Transcript What is Energy?

THE SCIENCE OF
ENERGY
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1. What is Energy?
The ability to make things
move or do work
Can you make things
move?
Then you have energy!
2. The Law of Conservation of
Energy-”energy is neither
created or destroyed”
The energy we use is stored in
different forms. We do not use
it up, it is just changed or
transformed into other forms of
energy.
3. Energy Efficiency
The amount of useful
energy obtained from a
system
Energy Transformation
Demo
Copy this Chart in your journal
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Ending
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Demo Energy Flow
• Thermal energy from body in motion
• Body got energy from chemical energy
stored in food
• Chemical energy in food came from
transforming radiant energy from the Sun
through photosynthesis
• Radiant energy was created by nuclear
energy of fission
Ultimately all energy comes
from nuclear energy
*5 Main Things Energy can
help us do…….
1.
2.
3.
4.
make things move
make heat
make light
make technology work (run
electrical devices)
5. make things grow
Can you think of an example of each?
**2 Major forms of energy
1. Potential-stored energy;
energy of position;
energy at rest
•
•
Depends on height and
weight
Can be calculated with the
formula: PE= W x H
1a. Chemical Energy…
(potential energy)
• is the energy stored in the bonds
of atoms and molecules.
• Examples: Biomass, petroleum,
natural gas, propane, and coal
• Can be released by chemical
reactions like burning wood
1b. Nuclear Energy
(potential energy)
• Holds protons and neutrons
together in an atom’s nucleus
• Powers the sun and nuclear power
plants
• The energy in the nucleus of a
uranium atom is an example.
1c. STORED MECHANICAL
ENERGY (potential energy)
•is energy stored in objects by the
application of force.
•Examples: Compressed
springs and stretched rubber
bands
1d. Gravitational Energy
(potential energy)
•is the energy of
place or position.
•Water in a
reservoir behind
a hydropower
dam is an
example.
2. Kinetic-energy of motion
(waves, atoms,
molecules, substances)
*can be affected by
mass and speed
* can be calculated:
2
KE=1/2mv
2a. Electrical Energy
(kinetic)
• The movement of
electrons through matter
• Electricity and lightning is
a form of electrical
energy
2b. Thermal/Heat
Energy (kinetic)
• The random motion, or
vibration, of atoms in matter
• Internal energy of substances
• The faster the atoms vibrate
the more heat energy they
have
• Example: geothermal
2c. Radiant/Light
Energy
• The energy carried by light
in the form of
electromagnetic (transverseside to side) waves
• All lights and the rays of
the Sun (Solar) are
examples
2e. Mechanical/Motion
Energy (kinetic)
• The energy of moving
things
• When you ride a bike you
use mechanical energy
• Wind and hydropower are
some other examples
2f. Sound Energy
• Vibrates air molecules
• The air molecules move tiny
bones in your ear
• The message of sound then
moves to your brain
• Can also vibrate objects in
longitudinal waves
Energy can be changed
from one form to
another
• Chemical energy in
gasoline is changed to
heat energy and then to
mechanical energy in a
car