yr9 - static electricity

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  1. 1. Dr Pusey www.puseyscience.com
  2. 2. Recap of the atom An atom consists of a nucleus containing protons (positively charged) and neutrons (no charge). Electrons are present in the region of space outside the nucleus. They are negatively charged and weakly bound to the atom.
  3. 3. From: http://blog.ssis.edu.vn/103059/2013/09/17/does-the-color-of-hair-affect-how-much-static-electricity-it-can-carry/
  4. 4. Static Electricity When an object has an imbalance of protons and electrons More protons gives it a _________ charge More electrons gives it a _________ charge Lightning Charge imbalance between clouds and the earth Eventually, the charge is equalised with a massive spark Scientists still dont fully understand this mechanism Lightning in slow motion
  5. 5. Charge Imbalance NOT CAUSED BY FRICTION correct your friends! Caused by the Triboelectric Effect: Some materials will keep hold of the electrons when pulled apart from another material. This depends on the materials used Negative Plastic Polyester Hard Rubber Cotton Paper Silk Fur Wool Hair Glass Positive Which materials keep hold of charge
  6. 6. Charges Neutral = no overall charge Opposite charges attract, like charges repel
  7. 7. How static builds up Two perfectly neutral objects just sitting around doing nothing interesting When they make continued contact and separation, the cloth keeps all the electrons The rod now has more protons than electrons, and is positively charged Describe what would happen if two positively charged rods were brought together
  8. 8. Like Charges Repel Q: Describe what would happen if the cloth were brought back near the rod
  9. 9. Opposite Charges Attract Q: If the water is neutral - Describe how this is working! http://www.thenakedscientists.com/HTML/experiments/exp/bending-water-static-attraction/
  10. 10. Opposite Charges Attract Answer: The negative charges of the balloon repel the waters electrons away, which make an area of the water positively charged. This is then attracted to the negatively charged balloon! This positive charge on the water is called an induced charge. http://www.thenakedscientists.com/HTML/experiments/exp/bending-water-static-attraction/
  11. 11. Recap What IS static electricity? What CAUSES static electricity? Name 3 examples of static electricity
  12. 12. Recap What IS static electricity? The imbalance of electrons and protons causing a net or resulting charge on an object What CAUSES static electricity? Triboelectric effect, where electrons are passed from one object to another after making contact. Material dependent. Name 3 examples of static electricity Lightning, bending water with a balloon, feather dusting, clingy clothing being in the dryer