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ELECTRICITY----STATIC AND CURRENT

ELECTRICITY----STATIC AND CURRENT. What is happening in these pictures?. STATIC ELECTRICITY. A BUILD UP OF CHARGE( electrons ) from one object to another , without a flow of charge. 3 ways to create static electricity: conduction : build up of charge by direct contact between 2 objects.

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ELECTRICITY----STATIC AND CURRENT

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  1. ELECTRICITY----STATIC AND CURRENT

  2. What is happening in these pictures?

  3. STATIC ELECTRICITY A BUILD UP OF CHARGE( electrons ) from one object to another, without a flow of charge.

  4. 3 ways to create static electricity: • conduction: build up of charge by direct contact between 2 objects Van de graph machine

  5. 2. Induction: build up of charge by force of attraction or repulsion WITHOUT touching one object to the other ( through open space ) Balloon Demo with Salt ( sugar ):

  6. An electroscope demonstrates induction

  7. Static electricity by friction 3. Friction: build up of charge by rubbing one object against another. Rubbing hair with balloon

  8. Static friction- study jams • http://studyjams.scholastic.com/studyjams/jams/science/energy-light-sound/electricity.htmhttp://studyjams.scholastic.com/studyjams/jams/science/energy-light-sound/electricity.htm

  9. Write the letter that most applies for each word. 1.___ Repel A. Objects with opposite charges come together. 2.___ Electroscope B. Detects charges. 3.___ Attract C. Objects with like charges jump apart. Answer the questions. State the Law of Electric Charges: _______________________________________   ____________________________________ List the three ways in which an object can become charged: 5) 6) 7)

  10. When an object becomes charged, one object ________ electrons, and one object _______ electrons. • multiple choice:  • _____ Electric force is found between • a) Charged objects b) credit cards c) criminals • _____ The area around a charged particle that can exert a force is called : • a) electric force b) electric shock c) electric field • 11. ______ The build up of electric charges on an object is • a) current electricity b) static electricity c ) electric discharge

  11. Use the word bank to select your BEST answer. FRICTION (f)INDUCTION (i)CONDUCTION (c) 12._____Electrons transferred from one object to another by direct contact. 13.____ Charges on an object rearrange without direct contact when a charged object is near it. 14. ____Rub 2 objects together. The electrons are transferred. 15. ____Rub a balloon on a wool sweater, and place it near a wall. 16. ____ Walking across a carpet.

  12. E. True /False. CORRECT the False!! 17.____ A lightning bolt is an example of electric discharge. 18.____ An electroscope can tell if the charge is pos. or neg. 19.____ Static electricity is NOT as noticeable in the summer because of the dryness in the air. 20._____ Lightning is a result of the negative charges in the clouds being attracted to the negative charges on the ground.

  13. http://phet.colorado.edu/en/simulation/balloons2011 electricity.ppt

  14. Lightning video • http://player.discoveryeducation.com/index.cfm?guidAssetId=5AE05296-1087-4C59-A5B9-4585869125DC&blnFromSearch=1&productcode=US

  15. Ice hockey simulation • http://phet.colorado.edu/en/simulation/electric-hockeyhttp://phet.colorado.edu/en/simulation/electric-hockey

  16. Current electricity • Current is a flow of electric charges. It is not a build up of charge that is discharged. • All current elec. needs a circuit—a pathway for electric charges to flow.. • All circuits must have at least 3 parts : 1) wires, 2) a source and 3) a load(s).

  17. Parts of a circuit wires Source of electricity Load

  18. Conductors • Conductor: a material that easily allows the flow of electric charges. • It gives very little resistance to the flow of charge. ( metals – copper, aluminum , etc )

  19. Insulators • Insulators:do not easily allow for the flow of electric charges through them. • Ex: glass, plastic, certain rubber materials, cloth.

  20. Current electricity– brain pophttp://www.brainpop.com/technology/energytechnology/currentelectricity/ • http://www.brainpop.com/technology/energytechnology/currentelectricity/

  21. Types of circuits • http://www.brainpop.com/science/energy/electriccircuits/http://www.brainpop.com/science/energy/electriccircuits/

  22. Law of electric Charges • Like Charges repel; Unlike charges attract.

  23. 2 main types of circuits • 1. Series Circuit:only 1 pathfor the electric charges to flow • 2. Parallel Circuit: has More than one path for the electric charges to flow.

  24. Series circuit

  25. Now, let’s draw it in your notes:

  26. Resistance • This is what “slows down” the movement of the electric charges … so they hit each other more… • What do you think could ADD resistance in a circuit ? • Add more loads to the same circuit • Heat • Longer wires • Thinner wires

  27. Circuit Mini Lab • Take a sheet of computer paper. • You have 4 drawings, 4 circuits to build, and 4 questions to answer… Let’s do the drawings together, then you can build, and answer the questions: • You Label: wires, source, load, direction, terminals, switch • 1. 3. • 2. 4.

  28. 2. Parallel Circuit: has more than 1 path for electric charges to flow, so if 1 load goes “out,” the other loads will still work !

  29. Draw a parallel circuit

  30. Circuit simulation http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc

  31. Alternating Current - AC • Electric charges move back and forth—homes and buildings. Ex: 60 V one way and 60 V the other way,= 120 Volts

  32. Let’s recap: • 2 types circuits 2 types current direction 1 way Direct current Series Parallel Alternating current Back and forth Direct with a battery One way

  33. BATTERIES • Electrolytes- liquids/acids that cause a chem. reaction, that releases electric charges • Batteries (usually) are DC-direct current- where the electrons flow only in 1 direction. CONVERT CHEM. ENERGY TO ELECTRICITY. 2 TYPES: DRY CELLS WET CELLS Dry cells have paste-like electrolytes, and these are the batteries you are used to using. Wet cells have liquid electrolytes. ( car batteries)

  34. Wet cell dry cell

  35. Inside a dry cell

  36. Inside a wet cell

  37. Watch the stick figures move the charges Back and forth, creating a potential difference In voltage, making current ! http://phet.colorado.edu/en/simulation/battery-voltagehttp://phet.colorado.edu/en/simulation/battery-voltage

  38. Circuit breakers and fuses Circuit breaker-open a circuit to keep from Overload. Plug fuses • Circuit breaker fuses

  39. Ohm’s law I = V/ R Current = voltage/ resistance. Discuss wires and resistance!!

  40. What current would flow through a resistor of 20 ohms connected to a 12 V supply?• [A] 240 A • [B] 1.66 A • [C] 0.67 A • [D] 0.067AWhat current would flow through a resistor of 40 ohms connected to a 10 V supply?• [A] 400 A • [B] 4 A • [C] 0.25 A • [D] 0.025AA 100 ohm resistor is connected to a 20 V supply. What current flows?• [A] 0.02 A • [B] 0.05 A • [C] 0.2 A • [D] 0.5 A • [E] 2000 AWhat value of resistor would be used to permit a current of 0.2 A to flow using a 6V supply?• [A] 0.03 ohms • [B] 0.3 ohms • [C] 3.0 ohms • [D] 30 ohms • [E] 300 ohms

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