brainpop
.com/technology/energytechnology/currentelectricit
y/
• http//www.brainpop.com/technology/energytechnolog
y/currentelectricity/

27
Types of circuits
• http//www.brainpop.com/science/energy/electriccir
cuits/http//www.brainpop.com/science/energy/elect
riccircuits/

28
Law of electric Charges
• Like Charges repel Unlike charges attract.

29
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.

30
Series circuit
31
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32
Now, lets draw it in your notes
33
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 ?
• Heat
• Longer wires
• Thinner wires

34
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.

35
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 !
36
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37
Draw a parallel circuit
38
Circuit simulation
struction-kit-dc
39
Alternating Current - AC
• Electric charges move back and forthhomes and
buildings.
• Ex 60 V one way and 60 V the other way, 120
Volts

40
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
41
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)

42
Wet cell
dry cell
43
Inside a dry cell
44
Inside a wet cell
45
Watch the stick figures move the charges Back
and forth, creating a potential difference In
voltage, making current !
-voltage
46
Circuit breakers and fuses
Circuit breaker-open a circuit to keep from
Plug fuses
• Circuit breaker

fuses
47
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
48
Ohms law
• I V/ R
• Current voltage/ resistance.
• Discuss wires and resistance!!

49
• 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 0.067A What
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 0.025A A 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 A What 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