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Daily Work Organizer

Daily Work Organizer. Do Now:. Homework: (2) Reading Log 24: pg 235-236 Due Friday: Signed Progress Report. New HW System. HW is stamped You write the number on the top of the assignment (#1) Reading Log 23

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Daily Work Organizer

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  1. Daily Work Organizer Do Now: Homework: (2)Reading Log 24: pg 235-236 Due Friday: Signed Progress Report

  2. New HW System • HW is stamped • You write the number on the top of the assignment (#1) Reading Log 23 • Stapleall your HW in order to the back of your Cornell notes at the end of the chapter

  3. Jobs • 1 PowerPoint Master • 2 Graded Work Gurus • 1 Whiteboard Cleaner!

  4. Tuesday Tutoring • Everyone is Welcome! • Mandatoryif your grade is below a C • If you can’t make, you must provide Ms. Gamm with a written or oral explanation.

  5. Static Electricity It’s what we see…

  6. The Point of Cornell Notes • If you don’t review, you would need to spend 40-50 minutes re-learning each hour of material later Without Review, only about 20% of information is remembered after initial memorization Write Questions! • Within 24 hours - spend 10 minutes reviewing • A week later spend 5 minutes to "reactivate" the same material Write the Summary

  7. Charges • Rubbing plastic or glass makes them attract to bits of paper or dust • Same objects charged the same way will repel each other • Some charged objects attract each other

  8. Charges • All charged objects either attract or repel each other • This implies 2 types of charges • Benjamin Franklindecided to call the charge on rubbed glass positive

  9. Electricity • One of the first objects to hold this charge was amber • The Greek word for amber is elektron • Electricity • Electron

  10. Charge • To understand Charge, let’s look at the atom • Protons (nucleus) are positively charged • (repels charged glass) • The electrons are negatively charged • (attracts charged glass)

  11. Charge • Even though protons are much bigger (2,000x’s bigger than electron), the – and + charges are the same size. • If an atom has equal number of electrons and protons the charge is zero. ____? • 3 electrons (blue) and 3 protons (red) • Net charge is zero (neutral charge)

  12. Charge Rules • In order to be charged, an object must have extra protons or electrons • The following facts help understand charges: • In solids, positive charges do not move protons are fixed in place

  13. Charge Rules • In solids, negative charges can move • conductors: electrons move all about material

  14. Charge Rules • In solids, negative charges can move • conductors: electrons easily move about material • insulators: electrons mostly move around atom

  15. Charge Rules In fluids, both protons and electrons can move all around

  16. Charge Rules • Objects want to be neutral. • If given a path to the earth, electrons will flow out until the object is neutral. • This is called grounding. v

  17. Charge by Rubbing • Every atom attracts electrons (e-) a certain amount • When you rub two objects together the object that attracts electrons more will steal e- + −

  18. Charge by Rubbing • This stealer becomes negative (more e-) and the other object becomes positive (lost e-) What will happen to the charge when the bars separate? 4 Electrons 6 Electrons 4 Electrons 2 Electrons

  19. Transferring Charge • This stealer becomes negative (more e-) and the other object becomes positive (lost e-) • Only works if there is contact

  20. Daily Work Organizer Do Now: • Homework: • (3)Reading Log 25: pg248-252 • (4) Finish Activity pg 238-239 • (5) Problems 1-3 Pg 246 •  Signed Progress Report

  21. 1. Where is the Electrostatic Force greatest? 2. Where is the Electrostatic Force smallest? Q = charge

  22. Retake: Monday 3:15 – 4:15 Test Corrections due Monday

  23. Warning • If you do not return your test to me you get -10 points • All tests mustbe returned by Tuesday

  24. Conduction A charged conductor touches a neutral conductor Total Charge = protons - electrons

  25. Conduction A charged conductor touches a neutral conductor

  26. Conduction A charged conductor touches a neutral conductor The electrons spread out so that the charges on both are equal What will happen to the charge when the conductors separate?

  27. Conduction A charged conductor touches a neutral conductor The electrons spread out so that the charges on both are equal

  28. Visualizing Electric Charge pg 237 Neutral Draw 3 units of charge (protons & electrons) • In each bar

  29. Induction pg237 6 units of charge (protons or electrons) Neutral 9 protons & 9 electronstotal

  30. Conduction pg 238 Initially Neutral 6 units of charge (protons or electrons) What can happen when 2 charged objects touch? Total protons: 6+9 = 15 Total electrons= 9 Difference: 6 protons Charge has to be evenly distributed… How many electrons should each object have? 9 protons total

  31. Charging by induction pg239 6 units of charge (protons or electrons) Neutral Charged objects want to be neutral… How many electrons should enter from the ground? 9 protons & 9 electronstotal

  32. Vocab Charging by Induction • A method used to charge an object without actually touching the object to any other charged object

  33. Vocab Charging by conduction • Electrons are • transferred from one material to another through contact

  34. Induced Polarity • How do charged objects attract neutral objects? • By inducing a charge on the neutral object. • A neutral balloon has no effect on wall’s e- • The neutral wall has e- found randomly around nuclei of the atom

  35. Induced Polarity • Let’s charge the balloon • Now the e- in the wall are being repelled • This leaves the exposed wall acting positive • Negative and positive charges attract each other

  36. What was wrong with this movie?

  37. Electrostatic Force • Electric Force is 1039 times larger than gravity • Coulomb studied charge with charged metal balls • Let’s look at how the amount of charge on each ball and the distance effect the electrostatic force

  38. Coulomb’s Law • Electrical force is proportional ( ) to both

  39. Coulomb’s Law • These lead to one equation called Coulomb’s Law: Electric Force in Newtons (N) charge in Coulombs (C) distance between centers in meters (m)

  40. Coulomb’s Law • A Newton is about equal to ¼ pound • A Coulomb is the amount of charge in 6.25 x 1018 electrons or protons

  41. ExampleTwo charged spheres, one with 1x1012 extra electrons and one with 2x1012 extra protons are separated by 50 cm. What force do they exert on each other? Given: Want:

  42. Examplesolve for FE - force is attractive

  43. Time to practice Go to pg. 235

  44. Daily Work Organizer Do Now: • Homework: • (7)Reading Log 26: 255-256 • (8) Problems Set 8 • (9)Finish E-field activity 253 •  Test Corrections!

  45. Daily Work Organizer Do Now: • Homework: • (7)Reading Log 26: 255-256 • (8) Problems Set 8 •  Test Corrections!

  46. Answers • A • C • A • C • E • A • B • A • D • B • A • A • B

  47. If distance is doubled: #3 dfinal= 2dInital FE initial = 12 N

  48. Tutoring After School Today, room 308

  49. Static Electricity Test on Tuesday Why? Because I don’t want you that have to study over Thanksgiving Advice: Finish your Cornell notes over the weekend

  50. Labbettepg 240 Read pg 240 Complete Part 1 with your lab group

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