Download What is Energy? - Plain Local Schools

The Nature of Energy
Benchmarks
Standard III: Physical Sciences
E. Demonstrate that energy can be considered to be either kinetic
(motion) or potential (stored).
F. Explain how energy may change form of be redistributed but
the total quantity of energy is conserved.
G. Demonstrate that waves have energy and waves can transfer
energy when they interact with matter.
H. Trace the historical development of scientific theories and
ideas, and describe emerging issues in the study of physical
sciences.
What is Energy?
Energy - ability to do work
 Work - force moves an object a distance
W = Fd
units are Joules ( J ) for energy
units for force are Newtons ( N )
units for distance are meters ( m )
*** A Joule can also be considered a “Nm”

-Complete Calculating Work Practice sheet
States of Energy

Potential Energy - stored energy, based on
position of chemical composition
Gravitational Potential Energy
GPE = mass x gravity x height
GPE = mgh
--> units Joules
m=mass (g)

g=gravity (9.8 m/s2)
h=height (m)
A 50kg rock is on the edge of a 20m cliff,
what is its GPE?
GPE = m x g x h
= 50kg x 9.8m/s2 x 20m = 9800J
States of Energy the Sequel

Kinetic Energy - energy of motion, based on mass
and velocity of object
Kinetic Energy
KE = 1/2 mv2
m=mass (g)

--> units Joules
v=velocity (m/s)
A 1000kg car is traveling 40m/s, what is its KE?
KE = 1/2mv2
= 1/2 x 100kg x (40m/s)2
= 1/2 x 100kg x 1600m2/s2 = 80,000J
-Complete Calculating Power and
Potential/Kinetic Energy worksheets
Forms of Energy
1.
2.
3.
Six Forms of Energy
Mechanical - moving objects perform work
Ex: wheels turning, hammer hitting a nail,
sound
Chemical - energy stored in the molecules
of substances
Ex: coal, oil, nature gas, food
Nuclear Energy - stored in nucleus of atom
Ex: Uranium used for fission
Forms of Energy
Six Forms of Energy
4. Heat - energy caused by molecular motion
Ex: Rubbing hands together, lighting a
match
5. Electrical - flow of electrons through a
conductor
Ex: computers, televisions, generators
6. Light - radiant energy that moves in waves
Ex: sun, light bulbs, electromagnetic
energy
Conservation of Energy and
Matter
The Law of Conservation of Energy
energy can be neither created nor
destroyed, only transformed
The Law of Conservation of Matter
matter can be neither created nor destroyed,
only rearranged
*The total amount of matter and energy in the
always remains constant in the universe
Types of Energy

RENEWABLE
–
–
Solar – energy harnessed from the sun
Hydroelectric– energy harnessed from the Potential
energy of water
–
Biomass– energy harnessed agricultural and animal
waste products
–
–
Wind– energy harnessed from the wind
Geothermal– energy harnessed from heat under
earth’s crust
 http://library.thinkquest.org/20331/types/

NONRENEWABLE
–
Fossil fuels: energy from natural gas, petroleum and
coal
–
Nuclear: energy from fission and fusion
–
What are the advantages and disadvantages of each?

Energy brochure: what type of energy do you think Ohio should
consider to help our energy demands and decrease our dependence
on coal. http://www.puco.ohio.gov/puco/index.cfm/consumer-information/consumertopics/where-does-ohioe28099s-electricity-come-from/
Energy Transformations

Energy can transform from one form to
another
 Ex: A black car absorbs light energy from the
sun and transforms it to heat energy to warm
up the car
 ***During many energy transformations heat
is produced as an unwanted product
 Ex: Motors loose a great deal of energy to
unwanted heat energy
-%efficiency worksheet
Nuclear Energy

The three categories of
forces are:
 Gravitational Forces
 Electromagnetic Forces
 Nuclear Forces
1. Strong Force
2. Weak Force
*Nuclear forces are the
strongest types
Fission




Fission is the process of
splitting the nucleus of an
atom into two lighter
weight nuclei producing
large amounts of energy
Bombarding Ur-235 or Pu
with a neutron causes it
to split into Kr and Ba,
and continues as a chain
reaction
Used in nuclear power
plants and weapons
Produces nuclear waste
Fusion

Fusion is the process of
combining two or more
lighter weight nuclei to
form a heavier nucleus
releasing large amounts
of energy
 Hydrogen isotopes are
converted to Helium
under extreme
temperatures
 Does not produce waste
products, has abundant
resources (Hydrogen),
and is safer than fission
Nuclear Reactor



Nuclear reactors control
the fission process by
using the heat produced
to produce steam that
turns a turbine to produce
electricity
The moderator and
control rods slow the
speed of the fission
reaction by absorbing
neutrons
There is lead shielding
around the core to protect
against radiation
Nuclear Incidents

Meltdowns:
–
–
Chernobyl in Russia
Recent Tsunami in Japan
Partial Meltdowns:
-3 mile Island (1979, Harrisburg, Pa)
-experimental partial meltdowns:
Fermi 1 (1966), Borax-1 (1954)