Introduction to electricity 2 (9th grade)

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INTRODUCION to
Ignacio Anguera de Sojo

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NY 10001
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Electrical energy
Energy: is the ability to do work, where work is done when a
force moves an object.
Electrical energy: is energy that's stored in charged particles
within an electric field.
Electric current
Voltage
Resistance
electric current and electrical
energy

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123 West Main Street, New York,
NY 10001
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1.- Electric Current
When you hear the word 'current,' what does it make you
think of?
electric current and electrical
energy

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123 West Main Street, New York,
NY 10001
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When you hear the word 'current,' what does it make you
think of?
electric current and electrical
energy
Perhaps water
flowing down
a river?
1.- Electric Current

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123 West Main Street, New York,
NY 10001
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When you hear the word 'current,' what does it make you
think of?
electric current and electrical
energy
A river current is the
flow of water
molecules
1.- Electric Current

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123 West Main Street, New York,
NY 10001
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When you hear the word 'current,' what does it make you
think of?
electric current and electrical
energy
Electrical current instead
of water molecules
moving down a river, we
have charged particles
move down a conductor.
1.- Electric Current

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Electric Current: is the flow of charged particles through a
conducting medium, such as a wire.
electric current and electrical
energy1.- Electric Current

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Electric Current: How it works?
electric current and electrical
energy
Atoms in a conducting material have lots of
free electrons that float around from atom to
atom and everywhere in between.
1.- Electric Current

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123 West Main Street, New York,
NY 10001
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Electric Current: How it works?
electric current and electrical
energy
Atoms in a conducting material have lots of
free electrons that float around from atom to
atom and everywhere in between.
The motion of these
electrons is random,
so there is no flow in
any given direction.
1.- Electric Current

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123 West Main Street, New York,
NY 10001
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Electric Current: How it works?
electric current and electrical
energy
Atoms in a conducting material have lots of
free electrons that float around from atom to
atom and everywhere in between.
The motion of these
electrons is random,
so there is no flow in
any given direction.
1.- Electric Current

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NY 10001
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Electric Current: How it works?
electric current and electrical
energy
When we apply a
voltage to the conductor,
all free electrons move in
the same direction,
creating a current !!!!!!
1.- Electric Current

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Electric Current: A curious thing….
electric current and electrical
energy
While the electrical
energy transfers at
nearly the speed of
light, the electrons
need 1 hour to move 1
meter!!!
1.- Electric Current

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NY 10001
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Electric Current: Two types
Direct Current (DC): electrons move in one direction
electric current and electrical
energy1.- Electric Current

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Electric Current: Two types
Direct Current (DC): electrons move in one direction
electric current and electrical
energy
Batteries create a
direct current because
the electrons always
flow from the 'negative'
side to the 'positive'
side.
1.- Electric Current

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Electric Current: Two types
Direct Current (DC): electrons move in one direction
Alternating Current (AC): pushes the electrons back
and forth, changing the direction of the flow several times
per second.
electric current and electrical
energy1.- Electric Current

17. P: 555.123.4568 F: 555.123.4567
123 West Main Street, New York,
NY 10001
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Electric Current: Two types
Direct Current (DC): electrons move in one direction
Alternating Current (AC): pushes the electrons back
and forth, changing the direction of the flow several times
per second.
electric current and electrical
energy1.- Electric Current

18. P: 555.123.4568 F: 555.123.4567
123 West Main Street, New York,
NY 10001
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Electric Current: Two types
Direct Current (DC): electrons move in one direction
Alternating Current (AC): pushes the electrons back
and forth, changing the direction of the flow several times
per second.
electric current and electrical
energy
You've probably never
noticed the lights in
your house actually
flicker as the current
changes direction
because it happens
too fast for our eyes to
detect!!!
1.- Electric Current

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123 West Main Street, New York,
NY 10001
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Why do we need two types of current, and which one is
better?
electric current and electrical
energy1.- Electric Current

20. P: 555.123.4568 F: 555.123.4567
123 West Main Street, New York,
NY 10001
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Why do we need two types of current, and which one is
better?
electric current and electrical
energy1.- Electric Current

21. P: 555.123.4568 F: 555.123.4567
123 West Main Street, New York,
NY 10001
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Why do we need two types of current, and which one is
better?
electric current and electrical
energy1.- Electric Current

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2.- Voltage
Voltage: Potential energy between two points.
electric current and electrical
energy

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Voltage: Potential energy between two points.
electric current and electrical
energy
Voltage pushes electrons through a circuit.
2.- Voltage

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Voltage: Potential energy between two points.
electric current and electrical
energy
If you rode your bike to the top of
the, the higher you move up, the
more potential energy the bike will
contain.
2.- Voltage

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Voltage: Potential energy between two points.
electric current and electrical
energy
In a battery, the higher differences
of charges you have, the more
potential energy the battery will
contain.
2.- Voltage

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2.- Voltage
Electric Current: electrons at a higher voltage will light a
light bulb more brightly or spin a motor faster than will
electrons at a lower voltage.
electric current and electrical
energy

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Resistance: the opposition presented to the current by a
material or device (Ohms, Ω)
electric current and electrical
energy3.- Resistance

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Resistance : Is affected by many factors:
electric current and electrical
energy3.- Resistance
 Material
Thickness
 Length
 Tª

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Resistance : Is affected by many factors:
electric current and electrical
energy3.- Resistance
Any change that causes the
electrons to have more collisions
with the atoms will increase the
resistance of the object.
 Material
Thickness
 Length
 Tª

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Generating electrical energy: cells
electric current and electrical
energy
Electrochemical cell is something that changes chemical
energy to electrical energy.

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Generating electrical energy: cells
electric current and electrical
energy
Electrochemistry
converts
chemically stored
energy directly
into electrical
work: no moving
parts, no steam
engines, turbines
etc.
Electrochemical cell is something that changes chemical
energy to electrical energy.

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Generating electrical energy: cells
electric current and electrical
energy
Parts of the cell: It contains two compartments, each with
an electrode submerged in an electrolyte.
•Electrode: a conductor that connects to a nonmetallic
part of a circuit (electrolyte). One positive (cathode) and
one negative (anode).
•Electrolyte: fluid that conducts electricity.

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Generating electrical energy: cells
electric current and electrical
energy
Anode: electrode at which electrons leave the cell and
oxidation occurs
Cathode: electrode at which electrons enter the cell and
reduction occurs.

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Generating electrical energy: cells
electric current and electrical
energy
Anode: electrode at which electrons leave the cell and
oxidation occurs
Cathode: electrode at which electrons enter the cell and
reduction occurs.
Reduction: occurs when an
element gains electrons:
(Cu2+(aq) + 2 e- è Cuo(s))
Oxidation occurs when an
element loses electron:
(Zno(s) - 2 e- è Zn2+(aq))

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Resistance : Is affected by many factors:
electrical calculations
3.- Resistance
Any change that causes the
electrons to have more collisions
with the atoms will increase the
resistance of the object.
 Material
Thickness
 Length
 Tª

36. P: 555.123.4568 F: 555.123.4567
123 West Main Street, New York,
NY 10001
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Generating electrical energy: cells
electric current and electrical
energy