Sources of Energy

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Sources of Energy

• Ms. Angels 3rd Grade
• Greenbriar West Elementary
• 2004-2005

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Teaching Strategy

• Lecture
• Reinforce terms from handout provided by GBW
• Interactive use handout as framework, not many
  answers on the sheets
• marks the sheets the students will
  get
• Lab
• Provide handout for lab groups to use
• Reinforce skills in observation, data collecting,
  data plotting, and making conclusions

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Topics

• Energy
• Mass and Force
• Potential and Kinetic Energy
• Electricity
• Renewable Energy Sources
• Nonrenewable Energy Sources

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Energy

• Examine mass, force, and work as an introduction
  to energy and power

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Mass

• What is mass?
• Does a party balloon have more mass than a candy
  bar?
• How do you figure out an objects mass?

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Mass

• What is mass?
• Matter or stuff
• Does a party balloon have more mass than a candy
  bar?
• Bring in one of each contrast size vs mass
• How do you figure out an objects mass?
• Weigh it but is mass the same thing as weight?
  No, will talk about this in a moment mass of
  something is the same no matter what but its
  weight varies

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Force Key Points

• What is a force?
• Why does gravity exert a force on you?
• If an object is not moving does that mean that
  there are no forces on it?

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Force Key Points Answers

• What is a force?
• Something that pushes or pulls you
• Why does gravity exert a force on you?
• Two objects with mass attract each other
• If an object is not moving does that mean that
  there are no forces on it?
• It may but it probably means that the forces
  acting on an object cancel out

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Forces
The man is standing still. Are there any
forces on the man? If so, draw them.
floor
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Forces
The force due to gravity is the same in size, but
opposite in direction, to the force by the
floor!!!!
Gravity
Floor
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Gravitational Force - Questions

• So what causes a gravitational force?
• Is there a gravitational force on the moon?
• Is it larger or smaller than the gravitational
  force on the Earth?

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Gravitational Force - Answer

• So what causes a gravitational force?
• Two objects are attracted to each other

Object 1 (has mass)
F1
F1 F2
F2
Object 2 (has mass)
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Gravitational Force

• Gravitational force keeps us stuck to the
  Earth!!!
• We actually pull on the Earth but the Earth is
  too big to move!!!

Person
How much you weigh depends on your mass and the
mass of the planet you are on.
F
Fperson Fearth
F
Earth
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Gravitational Force - Questions

• Is there a gravitational force on a person
  standing on the moon?
• Is it larger or smaller than the gravitational
  force on the Earth?
• Why?

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Gravitational Force -Answers

• Is there a gravitational force on the moon?
• Is it larger or smaller than the gravitational
  force on the Earth? yes
• The gravitational force is smaller on the moon
  1/6 of the Earth.
• Why?
• The moon is smaller (1/6th the mass) than the
  Earth.

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How the Moon Causes Tides

• Since the water in the oceans are liquid they are
  pulled out of shape by the moons gravitational
  force
• Causes water level to rise thus creating tides
  (i.e. water seemingly getting deeper and
  shallower for no apparent reason)

Earth
Water bulging up
Moon
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Weight vs Mass

• Weight is a force W m g
• m mass and
• g acceleration due to gravity 9.81 m/s2

PLOT THE DATA!!
180
m (kg) W (N)
10 98
5 49
12 118
5 52
18 177
5 47
8 78
160
140
120
100
Weight, N
80
60
40
20
0
0 2 4 6 8 10 12 14 16 18 20
Mass, kg
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Weight vs Mass

• The slope of the plot is g 9.81 m/s2

180
X
m (kg) W (N)
10 98
5 49
12 118
5 52
18 177
5 47
8 78
160
140
120
X
100
X
Weight, N
80
X
60
X
X
X
40
20
0
0 2 4 6 8 10 12 14 16 18 20
Mass, kg
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Break
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Work

• Review Force is a push or a pull
• Exerting a force over a distance is WORK
• For example, pushing the desk across the room is
  a lot of work

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Potential and Kinetic Energy Key Facts

• What is energy?
• What is potential energy?
• What is kinetic energy?

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Potential and Kinetic Energy Key Facts

• What is energy?
• Ability to do work
• Potential energy stored energy
• How can we store energy?
• Kinetic energy energy of movement
• How is potential energy converted into kinetic
  energy?

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Potential Energy
Does the ballhave any storedenergy here?
Does the ballhave any storedenergy here?
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Potential Energy
Does the ballhave any storedenergy here?
Does the ballhave any storedenergy here?
YES, we moved the ballagainst gravity (did work)
NO
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Potential Energy
What happens when we let go of the ball? If the
ball is to move show the direction of the
ball. Label the forces on the ball!!!!
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Potential/Kinetic Energy
What happens when we let go of the ball? It
starts to fall has kinetic energy Convert
potential into kinetic energy If the ball is to
move show the direction of the ball. Label the
forces on the ball!!!! Gravity is larger force
than air resistance
Gravity
velocity
Air resistance
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Quick Review of Science Facts

• Force is a push or pull
• Work is exerting a force over a distance
• Energy is the ability to do work
• Power is energy being used over a period of time

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Introduction to Electricity
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Electricity

• Electricity is a form of energy that starts with
   atoms.
• Atoms are too small to see, but they make up
  everything around us.
• An atom has three tiny parts  protons,
   neutrons, and  electrons. The center of the atom
  has at least one proton and one neutron. At least
  one electron travels around the center of the
  atom at great speed.
• Electricity is created by forcing electrons to
  flow from atom to atom.
• What kind of energy is this?

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Electricity - Answers

• Electricity is a form of energy that starts with
   atoms.
• Atoms are too small to see, but they make up
  everything around us.
• An atom has three tiny parts  protons,
   neutrons, and  electrons. The center of the atom
  has at least one proton and one neutron. At least
  one electron travels around the center of the
  atom at great speed.
• Electricity is created by forcing electrons to
  flow from atom to atom.
• What kind of energy is this?Kinetic energy
  the electrons are moving

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How Electricity is Generated

• Most electricity used in the United States is
  produced at  power plants.
• Various energy sources are used to turn
   turbines.
• The spinning turbine shafts turn electromagnets
  that are surrounded by heavy coils of copper wire
  inside generators.
• This creates a magnetic field, which causes the
  electrons in the copper wire to move from atom to
  atom.

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Nonrenewable Energy Sources
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Renewable vs Non-Renewable?

• What is a renewable energy source?
• What is a non-renewable energy source?

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Renewable vs Non-Renewable?

• What is a renewable energy source?
• You can make more of it
• What is a non-renewable energy source?
• There is a limited amount of it and you cannot
  make more of it

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Break
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Non-Renewable Energy Sources

• Give some examples of nonrenewable energy sources

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Fossil Fuels

• The majority of electricity used in the United
  States is generated from power plants that burn
  fossil fuels (coal, oil, and natural gas).
• Why do we call these fossil fuels?
• Why does this make them nonrenewable?
• When the fossil fuels are burned they heat water
  and make steam.
• The highly pressurized steam is directed at the
  blades of turbines to make them spin.
• What type of energy conversion is this process?

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Fossil Fuels

• The majority of electricity used in the United
  States is generated from power plants that burn
  fossil fuels (coal, oil, and natural gas).
• Why do we call these fossil fuels?
• Oil, coal, and gas are formed by many tiny
  organisms being compressed (high heat and
  pressure) by layers of sand and rock over the
  years
• Why does this make them nonrenewable?
• It takes millions of years to create fossil fuels
• When the fossil fuels are burned they heat water
  and make steam.
• The highly pressurized steam is directed at the
  blades of turbines to make them spin.
• What type of energy conversion is this process?
• Potential into kinetic and kinetic into kinetic

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Nuclear Energy

• Nuclear power plants use the heat from splitting
  atoms to convert water into the steam that turns
  turbines.
• These plants rely on uranium, a type of metal
  that must be mined from the ground and specially
  processed.
• Fuel rods containing uranium are placed next to
  each other in a machine called a nuclear reactor.
  
• The reactor causes the uranium atoms to split and
  in so doing, they release a tremendous amount of
  heat.

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Renewable Energy Sources
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Renewable Energy Sources

• Give some examples of renewable energy sources
  be creative!!!

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Solar Energy

• Solar energy is generated without a turbine or
  electromagnet. Special panels of photovoltaic
  cells capture light from the sun and convert it
  directly into electricity. The electricity is
  stored in a battery.
• What type of energy conversion process is
  happening here?

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Solar Energy

• Solar energy is generated without a turbine or
  electromagnet. Special panels of photovoltaic
  cells capture light from the sun and convert it
  directly into electricity. The electricity is
  stored in a battery.
• What type of energy conversion process is
  happening here?
• Kinetic to electrical

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Wood

• Burn wood from trees to produce heat to create
  steam by heating water which in turn power
  turbines
• Wood is renewable only if trees are replanted and
  grown as quickly as they are used
• Why is wood not normally used to make
  electricity?

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Wood

• Burn wood from trees to produce heat to create
  steam by heating water which in turn power
  turbines
• Wood is renewable only if trees are replanted and
  grown as quickly as they are used
• Why is word not used to make electricity?Doesn
  t create much heat (per lb) and is very messy

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Grain Fuel - Ethanol

• Distill grain into a liquid fuel called ethanol
  that can be used for cars and power plants
• Renewable source is simply grain (e.g. wheat,
  barley, etc like those used in bread) can
  always grow more
• Over 2 million cars per year in the USA already
  are set up to run on E85 (85 ethanol and 15
  gasoline)

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(No Transcript)
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Geothermal Power

• Steam (or hot water converted to steam) from
  under the ground is used to turn turbines.
• Usually from geysers or hot springs
• Why might this form of energy not be used very
  much?

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Geothermal Power

• Steam (or hot water converted to steam) from
  under the ground is used to turn turbines.
• Usually from geysers or hot springs
• Why might this form of energy not be used very
  much?Not many hot springs and difficult to
  pipe steam or hot water

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Hydropower

• Hydroelectric plants use the power of falling
  water to turn the turbines that help generate
  electricity. Water stored behind a dam is
  released and directed through special tubes to
  flow against the blades of turbines and make them
  turn.
• What type of energy conversion is taking
  place?
• Hydropower provides about 10 percent of the
  electricity generated in the United States.
• The most famous hydroelectric facility in the
  country is Hoover Dam.

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Wind Power

• Wind is usually created by uneven heating of the
  earth
• The force of the wind is used to spin many small
  turbines.
• Most wind power is produced from wind farms
  large groups of turbines located in consistently
  windy locations.
• Why might wind power be difficult to generate?

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Wind Power

• Wind is usually created by uneven heating of the
  earth
• The force of the wind is used to spin many small
  turbines.
• Most wind power is produced from wind farms
  large groups of turbines located in consistently
  windy locations.
• Why might wind power be difficult to
  generate?Some days it is not windy and the
  windmills or turbines take up a lot of room

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Wind and water power experiment(split class into
two teams)

• Water
• Pour a gallon of water each day into hydropower
  plant
• Count turns of the wheel
• Plot the data
• Reuse water
• Make observations

• Wind
• Take wind power plant outside each day for one
  hour
• Count turns of the gear
• Plot the data
• Make observations

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Wind and Water Plots
Use W for wind and H for water (hydro)
10 8 6 4 2 0
Turns
1 2 3 4 5 6 7 8 9
10
Day
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Wind and Water Plots(possible example results)
Use W for wind and H for water (hydro)
W
10 8 6 4 2 0
W
Turns
W
W
H
H
W
W
H
H
H
H
H
H
H
W
W
H
W
W
1 2 3 4 5 6 7 8 9
10
Day
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Experiment Summary

• What would be the best way to produce energy
  water or wind?

Energy Source Good About It Bad About It
Water
Wind
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Experiment, Plot, Observe And Conclude
SCIENCE EXPERT
Ms Angels Class