6.1
Various Forms and Sources of Energy
Energy is the ability to do work.
Form of energy:
Light
energy
-Objects that produce lights are said that
to have light energy.
-enables us to see things, for the process of
photosynthesis, and supply energy for solar cells.
Kinetic energy
- Present in objects that are moving.
- exists whenever an object that has mass; is in motion.
- increases when it moves faster. Example: moving car, flying bird,
swinging pendulum.
Potential
energy
- Energy stored in an object due to its
position, or its condition when it is lifted up, compressed, stretched or bent.
- Gravitational potential energy is the energy stored in an object when it is
raised from its position.
- Elastic potential energy is stored in objects that
are compressed, stretched or bent.
Sound
energy
- Can be detected by our ears.
- Produced when
we talk, sing, whistle, knock something, clap or play musical instrument.
- enables us to communicate and have entertainment.
- alert
people of something. It produce when object vibrate.
Heat energy
- Raises the temperature of an object.
- Always
travel from a hot region to a cool region.
- can be detected by our skin.
Electrical
energy
- An electric current posses energy as it can
be used to do work.
- produced by an electric charge or current.
-widely used because it can be easily change to other forms of energy.
- Lightning,
bicycle dynamos and power stations also produce electrical energy. It is used
to work machines.
Chemical
energy
- It is the energy stored in substances such
as food, fuels or chemicals.
Nuclear
energy
- Energy stored in the nucleus of an atom.
- Energy
releases when nuclear reaction take place.
- Mostly used to generate electricity.
- Some ships and submarines are powered by nuclear energy. Example: uranium,
plutonium.
Sources of energy:
Hydroelectric
energy
- Electricity generates using water.
- Forcing moving
water to produce electricity. Rotate turbines and dynamos to generate
electricity to hydroelectricity power station.
- Main source of electricity in
world.
Wind
energy
Wind is moving air that contains kinetic
energy. Wind has kinetic energy that is used to rotate windmills for the
purpose of grinding wheat, pounding maize and pumping water for the use of
animals and irrigation.
Wave
energy (Tidal energy)
- Sea rises and fall twice a day.
- Waves have
potential energy and kinetic energy that are used to rotate turbines of dynamos
in wave-generated power station.
- not widely used because it is not
constant but follows the condition of the sea.
- difference in the height of
the water at high tide and low tide is used in a tidal power station to
generate electricity.
- As the tide comes in, water flows through the turbines to
generate electricity.
- The same thing happens when the tide goes out and water
flows in the opposite direction.
Biomass
energy
- Energy that come from biological materials
such as animal faeces, plants and household wastes.
- decay of organic substance
produces alcohol and methane gas.
- used as fuel for producing heat,
working machines and moving vehicles
Solar
energy
- Energy derived from the Sun.
- heat and light
is 2 form of solar energy.
- Solar cells absorb light energy from the Sun
directly and change it into electrical energy.
- Solar cells are used to provide
electricity for calculators, satellites, watches and certain vehicles.
- A solar
heater is used to change energy from the Sun into heat energy which is then
used for heating up water and cooking purposes.
Fossil
fuel
- Combustible material: burn easily to
release heat and light energy.
- supply almost ninety percent of fuel energy
today, it is the most widely used fuel.
- Most of it are used in power stations
to generate electricity. Example: petroleum, crude oil, natural gas, coal.
Geothermal
energy
- comes from the very hot interior of the
Earth in the form of heat energy.
- Most geothermal areas are near volcanoes, hot
spring and geysers.
- can be a tourist attraction, a direct source of heating
and used as an instant steam-generating facility to spin a turbine.
Radioactive
substance
- generates lots of heat energy that can
be used to generate electricity.
- The splitting of atoms in radioactive
substance release heat that can then be used to produce steam.
- Steam turns
turbines and dynamos to generate electricity.
- Energy from radioactive
substances can be used to generate electric energy for ships, submarines,
satellites, meteorological stations and lighthouses.
The
Sun as the primary source of energy
- main source of energy that
supports all forms of life on Earth.
- support almost all type of energy on
Earth..
Energy Change
Energy can change from one form into
another.
1.
A falling coconut loses
potential energy and gains kinetic energy. It has maximum energy just before it
hit the ground.-Potential energy->kinetic energy
2.
A tin with some nails in it is
shaken and sound can be hear.-Chemical energy-> kinetic energy->sound
energy
3.
A paper propeller fan is held
on top of a lit candle and it spins.-Chemical energy-> heat
energy->kinetic energy
6.2
Renewable and Non-Renewable Energy
- Renewable energy sources are energy sources
that can be replaced when they have been used. This means that the supply of
these energy sources will not be used up.
- Non-renewable energy sources are
energy sources that cannot be replaced and will finally be used up.
- Most of the
non-renewable energy pollute the environment but just biomass one type of
renewable energy pollute the environment.
Why
do we need to conserve energy?
To conserve energy resources that may be
used up and can be used for time after this.
How
can we help to conserve energy?
We can help to conserve energy by using
less energy and reducing energy wastage. We must learn how to use energy
efficiently. Here are some ways to use energy efficiently:
1.
develop more efficient engines
of motor vehicles and machines
2.
make sure that engines of motor
vehicles are serviced regularly and are in good condition
3.
switch off electrical
appliances when not in use
4.
use fluorescent lamps which are
more energy-efficient instead of filament lamps
6.3
The Importance of Conserving Energy Sources
We can show our appreciation that there are
various sources of energy for us to use but using energy sources that we have
today wisely and not in wasteful ways to make sure that these energy sources
are still around for future generations to use.
We
should use and manage energy sources carefully. For example, we can:
1.
practice car-pooling or use
public transport
2.
switch off electrical
appliances when they are not in use
3.
turn off water taps when they
are not in use
4.
practice recycling of materials
5.
practice reuse of materials
6.
put emphasis on the use of
renewable energy sources
7.
recycle and reuse materials
8.
develop more efficient engines
that use less energy to operate
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