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A set of slides created to teach Energy to learners at Bishops Diocesan College in Cape Town.

A set of slides created to teach Energy to learners at Bishops Diocesan College in Cape Town.

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Energy Presentation Transcript

  • 1. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net ENERGY K Warne
  • 2. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Energy • Write down a definition that explains what energy is. The ability to do work. • Write down as many forms of energy as you can. Energy can be… Chemical, movement (kinetic), electrical, solar, nuclear, potential (stored), radiant, light, sound, hydro-electric
  • 3. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Forms of Energy Form of Energy Source/Origin Transferred into/Used Process/ Transducer Solar Sun Heat/Electricity Chemical Solar panels photosynthesis Wind Wind - Sun Electricity/ Identify as many different forms of energy as you can, try and decide where the energy comes from (source), where it goes to (Transferred into...) and where this takes place (process/transducer).
  • 4. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net NUCLEAR ENERGY Is the process in which the nucleus of heavy (radioactive) elements are split apart. This releases a lot of energy. The process in which small nuclei are joined together (fused) to form larger nuclei. This releases VAST QUANTITIES of energy. Both these forms of energy can be used to provide the energy we need. Find out why they are both called “Nuclear”, how are they different? Give an examples of both. H H He FUSIONFISSION
  • 5. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Origins of Energy - The Sun • Energy can never be created or destroyed. • It can only be transformed from one form to another. • Energy from the sun (solar - heat/light energy) • Enables plants to grow (photosynthesis) • Which can be harvested /eaten (food/fuel - chemical energy) • used to do work (heat/light energy)
  • 6. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Potential Energy Gravitational m Any object that is above the ground has the POTENTIAL to fall Down. It has potential energy (EP) - given by: Ep = mgh where; m = the mass of the object (kg) g = the acceleration due to gravity (10m/s2) h = height above the ground (m) If the object is lifted up then it gains the same amount of potential energy again. g (10m/s2) EK Potential Energy (mgh) m m Ep Potential Energy GAINED Object could fall down h
  • 7. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Mechanical Energy - Falling Object m Any object that is above the ground has the POTENTIAL to fall Down. The potential energy EP =mgh (Height) lost would be converted into speed (kinetic energy) EK. Ep(Top) = Ek(Bottom) If the object is lifted up then it gains potential energy. At any time the sum of these two is called the MECHANICAL ENERGY - and it stays constant. Ep Potential Energy LOST EK kinetic energy gained = Ep lost! E = Ep + Ek m 4kg 8m Ep = mgh Ek = 320J E = Ep + Ek = 320 + 0 = 320J E = Ep + Ek = 0 + 320 = 320J 4m E = Ep + Ek = 160 + 160 = 320J Ep = 0
  • 8. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Mechanical Energy - Falling Object m Any object that is above the ground has the POTENTIAL to fall Down. The potential energy EP =mgh (Height) lost would be converted into speed (kinetic energy) EK. Ep(Top) = Ek(Bottom) If the object is lifted up then it gains potential energy. At any time the sum of these two is called the MECHANICAL ENERGY - and it stays constant. Ep Potential Energy LOST EK kinetic energy gained = Ep lost! E = Ep + Ek m 4kg 8m Ep = 320J Ek = ?? 320J E = Ep + Ek = 320 + 0 = 320J E = Ep + Ek = 0 + 320 = 320J 4m E = Ep + Ek = 160 + 160 = 320J
  • 9. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net A pendulum • A person of 60kg is lifted to a height of 30m on a slingshot pendulum and then released. m h ETop = Ep + EK = mgh + 1/2mv2 = (60)(10)(30) + 0 = 18000J Total Mechanical Energy (Top) EBottom = Ep + Ek = mgh + 1/2mv2 18 000 = 0 + 1/2 (60)v2 v2 = 18000/30 = 600 v = 600 = 24.5 m.s-1
  • 10. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Kinetic & Potential Energy Tasks 1. Calculate the potential energy gained by your body as you climb the stairs to the first floor of the school building. 2. Calculate the potential energy gained by a cricket ball 300g that is thrown 4m up into the air. 3. Calculate the potential energy gained by your bag (weigh it) as it is lifted onto your shoulder (estimate or measure height). 4. Calculate the kinetic energy of your body as you are; 4.1 walking (1.5m.s-1) 4.2 running (8m.s-1) 4.3 driving in a car (60km.h-1). 5. Calculate the mechanical energy of a 2 ton airplane flying at a height of 30 000m at a speed of 500 km.hr-1.
  • 11. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Energy Transformations
  • 12. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Energy Transformations A car accelerates from rest to 120km/hr and then comes to a halt again. List the energy transformations that take place.  Chemical Potential energy - in the petrol.  Heat energy in the engine as the petrol burns.  Kinetic energy as the engine and car begin to move.  All this energy is converted into heat as the car brakes and comes to a halt.
  • 13. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Energy Efficiency - Light Bulb • Input: Electrical • Outputs: Heat & Light • Page 108 - analysis of energy input and outputs for a light bulb • Transfer these to a pie chart. (Outputs only) • Energy Spreadsheet Electrical
  • 14. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Temperature • Temperature is a measure of the average kinetic energy of the particles in a substance. • The HOTTER the substance the GREATER the KINETIC ENERGY and the FASTER the particles vibrate.
  • 15. Heat • HEAT is the ENERGY which passes from a HOT object to a COLD object. • HEAT is ENERGY on the MOVE! Heat is transferred by: • Conduction • Convection • Radiation
  • 16. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Heat - energy on the move 1. Radiation - Infra red radiation - rays of heat energy that move in straight lines through space. 2. Convection - movement of heat energy in a current of liquid or gas. Hot air rises (less dense) causes convection currents. 3. Conduction - Heat transmitted through a substance or from one substance/object to another by direct contact. H/W: Draw a diagram/picture showing how each of these operates in a example.
  • 17. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Heat - preventing heat loss. Write down ways that energy losses in a house can be prevented. Ceiling insulation - Aerolite Cavity wall (insulation) Carpets - underfloor heating Windows - curtains - draft excluders - double glazing Doors - draft excluders
  • 18. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Energy • Chemical energy in the petrol. • Converted to kinetic energy in the engine which moves the car. • Converted to HEAT in the brakes. Discuss the energy transformations that occur when a car drives a certian distance and then stops.
  • 19. SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> www.warnescience.net Hi - This is a SAMPLE presentation only. My FULL presentations, which contain loads more slides (with all the gaps filled in) as well as other resources, are freely available on my resource sharing website: www.warnescience.net (paste into your browser if link above does not work) Have a look and enjoy! Keith Warne