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Physics

Physics. Static Electricity. Making static electricity. Try out the following: Cut up some small pieces of paper. Rub a biro in your school jumper and then hold the biro next to the pieces of paper – What happens?. Making static electricity. Try out the following:

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Physics

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  1. Physics Static Electricity

  2. Making static electricity Try out the following: Cut up some small pieces of paper. Rub a biro in your school jumper and then hold the biro next to the pieces of paper – What happens?

  3. Making static electricity Try out the following: 2. Rub a biro in your school jumper and then hold the biro next to a gentle stream of water running from the tap – What happens?

  4. Making static electricity Try out the following: 3. Blow up a balloon and rub it along your school jumper. Then hold the balloon next to your hair or the stream from the tap! What happens?

  5. What is static electricity? • What do these things have in common? • Crackles when combing hair. • Cling film sticking to your hands. • Clothes clinging to each other in a dryer. • Getting a shock when rubbing your feet on a carpet. • Lightning. They are all caused by static electricity. Static electricity is due to electric charge that builds up on the surface of an object.

  6. Where does static charge come from? All materials are made of atoms, The electrons have a negative charge. The protons have a positive charge. electron (negative charge) proton (positive charge) An atom has equal amounts of negative and positive charges which cancel each other out (- no overall charge)

  7. Where does static charge come from? When two materials are rubbed togetherelectrons can be passed from one material to the other: • One material ends up with more electrons, so it now has an overall negative charge. • One material ends up with less electrons, so it now has an overall positive charge.

  8. Charging a polythene rod

  9. Charging polythene If an insulator made of polythene is rubbed with a cloth, electrons move from the cloth to the insulator. What charge does the cloth now have? The cloth becomes positively charged. What charge does the polythene insulator now have? The insulator becomes negatively charged.

  10. Charging an acetate rod

  11. Charging acetate If an insulator made of acetate is rubbed with a cloth, electrons move from the insulator to the cloth. What charge does the cloth now have? The cloth becomes negatively charged. What charge does the polythene insulator now have? The insulator becomes positively charged.

  12. Investigating how charged objects react to each other

  13. How do pairs of charges behave?

  14. Pairs of charges – attract or repel?

  15. Insulators An object which holds onto a charge is called an electrical insulator – examples are plastic and wood.

  16. Conductors Electrical conductors allow electrical charge to pass through them. Examples: Metals, Ionic substances

  17. Does water hold onto an electrical charge? Water is a (poor) conductor of electricity– it allows some electrical charge to pass through it.

  18. Earthing If a charged object is connected to the earth by a conductor then the electrical charge will flow into the earth.

  19. Earthing We say that the earth is a source and sink for electrons.

  20. Examples of earthing lightening strike…

  21. Why do you only get a shock off a trolley in dry weather?

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