Download Electricity

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You can learn the difference
between kinetic and potential
energy. Kinetic energy is energy
of motion. An object can have
potential energy because of its
position. Any object that is
moving or has the potential to
move has mechanical energy.
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A roller coaster is a good example of
mechanical energy. Mechanical energy
is present in any object that is moving
or has the potential to move.
There are two types of mechanical
energy. The first type, kinetic energy, is
easy to see. Any moving object
has kinetic energy. The faster a roller
coaster moves, the more kinetic energy
it has.
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The second type, potential energy, is energy that
is stored in an object's position. As a roller coaster
is
pulled to the top of the first hill, it stores potential
energy. As it falls, potential energy is changed to
kinetic energy. Later, when the coaster climbs
another hill, it slows down. This is because kinetic
energy is changed to potential energy.
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Heat is a type of kinetic energy. In conduction, heat is
transferred by colliding molecules. In convection, heat is
transferred in currents through a liquid or a gas. In radiation,
heat is transferred by electromagnetic waves.
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I am melting
because heat is
being transferred
inside of me!
Heat moves, or flows, from warmer objects to cooler
ones. Heat keeps moving until both objects are at the
same temperature. In this process, the warmer object
loses heat energy and the cooler object gains heat
energy.
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The electromagnetic spectrum is the entire range of
visible and invisible electromagnetic waves. The
visible spectrum is the part of the electromagnetic
spectrum that the human eye can see. Light bends, or
refracts, when it passes from one material to another.
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Light bends when it moves from one material into
another. This is called refraction. Refraction can cause
a spoon or pencil in a glass of water to appear bent.
Refraction can also cause underwater objects, such as
fish, to appear closer to the viewer than they really are.
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Other objects, such as books, absorb and reflect
light energy. Reflected light energy allows you to see
an object. When you read a book, light reflects off a
page into your eyes.
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A vibration is a repeating motion up and down or
back and forth. A sound wave is a disturbance in a
material that transmits energy without
moving the material very far.
Click the tuning fork to go to a link
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Gently place your palm against the front of your
neck. Hum softly. What do you feel? You feel the
vibration of your vocal cords. As you hum, talk, sing,
shout, cry, and so on, your vocal cords vibrate. Almost
any vibrating object produces sound waves.
Waves are disturbances that transmit energy through
a material. The vibration of your vocal cords produces
sound waves in the air. These waves carry sound
energy away from their source.
Feel the
sound
vibrations
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Everything in the world is made up of atoms.
Each atom has smaller parts in it. One of
those parts is called electrons. Electrons can
move from atom to atom. When an electron
moves to a different atom, it causes another
electron to have to move.When electrons move
quickly from one atom to another is it called
Electricity!
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Inside an atom,
electrons have a
negative charge
and protons
have a positive
charge. These
particles attract
each other.
A charge is a
measure of the
extra positive or
negative particles
that an object has.
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Electrical energy can be transferred in a circuit. Electric current
flows easily through conductors. A conductor is a material that
current can pass through easily, like metals such as copper.
Electrical energy has many purposes and is very useful. It can
be transformed into almost any other form of energy. Many
devices in a home are designed to convert electrical energy into
other forms of energy. Electric lamps produce light energy.
Radios produce sound energy. Ovens, irons, and toasters
transform electrical energy into heat. Other devices, including
fans and can openers, convert electrical energy into mechanical
energy.
My X-Box
needs
electricity!
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All of the devices that depend on electrical energy
contain circuits. A circuit is an unbroken path through which
electric current can flow. The path is often copper wire, which is
a good conductor-a material through which current can flow
easily. A circuit transfers electrical energy from a power source
to a device that converts electrical energy into another
form of energy.
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• A series
circuit is a
circuit that
has only one
path for the
current.
• A parallel
circuit has
more than
one path
for current
to travel.
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parallel circuit (wire)
• Lights in our homes are wired in
parallel circuits.
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• A resistor is a
material that
resists, but
doesn’t stop the
flow of current.
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• An insulator is a material that
current cannot pass through easily,
like plastic.
The plastic covering over the
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cord is an insulator
Static electricity is the
charge that stays on an
object.
Unlike charges attract
each other, and like
charges repel each
other.
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• An electric
cell supplies
energy to
move charges
through a
circuit, like a
battery.
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The steady flow of
electricity is called
an electric current.
A current will move
along a wire or a
path called a circuit.
Circuit means to “go
around.”
A Simple Circuit
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