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					Y8 ENERGY
 BIRLEY COMMUNITY COLLEGE
               Types of Energy
                             Chemical
        Light



                                    Kinetic
Heat

                    ENERGY
                                    Potential
Sound



  Electrical                     Nuclear
                       Y7 Revision
• There are 8 types of energy:
• Kinetic, Potential, Electrical, Light, Heat, Sound, Chemical,
  Nuclear
• Energy cannot be made or destroyed but it can change from
  one type to another.

Draw the energy chain for:
• A jack in the box (2 steps)
• A battery powered toy car (3 steps)
• A petrol powered car (3 steps)
• A clockwork radio (5 steps)

Energy is measured in joules (J) or kilojoules (kJ)
1 kJ = 1000 J
         Generating Electricity
     Steam



                             Generator




                Turbine
Boiler




                 Water
Fuel
                               Cooling Towers
      Non-Renewable Energy Resources
 • Most of our energy resources are from fossil fuels:
 • Coal, oil and gas
 • Fossil fuels take millions of years to make

                  How is coal formed?
                    Over
    Prehistoric                     The rocks        The
                    millions of
    trees die                       put lots of      remains of
                    years
    and fall                        pressure         the trees
                    rocks form
    into                            on the           turn into
                    above the
    swamps.                         trees            coal
                    swamps
• Once all the coal is used it cannot be replaced (it is non-
  renewable)
• Oil and gas are also non-renewable
     Non-Renewable Energy Resources
• Oil is formed from the remains of sea-creatures.
• All the energy in fossil fuels came from the Sun.




       Sun                   Trees                    Coal




    Sea Plants


                               Sea
      Non-Renewable Energy Resources
 • Uranium is a metal used in nuclear power stations. It is non-
   renewable because supplies are running out.


      Energy Resource   How long can supplies   • Homework
                                last
                                                  Describe a
           Coal              300 years
                                                  RENEWABLE
            Oil               30 years
                                                  energy
                                                  resource with
           Gas                50 years            writing and
                                                  diagrams (1
         Uranium              60 years            page
                                                  minimum)

• What factors could change these figures?
           Renewable Energy Resources
 • Copy and complete this table of renewable energy resources
  Energy Resource                How does it work?

  Wind

  Solar

  Hydro-electric

  Waves

  Tidal

  Geothermal

  Biogas


• You can find info on these in Energy Booklet p 49 and The
  Earth’s Energy p 14, 21 & 22. Or you could use the internet.
                       Joule Island
• You are in charge of 20 scientists
• You are all going to live on Joule Island for 3 years
• You must provide all your energy with renewable energy
  resources
• Choose the best places to position your power stations
• You will do a presentation to the rest of the class using this
  computer and projector.
= High Ground
= Forest
= River
= Hot Spring
= Wind direction
         Heat Energy and Temperature
A spark at a temperature of 1000 OC has less heat energy than a
                  bath of water at 20 OC ! WHY?




                     Hot – But low
                        energy
                                      Cold – But
                                     high energy


•   Heat energy makes particles move faster.
•   Faster moving particles make a higher temperature.
•   The bath of water has many more particles than the spark.
•   Therefore the bath has more energy in total.
             Transfer of Heat Energy
• Heat energy moves from a high temperature to a low
  temperature.
• Eg Heat moves from a hot cup of tea into the air of colder
  room.
• Why does the temperature of the tea drop more than the
  temperature of the air rises?

How do objects cool down?
• The temperature of 50 ml of hot water was taken every 30 s
  for 10 minutes as it cooled in a room. This was then repeated
  for 25 ml of hot water
• Draw a results table, then do your experiments.
• Plot all your results on one line graph.
                   Graph to show how water cools

                           •   Mark with an X where the water is cooling down the fastest
                           •   Why does it cool down fastest here?
                           •   What would be the temperature of the water if it was left
                               for an hour?
Temperature (OC)




                           •   Which amount cooled down the fastest?
                           •   Why?



                                                                           50 ml
                   25 ml




                                          Time (s)
           Transferring Heat: Conduction
    HEAT




In conduction, heat is passed between particles.
All metals are good conductors of heat.
Materials which do not conduct heat are called insulators.
Conduction only works in solid materials. Why?
1. What would be good material for the base of a
   pan?
2. What would be good material for the handle of a
   pan?
       Transferring Heat: Convection
                             • Draw the beaker of water
                             • Draw in the convection
                               current
                             • Convection is caused by
                               particles with heat rising and
                               then been replaced with
                               cooler particles sinking.

• Draw this room.            X
• Draw in the convection
  current in the room
• What would happen if the
  heater was placed at X?
• P 12 qu 1-4
                   Homework

• Explain, using diagrams and writing, how a wet suit
  keeps a diver warm by preventing convection.
          Transferring Heat: Radiation
• Radiation is an infra-red light wave.
• It travels at the speed of light (300 000 000 m/s).
• It does not need particles so it can travel through a vacuum.


 Emitting Radiation

 • Dark, dull objects give out a lot of radiation
 • Shiny, light coloured objects do not give out a lot of radiation

 Explain the following:
 • Heaters work better if painted black
 • Tea stays hot for longer in a white cup
 • The back of fridges are painted black
Absorbing Radiation

•Dark, dull objects absorb a lot of radiation
•Shiny, light coloured objects do not absorb a lot of radiation

Explain the following:
•You feel warmer in a black tee shirt in Summer.
•Jacket potatoes don’t burn when cooked in foil
•Very few black cars are sold in hot countries.

The Vacuum Flask
•Vacuum Flasks can keep tea warm for a long time because
they stop the transfer of heat by conduction, convection and
radiation.
•Explain this by doing qu 1,2 on page 22
                       Insulation
• Jaimie builds two identical snowmen. He puts his Granny’s fur
  coat on one and leaves the other naked. Next day the sun
  came out but which snowman melted first?
• Use transfer of heat to explain your answer

 • The naked snowman melts first
 • Heat transfers to the snow from
   the surroundings
 • The fur coat insulates one
   snowman
 • So heat cannot transfer into the
   snow
 • It takes longer to warm up and
   melt
           Is Aluminium Foil an Effective
                     Insulator?
Planning
• What type of heat transfer is affected by Al foil
• How do you isolate this from other heat transfers?
• Draw your apparatus
• How is it a fair test?

Results
• One results table for all your findings
• Draw a graph of your results
• Did you expect this to happen? Why?
                                                                  SE
                                                             TEN N
Evaluation                                                ST        O
• If done again how could it be more accurate?         PA      E RS
                                                          RD P
• How can you extend the tests further?                  3

				
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