Transcript Energy Ch. 13 pg. 442

Energy
Ch. 13
pg. 442
Objectives
• Describe how energy, work, and
power are related.
• Name and describe the two
basic kinds of energy.
What is Matter?
• Anything that has mass and
takes up space. Everything
has matter.
What is Energy?
• The ability to do work or cause change
• Particle movement = Energy
• The more movement, the more energy,
the more heat that is generated.
Work and Energy
• REMEMBER
• Work = Force x distance
• So when work is done on an
object some of its energy is
transferred to the other object.
Energy and Power
• REMEMBER
• Power = Work / time
• Power is the rate at which
energy is transferred =
work
Calculate power and energy
• Power = Energy transferred(work)
time
Two kinds of Energy
1. Kinetic Energy
2. Potential Energy
All types of energy falls under
one of these forms
Kinetic Energy
• Any object in motion is
considered to have kinetic
energy.
• Kinetic comes from the Greek
word kinetos, which means
“moving”
Factors that affect kinetic energy
• Friction
• Velocity of the object in motion
• Mass of the object
Calculate Kinetic Energy (KE)
•
•
•
•
Kinetic Energy (Joule)
Mass (g or kg)
Velocity=speed (m/s)
Kinetic Energy = ½ x mass x velocity2
Potential Energy (PE)
• Stored energy that results from the
position or shape of the object.
• Objects that have the potential to
move/do work.
• ALL objects not moving have PE.
• PE is related to an objects height.
Gravitational Potential Energy
(GPE)
• This is the energy related to an
object’s height.
• The higher the object, the more PE
the object has.
• GPE = Weight(N) x Height(m)
Elastic Potential Energy
(EPE)
• Stretching or compressing
of objects
• Example; rubber band,
bow and arrow
Forms of Energy
Ch. 13-2
Objectives
• How can you determine an
object’s mechanical energy?
• What are some forms of energy
associated with the particles
that make up an object?
Forms of Energy
•
•
•
•
•
•
Mechanical energy
Thermal energy
Electrical energy
Chemical energy
Nuclear energy
Electromagnetic energy
Mechanical Energy
• Energy associated with motion.
• Mechanical Energy = PE + KE
Forms of Energy
• Deal with particles that make up
the objects.
• Types of particle motion
Thermal Energy
• Heat energy stimulated from the
motion of particles within matter.
• The faster the particles move the
more heat is generated
Electrical Energy
• The energy of electrical charges,
lightning
Chemical Energy
• The potential energy stored in the
chemical bonds that hold chemical
compounds together.
• Chemical energy is stored in food
we eat and in turn is changed into
mechanical energy.
Nuclear Energy
• The energy stored in the nucleus of an
atom.
• The sun goes through nuclear fusion
constantly combining hydrogen atoms
with helium atoms. This results in the
light and heat we see.
• Fission is the splitting of an atom
creating nuclear bombs.
Electromagnetic Energy
• Energy that travels in waves.
• X-rays, microwaves, ultraviolet
(UV), infrared radiation, and radio
waves.
Energy Transformation
and Conservation
• How are different forms of energy
related?
• What is a common energy
transformation?
• What is the law of conservation of
energy?
Energy Transformations
• A change from one form of energy
to another form to get work done.
• Ex. Chemical(energy in food) to
Mechanical(energy of motion to
move your muscles)
Energy Conservation
• Law of Conservation of Energy states
that when one form of energy is
transformed to another, no energy is
destroyed in the process.
Energy cannot be created nor
destroyed it just changes
form.
How can energy be created?
• By destroying matter.
• Ex. If I burn a log to ash. I am destroying
matter, but creating many types of energy.
• Chemical
• Thermal
• Light
Questions/Review
1. What is the relationship between different
forms of energy?
2. When you turn a toaster on, what happens
to the electrical energy?
3. Describe the energy transformations that
happen whey you strike a match. List
them in order in which they occur.
1. They can be transformed into
other forms of energy.
2. Electrical energy is transformed
to thermal energy.
3. First, striking the match
mechanical energy to thermal
energy. Thermal energy causes
particles to release into chemical
energy. Chemical energy is
transformed to thermal and
electromagnetic energy.
Energy Sources
• Renewable
• Nonrenewable
Renewable Energy
• Are sources that can be replenished in
a short period of time.
1. Water (hydropower)
2. Wind
3. Solar
4. Geothermal (heat from the Earth’s
center)
5. Biomass – wood and waste porducts
Hydroelectric Power
Wind Power
Biomass
Geothermal Energy
Solar Power
What role does renewable
energy play in the U.S.?
• Over half of renewable energy
goes to producing electricity.
Nonrenewable Resources
•
•
1.
2.
3.
4.
Sources of energy not able to be renewed
or replenished.
Fossil Fuels
Oil and petroleum products (gasoline,
diesel fuel, and propane)
Natural gas
Coal
Uranium (nuclear energy)