Energy and Energy Resources

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Energy and Energy Resources
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Energy

• Defined as the ability to do work or the ability
  to cause change.

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Two types of energy

• Kinetic energy- energy of motion anything that
  moves has kinetic energy, cars, balls, and even
  atoms.
• Potential energy- stored energy sometimes called
  energy of position, anything not moving has
  potential energy

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Swinging Pendulum
P.E. is greatest here, K.E. 0
P.E. is greatest here, K.E. 0
Kinetic energy is greatest here, P.E. 0
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Kinetic energy

• The amount of kinetic energy an object has
  depends on two things
• 1. mass
• 2. velocity
• K.E. 1/2mv
• ½ (mass X velocity squared)

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Potential Energy

• This is the energy that something that is not
  moving has the potential of having.
• Potential energy depends on
• 1. mass
• 2. position (height and gravity)
• P.E. mgh (mass X gravity X height)

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Forms of energy

• Thermal
• Chemical
• Light
• Sound
• Electrical
• Nuclear
• All forms of energy have kinetic and/or
  potential energy.

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Thermal energy

• Heat energy- all objects have thermal energy it
  increases as temperature increases.
• Which has more thermal energy? Why?

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Chemical Energy

• Energy stored in chemical bonds includes the
  food we eat.

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Light energy

• Form of energy that we see.

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Sound energy

• Energy caused by vibrations some of these
  vibrations we can hear.

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Electrical energy

• Energy that is carried by an electric current (a
  path that electrons follow).

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Nuclear Energy

• Energy from the nucleus of an atom

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Energy Transformations

• Change from one form of energy to another.
• Always produces thermal energy (heat).

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Examples of energy transformations

• Photosynthesis (light to chemical)
• Digestion of food (chemical to mechanical)
• Burning of fuel (chemical to mechanical and
  thermal)
• Electrical to light and thermal (light bulb)

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Law of Conservation of Energy

• States that energy cannot be created or
  destroyed, only transferred or changed from one
  form to another.

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Kinetic and Potential Energy

• Kinetic energy and potential energy can be
  transferred back and forth as seen in a swinging
  pendulum or throwing a ball up.

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Transforming Chemical Energy

• Can be seen as chemical reactions occur in living
  things causing bonds to be broken and kinetic
  energy (contraction of a muscle) to be formed.
• Decomposition of dead or decaying matter.

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Transforming Electrical Energy

• Electrical energy can be transformed to sound
  energy (listening to the radio)
• Electrical energy can be transformed to chemical
  energy (neurons fire and release chemicals)

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Transforming Thermal Energy

• Thermal energy can be changed to mechanical
  energy (steam used to move locomotives)
• Thermal energy can be transformed to light
  (radiant) energy (glowing metal on stove)

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Generating Electrical Energy

• Generator- device that transforms kinetic energy
  into electrical energy
• Turbines- set of steam powered fan blades that
  spins a generator at a power plant.

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Electric Power Plants

• Power plants- most power plants use energy from
  coal to start the transformation of energy
  similar to below.

Chemical Energy of Coal
Kinetic Energy of Steam
Thermal Energy of Water
Electrical Energy
Kinetic energy Of turbine
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Sources of Energy

• Energy that we use comes from two main sources
• Renewable resources- resources that can be
  replaced
• Nonrenewable resources- resources that cannot be
  replaced

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Nonrenewable Resources

• Fossil Fuels- formed from the remains of once
  living things.
• - energy from these can be traced back to the
  sun through the food chain

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Fossil Fuels- there are three main types of
fossil fuels

• Coal- formed from the remains of plants that once
  lived on land
• Petroleum-(crude oil) formed from the remains of
  microscopic organisms in the oceans.
• Natural gas- sometimes found along with deposits
  of petroleum also formed from ancient ocean
  microscopic life

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Coal

• Primarily used for generating electricity also
  used for paper production and iron and steel
  production.
• Coal is mined from deposits in two methods

Surface mining
Underground minin
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Petroleum

• Refining petroleum produces gasoline, kerosene,
  asphalt and petrochemical products such as
  plastics some perfumes and insecticides are made
  from products of crude oil

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Natural gas (methane)

• Natural gas is used to heat ( and in some cases
  cool) homes and other buildings also used for
  generating electricity
• Burns the cleanest of the fossil fuels
• Can be produced- (by-product of decaying organic
  matter)

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Whats so bad about these fossil fuels?

1. Energy crisis result of over dependence on
   fossil fuels
2. Burning fossil fuels releases sulfur dioxide
   which mixes with rain and causes acid rain
3. Burning fossil fuels also releases carbon dioxide
   which contributes to the greenhouse effect

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Nuclear energy

• Energy from fission (splitting of the atom) can
  be converted to other sources of energy such as
  electricity
• Negatives- produces radiation that has to be
  contained Uranium is nonrenewable

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Renewable Resources

• Solar energy
• Geothermal energy
• Tidal energy
• Wind energy
• Hydroelectric energy
• Biomass

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Solar energy- energy from the sun

• Collected by thermal collectors (roofs) or
  photovoltaic cells (calculators, roofs,
  satellites)

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Geothermal energy- heat from deep inside the
earth is used as an energy source
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Wind energy- windmills convert kinetic energy to
electrical energy
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Hydroelectric energy

• Water that is behind a dam can be used to move
  turbines and generate electricity.

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Tidal energy

• Energy from the ocean tides can be used to
  generate electricity.

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Biomass

• Energy from living things (primarily plants) can
  be used for fuel.