Download Science 9 Electrical Devices Energy is the ability to do The four most

Science 9
Electrical Devices
Energy is the ability to do
•
The four most common forms of energy are:
1) Chemical or
chemicals, released when the chemicals react.
2) Electrical - energy of charged
place to place.
energy stored in
, transferred when they travel from
3) Mechanical - energy possessed by an object because of its
potential to move.
or its
4) Thermal - kinetic energy of a substance
Energy can be converted to various forms of energy
• Batteries convert
energy into
energy
• Generators convert
energy into
energy
• Electric motors convert
energy into
energy
Chemical Energy
•
•
•
•
Chemical energy is the energy found in
, including food.
Glucose molecules are used in your body cells to produce
energy
and
energy.
Chemical energy can also be converted into mechanical and
energy
(a CD player).
Chemical energy can also be transformed into mechanical energy, with
and light (dynamite).
Electricity to Heat
• Electric energy can be converted to
energy
• Usually converted by inserting a highly resistant material (ex. Nichrome wire) in the path
of the electric current
• Examples:
, heating blankets,
,
toaster, kettle)
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Electricity and Thermal Energy
• Heat (
) can also be converted into electrical energy
– A thermocouple is a device that can convert
energy into
energy.
• It consists of two different metals (
)
joined together that conduct heat at slightly different
rates.
– As one end is
and the other is
. This
causes a current to flow through the wires 
•
Thermocouples can be
by changing the types of
metals
– Usually made of
or
and a
copper/nickel
Thermocouples are useful for measuring temperatures in areas that are difficult to access or
too hot for a regular liquid-filled thermometer.
Example:
Electrical and Mechanical Energy
•
•
In 1820, Danish Scientist Hans Christian Oersted discovered that current flowing
through a wire creates a magnetic field around the wire
In 1831, Michael
made a device that used electromagnetic
forces to move an object led to the
Electricity and Motion
–
–
Electric energy can be converted into
• Examples:
Motion can also be converted into
energy
energy
2
–
Most electricity comes from the
energy into
of
energy
Electricity and Light
•
Electric energy can be converted into
energy
– Example:
• Has a
of highly
metal
(
) which glows brightly when current passes through
it.
Light to Electricity
•
•
Solar energy is converted into
(solar) cells
When light strikes the cell,
produced
– Called the
energy with the use of
are set in motion and a current is
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Electricity to Motion
•
•
•
The
produces sound by
converting
into motion (
).
When a piezoelectric crystal, such as quartz, or Rochelle salt is connected to a potential
difference, the crystal expands or contracts slightly.
Material touching the crystal experiences
, creating sound
waves or vibrations.
Electric and Magnetic Fields
•
•
When electricity passes through a wire a magnetic field is developed
When a changing magnetic field influences a wire a current is induced
Electromagnets
•
A strong electromagnet can be made by
(copper) wire around
a (iron)
. When attached to an electrical source it will
produce a strong
.
•
To keep the electromagnet spinning you need to
the direction
that the current travels through the coil as it aligns with the magnetic field of the
permanent magnetic.
• useful since they
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