Transcript Energy - Clocke

ENERGY
ENERGY?
 Energy
 We
drives our world.
put it in our cars, food in
our stomachs, and batteries in
our toys because everything in
our world needs energy to
make it happen.
 Energy
makes our world
buzz with light, color,
sound, and motion.
 Without energy, life
would not be possiblenothing could grow,
move or feel and the
world would be a dark,
cold and lifeless place.
Where does it all come from?
 Most
of our energy
comes from the sun.
Where did the sun get all its
energy from?
 Scientists
believe it came from the Big
Bang
 No more energy has been created since
or will it ever be made in the future.
Energy is Everywhere

Everything in the
world involves energy
changing from one
form to another.



Water in a water
bottle.
Sneakers on your feet.
Muscles in your body.
How do we define ENERGY?
 Energy
can be defined as the ability
to do work.
 If
an object or organism does work (exerts
a force over a distance to move an object)
the object or organism uses energy.
How do we measure energy?
 Because
of the
direct connection
between energy and
work, energy is
measured in the
same unit as work:
joules ( J).
James Prescott Joule
Forms of Energy

Energy is recognized in seven forms all of
which a kinetic or potential
Thermal (heat)
 Mechanical (motion)
 Chemical
 Nuclear
 Electrical ( electricity, lighting)
 Radiant/ Electromagnetic (light, x-rays)
 Sound (Motion)

The Man Could Not Even Remember Snow!
Potential vs. Kinetic

All forms of energy fall
under two categories.

Potential energy is
stored energy.

Kinetic energy is
motion.
Potential vs. Kinetic

All forms of energy fall
under two categories.

Potential energy is stored
energy.

Kinetic energy is motion.

As a basketball player throws
the ball into the air, various
energy conversions take
place.
Ball slows down
Ball speeds up
Kinetic-Potential Energy
• Roller coasters work because of the energy that is
built into the system. Initially, the cars are pulled
mechanically up the tallest hill, giving them a great
deal of potential energy. From that point, the
conversion between potential and kinetic energy
powers the cars throughout the entire ride.
Radiant Energy

Electromagnetic energy that travels in
transverse waves.
Visible light
 X-rays
 Gamma rays
 Radio waves

Thermal Energy
The internal motion of the atoms is called
heat energy, because moving particles
produce heat.
 Heat energy can be produced by friction.
 The faster the molecules move, the more
heat energy is produced.
 Examples:

Friction
 Phase change

Sound

The movement of energy through objects or
substance in longitudinal waves
Chemical Energy
 Energy
stored in the bonds that
hold atoms together.
 When bonds are broken, energy is
released.
 Examples:



Digesting food…bonds are broken to release energy
for your body to store and use.
Sports… your body uses energy stored in your
muscles obtained from food.
Fire–a chemical change.
Nuclear Energy
Energy stored in the nucleus of an atom.
 Nuclear energy is the most concentrated form
of energy.

•When the nucleus splits
(fission), nuclear energy is
released in the form of heat
energy and light energy.
•Nuclear energy is also
released when nuclei collide
at high speeds and join (fuse
– “fusion”)
Nuclear Energy
The sun’s energy is
produced from a
nuclear fusion
reaction in which
hydrogen nuclei fuse
to form helium
nuclei.
Stored Mechanical Energy

Energy stored in objects or substances by
the application of force.
Gravitational Potential Energy

The energy of place or
position.

A waterfall, a
suspension bridge, and
a falling snowflake all
have gravitational
potential energy.
Energy Conversion

All forms of energy can be changed from
one form to another. Changes in the form
of energy are called energy conversions.
The sun’s energy through solar cells can be
converted directly into electricity.
 Green plants convert the sun’s energy
(electromagnetic) into starches and sugars
(chemical energy).

Other energy conversions
In an electric motor, electromagnetic energy is
converted to mechanical energy.
 In a battery, chemical energy is converted into
electromagnetic energy.
 The mechanical energy of a waterfall is
converted to electrical energy in a generator.

Energy Conversions

In an automobile
engine, fuel is burned
to convert chemical
energy into heat
energy. The heat energy
is then changed into
mechanical energy.
The Law of Conservation of Energy

Energy can be neither created nor destroyed
by ordinary means.

It can only be converted from one form to
another.