Electrical Energy


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Year 9 Electrical Energy - For additional resources visit: http://www.iheartscience.net

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Electrical Energy

  1. 1. www.drecart.com Electrical Energy Sarah Jones
  2. 2. • All matter is made up of atoms. • Centre of each atom is a heavy nucleus. • Surrounding the nucleus is a lot of empty space and tiny particles called electrons (which are constantly moving). • Each electron carries a negative electric charge. Oxygen Atom
  3. 3. • Inside the nucleus are two different particles – protons and neutrons. • Protons are much heavier than electrons and they carry a positive electric charge. • Neutrons have a similar mass to protons but carry no electric charge. sciencewithme.com
  4. 4. The positive electric charge of a proton exactly balances the negative charge of an electron. Atoms contain an equal number of electrons and protons.
  5. 5. • Any particle or substance that has more protons than electrons is said to be positively charged. • More electrons than protons is said to be negatively charged. • Equal amounts of positive and negative charge is said to be neutral. Helium Atom
  6. 6. Static Electricity • Is the build up of electric charge on a surface. • Commonly occurs because of two surfaces rubbing against each other. homeschooljabber.blogspot.com
  7. 7. The electrons are rubbed off one surface – charging is positive – and are transferred to the other surface – charging it negative. www.aapt.org
  8. 8. Current Electricity • Power from batteries and power points is made up of electrons moving along a wire – electric current. • The energy from the moving electrons is transformed into other forms of energy such as heat and movement. www.nmsea.org
  9. 9. Measuring Electricity • Electric Current – when charge flows (measured using a ammeter). • Unit used to measure current is ampere/amps (A). • Voltage – measure of the amount of energy supplied and used by the charges. • Unit used to measure voltage is volts (V). wps.pearsoned.ca
  10. 10. • Supply Voltage – Australia 240V • Some household items use transformers. • A step-down transformer reduces 240V to the amount required by an appliance.
  11. 11. Batteries • Portable electrical energy. • Wet Cell – two electrodes placed in a liquid electrolyte i.e. conducts electricity. • Dry Cell – used in torches, toys etc. don’t leak because they use paste instead of liquid. • Photovoltaic Cells – solar cell.
  12. 12. • Resistance – when electrons pass along wires their path is restricted by the atoms that make up the wires. • A measure of how difficult it is for an electric current to flow. https://learn.sparkfun.com/tutorials/resistors
  13. 13. Conductors and Insulators • Conductors - materials with little resistance to the flow of electric charge (e.g. copper wires used in most electric circuits). • Little energy is needed for electric charge to flow through conductors. • Most metals are very good conductors of electricity.
  14. 14. • Insulators - materials with a lot of resistance to the flow of electric charge • Allow very little or no electric current through e.g. air, rubber and plastic.
  15. 15. Circuit Diagrams Circuit diagrams are universal so they can be used all over the world.
  16. 16. Series Circuit • A string of Christmas tree lights are all connected to the same power supply. • If you remove a single light the rest of the lights will go off. • This is because the lights are connected in series.
  17. 17. Parallel Circuit The ceiling lights in most homes need to be connected together so that if one light globe or tube stops working, the others remain on – this requires a parallel circuit.