Conservation of Energy

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Conservation of Energy
09 May 2016
Objectives Be able to describe what the Conservation of Energy is and understand that as energy is transferred it gets spread out. Objectives Be able to describe what the Conservation of Energy is and understand that as energy is transferred it gets spread out.
HSW AF5 Explain ways of modifying work to improve accuracy and precision. HSW AF5 Explain ways of modifying work to improve accuracy and precision.
Used before in Will use again in
PLTS Independent enquirers analyse and evaluate information, judging its relevance and value PLTS Independent enquirers analyse and evaluate information, judging its relevance and value
Used before in Will use again in
Keywords Wasted, dissipated, directly
proportional, accuracy, precision.
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Outcomes

• All students should be able to describe what the
  principle of conservation of energy is.
• Most students should be able to describe an
  example when, as energy is transformed it gets
  spread out and more difficult to use.
• Some students should be able to describe how to
  make the experiment more accurate and precise.

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Braniac pendulum

• http//www.youtube.com/watch?vZbCLAZSPLNkpCAB44
  595BDD39B39playnext1index5

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Conservation of Energy
In any energy change there is ALWAYS some waste
energy e.g. a light bulb
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• Energy is measured in (J) Energy cannot be
  created or destroyed. It can only be from
  one form to another form.
• In other words Energy is always...
• When energy is transferred and/or transformed
  only part of it may be transferred/
  transformed, the rest is .
• Energy will eventually be transferred to the
  which will get ..

Joules surroundings conserved
usefully wasted transformed warmer
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Practical Time!!

• Bungee jumping
• Aim
• To find out how much energy a bungee jumper loses
  in one jump as a percentage of their initial
  energy.

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Bungee!!!!

• http//www.youtube.com/watch?vlAZIxuxjogI

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• Part 1
• In one jump, a bungee jumper starts and finishes
  with gravitational potential energy.
• The change of gravitational potential energy of a
  bungee jumper is proportional to the change of
  height between the lowest and highest position.
• Use a suitable object on an elastic band as the
  bungee jumper.
• Repeat your test several times to check the
  reliability of the measurements. Record all your
  measurements in a table.
• Use your measurements to work out the percentage
  of the initial energy the jumper has after one
  complete jump.

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Bungee Jump PracticalAnalysis and Evaluation
Initial Height Final Height Final Height Final Height Final Height of original height ((final height/initial height)x100)
Initial Height 1 2 3 Average of original height ((final height/initial height)x100)

• Part 3
• Draw an energy transfer diagram for the Bungee
  Jumper.
• Explain the energy changes that take place during
  one complete jump and what type of energy is
  lost.
• Part 4
• Evaluate experiment by explaining how the method
  or equipment used could be changed to make it
  more accurate and precise.

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Plenary - The Big Q how can we improve accuracy
and precision?

• A lightbulb maker claims that its 100 Watt bulb
  gives off 20 Joules of light per second. The
  student uses the set up below to heat up some
  water and measure the change in temperature of
  water over a ten minute period to calculate the
  heat energy it gives off.

thermometer
From her calculations, she finds that the water
receives 50 Joules of Heat energy every
second. All What is the conservation of
energy? Most Why does she measure the heat given
off, when the claim was made about light? Explain
by using the conservation of energy. Some Look
at the students experiment describe how she
could have changed it to make her results more
accurate. What could she have done differently to
make the experiment more precise?