Transcript Electric Charge

 QUICK WRITE:
 For
2 minutes, write the three parts of an
atom and what their charges are. Explain
what creates an electric charge (positive or
negative) on something.
 Rules - You MUST write for the entire time,
even if you write the exact same thing over
and over again!
 Protons
= ______ Charge
 Electrons = _________ Charge
 Neutrons =__________ Charge
 When
Protons = Electrons, atoms are
said to be ELECTRICALLY NEUTRAL (no
net charge)

At your table, determine whose First Name comes
LAST in the alphabet. That person will talk first!
Each person will get 20 seconds to talk and MUST
talk the WHOLE TIME.
 I will signal when each person should start and stop.

Person 1: Compare/Contrast Insulators and
Conductors
 Person 2: Which would you want gloves to made out
of if you were an electrician? Why? Which would you
want inside your phone charger and why?

Conductors and Insulators
• Conductors – objects in which
electrical current easily passes
through such as metals and
graphite
• Insulators – objects that resist the
flow of electrical current such as
plastic, wood, paper, and rubber
 Where
is the conductor in these pictures?
How do you know?
 Where
is the insulator in these pictures?
How do you know?



The flow of ELECTRONS through a conductor:
Electrons flow from the negative end of the battery
to the positive end of the battery
(Current/Electricity flows from the positive end of
the battery to the negative end of the battery)
Factors that affect
Force
1.
2.
Distance between
the charges
Amount of charge
 SI
Unit of charge is Coulomb [C]
 What
do these two pictures have in
common? Talk with your partner for 30
seconds and BE PREPARED TO SHARE!
 The
accumulation of excess electric charge.
(not balanced)
 Ex. Lightning
https://www.youtube.com/watch?v=HpIJ3cZURpQ&feature=youtu.be
Quick Write: Which is stronger electric
force or gravitational force? How do
you know?
Be prepared to be
called on! :O
 The
correct answer should be the
Electric Force!
 Like
you witnessed in the video the
electric force can overcome the
gravitational pull of the Earth; and the
Strong Electric Force is responsible for
holding together the protons and
neutrons in the nucleus of an atom.
 Which
of the following objects is a good
conductor?
A. Pure Water
B. Rope
C. Copper
D. Plastic
Which type of force is strongest?
A. Gravitational force
B. Electrical Force
Which of the following balloon
configurations depict the correct charges of
the balloon and wall?
 An
imbalance of electrical charge is also
known as:
A. Charged electricity
B. Static Electricity
C. Contact Electricity
D. Negative Electricity
ELECTRICAL
CIRCUITS
What is this a picture of?
- +
Pay Attention to the direction
before you answer!
What is electric current?
• Electric Current (I) - flows from the
(+) terminal to the (-) terminal of a
cell/battery through wires and
components
- +
Do NOT confuse this with the flow of ELECTRONS which go
from the negative end to the positive end of the battery!!!!
Electric Field
• Electric Field – when the electrons
of a current are in motion, lines of
electric force rotate around the
electron, or between two charges.
 Does
your picture provide Light or No
Light?
 Do
you know WHY?
Open and Closed Circuits
• Open circuit = switch is open = no
current is flowing = bulb does not
light
• Closed circuit = switch is closed =
current is flowing = bulb lights up
Circuit Diagram & Symbols
Cell/Battery
Light Bulb
Wires
Resistor
Light Bulb Resistor
Switch
 Draw
a picture of a SERIES Circuit. Show
a battery and a light bulb in your
drawing.
 Draw
a picture of a PARALLEL Circuit.
Show a battery and TWO light bulbs in
your drawing.
 Be
prepared to discuss your pictures.
Types of Circuits
• Series Circuits – current takes only
one path and is the same at each
point. (One Wire connects ALL)
Series Circuits
• If one bulb blows out, it breaks the
circuit and all the bulbs go out
• If you add more cells/batteries to a
series circuit, the bulbs burn brighter
Types of Circuits
• Parallel Circuits – current takes
more than one path and is NOT the
same at each point. (Multiple Wires)
Parallel Circuits
• If one bulb blows out, there is still
another complete circuit for the
other bulb to stay lit
Draw these circuits in your Notebook.
Label each one as either Series or Parallel.
A – Parallel
B – Series
Conductor or Insulator?
Conductor
Brighter or Dimmer?
Dimmer
Series or Parallel?
Series
Brighter or Dimmer?
Brighter
Series or Parallel?
Parallel
Series or Parallel?
Series
Series or Parallel?
Parallel
Ohm’s
Law
Ohm’s Law
 What
happens to the Resistance when the
Current is doubled and the Voltage stays
the same?
 The
Resistance is halved!
 What
will happen to the Voltage when the
Resistance is tripled and the Current
remains constant?
 The Voltage
is Tripled too!
 What
happens to the Current when the
Resistance is reduced by 1/3 and the
Voltage stays the same?
 The
Current is Tripled!
Measuring Current
Current is measured in units of amperes (A)
•
2A
2A
2A
2A
1A
2A
1A
In a series circuit,
current is the same
at all the points
In a parallel circuit,
current is shared
between all the points
What is the current?
3A
3A
4A
1A
4A
1A
4A
1A
SERIES CIRCUIT
PARALLEL CIRCUIT
Measuring Voltage
• Voltage – the electrical push that a
cell/battery gives to the current
• Voltage is also known as Potential
Difference
•
Voltage is measured in units of volts (V)
Measuring Voltage
3V
3V
3V
1.5V
1.5V
In a series circuit,
voltage is shared
between all the points
3V
In a parallel circuit,
voltage is the same at
all the points
What is the current and voltage?
6V
4A
A
4A
3V
V
3V
V
A
4A
Current
Series
Same
Parallel Split
Voltage
Split
Same
What is the current and voltage?
4A
6V
A
4A
V
6V
A
2A
V
6V
A
2A
Measuring Resistance
•
Resistance – slows down current, adding
components to a circuit increases resistance
•
Resistance is measured in units of ohms (Ω)
•
More resistance = Less current = Less light
In a series circuit, add up all resistance to get total.
Electrical Power
How much voltage gives 5 amps of
current through a 3 Ω light bulb?
I = V/R
V = (5A)  (3Ω)
V = 15V
How much current flows in a
circuit with a 1.5 volt battery
and three 1 ohm resistances
(bulbs) in series?
I = V/R
I = (1.5V) / (3Ω)
I = .5A
What is the voltage drop
across each resistor in the
circuit?
In a series
circuit,
voltage is
shared
between all
the points
9V/3 = 3V
A light bulb with a resistance of
1.5Ω is connected to a 1.5V battery
in the circuit. Calculate the power
used by the light bulb?
P = IV
I = V/R
I = (1.5V) / (1.5Ω)
I = 1A
P = (1A)  (1.5V) = 1.5 W
P = 1.5 W