Waves of Energy
Energy often moves. Energy can be carried from one
place to another place by waves, electric currents, sound waves, and moving
objects. Energy can move through air, water, wires, and even our bodies.
Light is a kind of energy that moves from the sun to the Earth. Sound is
another kind of energy that moves from our mouths to the ears of people when we
Kinds of Waves
Energy moves through air, water and also our bodies.
The wind moving over water makes waves on its surface. Sometimes the waves are
small at other times they are big enough to toss a boat about.
You may also have experienced making your own waves in a bathtub as you move
around. Waves move in the form of high and low curves. Some other waves are like a coiled spring in a toy.
Energy often moves. Light and sound are two forms of energy, which move in
the form of waves. Light waves move as up and down waves. Sound waves move as
back and forth waves like a coiled spring toy.
Sound is a kind of energy that travels in waves. Think
of the sounds you hear every day, like the voice of a friend, the jingle of a
bell, the buzz of an insect, and the song on a radio. All these sounds seem
different but travel in waves. When an object begins to vibrate, the air around
the object vibrates too. Waves of the vibrating object reach our ears and our
brains interpret the sound. As the storm is coming towards you, you would
probably see the lightning before you hear the thunder. This shows that light
travels faster than sound.
Light is also a form of energy. It helps us to see
things around. It comes from several sources. But sun is the most important
source of light. In the absence of the sunlight we use candles and lamps. Light
has something in common with water waves. When you throw a pebble into a pond,
ripples move away from where the pebble hit. In a similar manner light waves
move away from a light source. Light waves travel until they hit an object and
bounce off, so that we can see the object. Light waves move too fast for us to
see them. They move at a rate of 300,000 kms /sec. Light travels through air,
space and clear materials like glass and water.
Energy can move as electricity
Light is another form of energy,
which travels in waves. Electricity is produced in energy companies and sent to
our homes. This can be utilized by plugging something into a socket. This energy
can be easily changed into many forms. It can be used to start a car, light a
lamp, to turn a fan, or to make your favorite toy car move.
Energy can move as heat
We generally say, it is very hot outside or
my soup is cold. You know what hot and cold feel like. Do you know what causes
this? It is heat. Every atom or particle in matter has energy. The total energy
of moving atoms in matter is called thermal energy. A cup of something that is
hot has more thermal energy than a same cup of something that is cold. The
movement of thermal energy from one place to another is called as heat. There
are many ways of producing thermal energy. Burning a fuel, lighting a gas stove
or by rubbing your palms together.
Different forms of Energy
Hydroelectric energy is created by harnessing
the power of water. Energy comes in two forms: potential energy and kinetic
energy. Potential energy is stored inside something such as oil, gas or other
fuels. Anything high above the ground also has potential energy since gravity
will cause it to fall. Kinetic energy is within something that is moving.
This conversion of energy is at the heart of all sources of energy, including
hydroelectric power. In hydroelectric energy, electricity is created from the
potential energy stored in water by dams or similar structures. These dams hold
back water creating a significant height difference, creating potential energy
as a result of gravity. Hydroelectric energy also takes advantage of the
kinetic, or motion energy of water as it drops from the top of a dam to the
bottom, traveling through large turbines.
Wind generators are another form of renewable energy
sources. Wind generators use large turbines that look like the propeller of an
airplane. Strong winds blowing over the blades cause them to rotate creating
energy, which is converted into electricity.
Wind energy is clean, non-polluting and the fastest growing source of
electricity in the world. It is reliable and renewable.
Nuclear power already generates close to 20 percent
of the worlds energy. Nuclear power creates energy in a way similar to how the
Sun creates energy. Nuclear power plants use a process called "nuclear fission"
in which uranium atoms are slit, giving off protons, neutrons and tiny particles
of energy. This energy is captured and used to generate electricity.
One major concern about nuclear energy is the radioactive waste that is
created in the process. This waste is harmful to people and must be carefully
disposed off for safety reasons. Scientists are still trying to develop the
ability to create energy using a nuclear fusion process as used by the Sun.
Nuclear fusion should generate less radioactive waste.
Scientists are constantly trying to develop other
renewable forms of energy such as solar energy. Solar energy uses solar panels
to capture energy from the Sun's rays and convert it into electricity. Solar
energy constitutes only a very small part of the energy we consume.