Download What is sound , light and energy

2014
What is sound , light and energy
Elena Sofía Patiño Guajardo
28/04/2014
Index
What is sound ………………………………………1,2
What is energy …………………………………..3,6
What is sound ………………………………………….7
What is sound?
Is the consequence of changing air pressure over time.
All sounds are vibrations traveling through the air as sound
waves. Sound waves are caused by the vibrations of objects
and radiate outward from their source in all directions. A
vibrating object compresses the surrounding air molecules
(squeezing them closer together) and then rarefies them
(pulling them farther apart). Although the fluctuations in air
pressure travel outward from the object, the air molecules
themselves stay in the same average position. As sound
travels, it reflects off objects in its path, creating further
disturbances in the surrounding air. When these changes in
air pressure vibrate your eardrum, nerve signals are sent to
your brain and are interpreted as sound.
Sound is a form of energy, just like electricity and light.
Sound is made when air molecules vibrate and move in a
pattern called waves, or sound waves. Think of when you
clap your hands, or when you slam the car door shut. That
action produces sound waves, which travel to your ears and
then to your brain, which says, "I recognize that sound.
Sound is mechanical energy in the form of pressure
variances in an elastic medium. These pressure variances
propagate as waves from a vibrating source.
Sound is a vibration that propagates as a mechanical
wave of pressure and displacement, through
some medium (such as air or water).
Sometimes sound refers to only those vibrations
with frequencies that are within the range of hearing for
humans [1] or for a particular animal.
What is energy?
Energy is the capacity of a system to do work. That system
may be a jet, carrying hundreds of passengers across the
ocean. A baby’s body, growing bone cells. A kite, rising on
the wind. Or a wave of light crossing a space.
In moving or growing, each of these systems is doing work,
and using energy. Every living organism does work, and
needs energy from food or photosynthesis. Humans also
create machines that do work for them, and that derive
energy from fuels.
Some of the many forms that energy takes are:
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Mechanical energy, which includes
- Potential energy, stored in a system.
- Kinetic energy, from the movement of matter.
Radiant or solar energy, which comes from the light
and warmth of the sun.
Thermal energy, associated with the heat of an object.
Chemical energy, stored in the chemical bonds of
molecules.
Electrical energy, associated with the movement of
electrons.
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Electromagnetic energy, associated with light waves
(including radio waves, microwaves, x-rays, infrared
waves).
Mass (or nuclear) energy, found in the nuclear
structure of atoms.
One form of energy can be converted to another form. This
transfer is based on the law of conservation of energy—one
of the laws of thermodynamics.
Humans converted energy from one form to another when
they lit the first fire. By burning wood, they released the
chemical energy stored in the bonds of the wood molecules,
generating thermal energy, or heat. Other examples? A
battery generates electrons from chemical reactions, which
are used to make electrical energy. A toaster takes electrical
energy and converts it to heat. Your leg converts the
chemical energy stored in your muscles into kinetic energy
when you pedal a bicycle.
Sound is a form of kinetic energy. Molecules of air are
vibrated, causing them to move in wave patterns. When
these waves hit the eardrum, they make it vibrate too. This
vibration energy is turned into electrical energy impulses,
which your brain interprets as sound.
Many times, multiple conversions are involved. Consider
nuclear power generation. Atoms in the nuclear fuel are
split, releasing their nuclear (mass) energy and creating
thermal energy. This heat energy is, in turn, captured in the
form of steam and used to drive a turbine generator,
creating kinetic energy. And, finally, this kinetic energy spins
a magnetic field around a conductor, causing a current to
flow—creating electrical energy.
To measure energy, we use the "heating value" of the fuel,
which indicates how much of a certain fuel is converted to
how much heat. Common units of energy are the calorie
and Btu.
Physicists, who are scientists who study force, motion and
energy, say that energy is the ability to do work, and work is
moving something against a force, like gravity. There are a
lot of different kinds of energy in the universe, and that
energy can do different things.
Energy can be found in many things, and takes many forms.
There is a kind of energy called kinetic energy in objects that
are moving. There is something that scientists call potential
energy in objects at rest that will make them move if
resistance is removed.
Energy lights our cities, powers our vehicles, and runs
machinery in factories. It warms and cools our homes, cooks
our food, plays our music, and gives us pictures on
television.
Energy is defined as the ability or the
capacity to do work.
We use energy to do work and make all movements. When
we eat, our bodies transform the food into energy to do
work. When we run or walk or do some work, we ‘burn’
energy in our bodies. Cars, planes, trolleys, boats, and
machinery also transform energy into work. Work means
moving or lifting something, warming or lighting something.
There are many sources of energy that help to run the
various machines invented by
What is the light?
Light is part of the electromagnetic spectrum, which
ranges from radio waves to gamma rays.
Electromagnetic radiation waves, as their names
suggest are fluctuations of electric and magnetic fields,
which can transport energy from one location to
another. Visible light is not inherently different from the
other parts of the electromagnetic spectrum with the
exception that the human eye can detect visible waves.
Electromagnetic radiation can also be described in
terms of a stream of photons which are massless
particles each travelling with wavelike properties at the
speed of light. A photon is the smallest quantity
(quantum) of energy which can be transported and it
was the realization that light travelled in discrete
quanta that was the origins of Quantum Theory.
It is no accident that humans can ‘see’ light. The
detection of light is a very powerful tool for probing the
universe around us. As light interacts with matter it can
be become altered and by studying light that has
originated or interacted with matter, many of the
properties of that matter can be determined. It is
through the study of light that for example we can
understand the composition of the stars light years
away or watch the processes that occur in the living
cell as they happen