Energy and Energy Sources

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Energy and Energy Sources

• IPC

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I. The Nature of Energy

• A. Energy is the ability to cause change.
• 1. Kinetic energy energy in the form of motion.
• a. The amount of kinetic energy an object has
  depends on its mass and its velocity.
• b. Kinetic Energy mv2
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• c. Joules- the SI unit to measure energy.
• 2. Potential Energy - energy stored in a
  motionless object, giving it the potential to
  cause change.

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I. The Nature of Energy

• A. Energy is the ability to cause change.
• 3. Elastic potential energy - energy stored by
  things that stretch or compress.
• 4. Chemical potential energy energy stored in
  chemical bonds between atoms

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I. The Nature of Energy

• A. Energy is the ability to cause change.
• 5. Gravitational potential energy energy
  stored by things that are above the Earth.
• a. the amount of GPE and object has depends on
  its mass, the acceleration due to gravity, and
  its height above ground.
• b. GPE mass(kg) x 9.8 m/s2 x height(m)

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II. Conservation of Energy

• A. Energy Conversions energy changing from one
  form to another.
• 1. Fuel store energy in the form of chemical
  potential energy.
• 2. Mechanical energy the total amount of
  potential and kinetic energy in a system.

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II. Conservation of Energy

• B. Law of Conservation of Energy Energy may
  change from one form to another, but the total
  amount of energy never changes.
• 1. Example as a swing moves back and forth, its
  energy continually converts from kinetic to
  potential and back.
• 2. If the energy of the swing decreases, then
  the energy of some other object must increase by
  an equal amount.
• 3. Friction converts on the mechanical energy
  into thermal energy.

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II. Conservation of Energy

• C. Converting mass to energy you must think of
  mass as energy when discussing nuclear reactions.
  The total amount of mass and energy is conserved.
• 1. Nuclear fusion two nuclei are fused together
  takes place in the sun.
• 2. Nuclear fission two nuclei are broken apart.

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II. Conservation of Energy

• D. Conservation of Energy in your body.
• 1. Chemical potential energy from food that is
  stored in your body is used to fuel the processes
  that keep you alive.
• 2. The food calorie is used to measure how much
  energy you get from various foods.
• 3. One calorie is equal to 4,180 J.

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III. Energy Sources Fossil Fuels

• A. Energy can not be created nor destroyed
  according to the law of conservation of energy,
  but energy can be converted from one form to
  another.
• B. Fossil fuels formed from decaying remains of
  ancient plants and animals.
• 1. Burning fossil fuels converts energy from
  chemical bonds to light and heat.
• 2. Chemical energy in fossil fuels is more
  concentrated than in other fuels such as wood.

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III. Energy Sources Fossil Fuels

• C. Petroleum- thick, greenish-brown, highly
  flammable liquid formed by decayed ancient
  organisms
• 1. A process called fractional distillation
  separates the compounds in petroleum.
• 2. Petroleum is used for plastics, synthetic
  fabrics, and other products in addition to its
  use as a fuel.

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III. Energy Sources Fossil Fuels

• D. Natural gas is also a product of ancient
  organisms.
• 1. It contains more energy per kilogram than
  petroleum or coal.
• 2. It burns more cleanly than other fossil fuels.
• 3. It provides about one-fourth of the energy
  consumed in the United States.

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III. Energy Sources Fossil Fuels

• E. Coal a solid fossil fuel found underground.
• 1. It produces more pollution when burned than
  natural gas or petroleum.
• 2. It provides about one-fourth of the energy
  produced in the United States.
• 3. About 90 percent of coal burned in the United
  States is used to produce electricity.

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III. Energy Sources Fossil Fuels

• F. Electricity is generated when fossil fuels are
  burned.
• 1. The burned fuel releases thermal energy.
• 2. The thermal energy produces high pressure
  steam.
• 3. The steam spins a turbine.
• 4. The spinning turbine produces an electric
  current.
• 5. The electric current is transmitted through
  power lines to consumers.

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III. Energy Sources Fossil Fuels

• G. Only about 35 of the energy in fossil fuel
  reaches consumers since some energy is lost in
  every stage of the process.

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III. Energy Sources Fossil Fuels

• H. Fossil fuel have some undesirable side
  effects.
• 1. Fossil fuel pollute the environment and
  increase carbon monoxide in the atmosphere.
• 2. Mining coal can cause health problems for
  miners.

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III. Energy Sources Fossil Fuels

• I. Fossil fuels are nonrenewable resources, so it
  is important to not waste energy.

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IV. Nuclear Energy

• A. About 20 of the electricity in the U.S. come
  from nuclear power plants.
• B. Nuclear reactors contain a fuel, rods to
  control nuclear reactions, and a cooling system.
• 1. Heat is produced by nuclear fission energy
  is released when U-235 nuclei split in two after
  being struck by a neutron.
• 2. Special rods absorb excess neutrons to prevent
  dangerous chain reactions

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IV. Nuclear Energy

• C. Nuclear Power plants use the heat of nuclear
  fission to produce steam.
• 1. The steam drives a turbine.
• 2. The Turbine rotates an electric generator.

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IV. Nuclear Energy

• D. Nuclear power plants produce nuclear
  wasteradioactive by-products from radioactive
  materials.
• 1. Low-level wastes contain only a small amount
  of radioactive material.
• 2.High-level wastes must be disposed of
  extremely carefully because they will remain
  radioactive for tens of thousands of years.

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IV. Nuclear Energy

• E. Nuclear Fusionthe joining together of
  nucleiis not a practical energy source due to
  the high temperature fusion requires.

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V. Renewable Energy Sources

• A. A renewable resource can be replaced as
  quickly as it is used.

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V. Renewable Energy Sources

• B. Solar energy is converted into electricity by
  a photovoltaic cell or solar cell.
• 1. A solar cell converts only 15 to 20 percent
  of the suns energy into electricity.
• 2. Energy produced by solar cells is more
  expensive than energy produced with fossil fuels.
• 3. Energy from solar cells must be stored in
  batteries when the Sun is not shining.

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V. Renewable Energy Sources

• C. Hydroelectricity is produced by moving water
  it is about twice as efficient as fossil fuels or
  nuclear power.

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V. Renewable Energy Sources

• D. Tidal energy uses moving water, but it can
  only be used in places where high and low tides
  are different enough.

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V. Renewable Energy Sources

• E. Windmills can be used to generate electricity,
  but are useful only when the wind blows
  consistently.

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V. Renewable Energy Sources

• F. Geothermal energythermal energy contained in
  hot magma limited to areas where magma is close
  to the surface.

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V. Renewable Energy Sources

• G. Alternative fuels include hydrogen gas and
  biomassrenewable organic matter such as wood or
  animal manure.