charged and how does a charged object affect other objects in its vicinity What makes up all matter What does it mean to be charged What is GROUNDING What are insulators amp conductors ID: 1031418
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1. ElectrostaticsHow can an object get charged and how does a charged object affect other objects in its vicinity?
2. What makes up all matter?What does it mean to be “charged”?What is GROUNDING?What are insulators & conductors?What are the (names &) methods of charging?Hey wait, what IS charge? A measurement, a concept….?What do charged objects do? (to other objects)Essential Questions for Electrostatics
3. Matter is made of Neutrons, Protons and ElectronsProtons have POSITIVE chargeElectrons have NEGATIVE chargeNeutrons are unchargedWhich has “more” charge?Being charged means having an excess or shortage of __________Which charges move to charge an object?Why do they move?Electric Charge
4. This term is used for the process that “un-charges” a charged object.It is performed by contacting a charged object to an object that can give, OR receive ___________ charges, so that the initially charged object is made neutral.It can (partially) happen w/o contact when one object that is highly charged discharges across a gap – that is a sparkGrounding (UN-CHARGING)
5. A good CONDUCTOR allows negative charges to travel around through the material making up the conductor, with very little RESISTANCE.A good INSULATOR makes it very hard for negative charges to travel around through the material making up the insulator. These have a lot of RESISTANCE.A SUPERCONDUCTOR is a material that allows negative charges to flow through it without any RESISTANCE.Conductors and Insulators
6. Conductors and Insulators
7. Conductors and Insulators
8. What happens when fur is rubbed on the rubber wand? Cloth on the glass wand?What happens when the wand is brought near a metal bar or gray sphere? Why?What happens when the wand touches the metal bar or gray sphere, and then is held near? Why?What happens when the two gray spheres that have been touched by the same wand are brought near each other? Why?What happens when the two gray spheres that have been touched by different wands are brought near each other? Why?What happens if someone touches the metal bar or spheres after they have been touched by a wand?Questions From Demos
9. Charging by :FrictionMaterials rubbed “against” each other transfer …ConductionA charged object is brought in contact with a conductor and there is a transfer of …InductionA charged object is brought NEAR a conductor, the conductor is grounded, there is a transfer of….. the ground is removed, and finally the charged object is moved away from the conductorPolarization (not really charging, as a polarized object’s NET charge can be zero)A charged object is brought near a neutral conductor, electrons on the conductor move (toward, or away from the charged object) and then the polarized object behaves as if it has the ________ charge as the object that caused the polarization. Charging an Object
10. 1. Use the negatively charged wand to charge the electroscope by CONDUCTION (needs contact). Remove the wand, then bring it back near scope. You observe:Charge the glass with the cloth. Bring it near the charged scope. You observe:2. Ground scope. Use the negatively charged wand to charge the electroscope by INDUCTION (no contact with charged wand, but a ground must be connected and disconnected at the appropriate time. Remove the wand, then bring it back near scope. You observe:Charge the glass with the cloth. Bring it near the charged scope. You observe:3. Record the four steps to charging the scope by induction. Do you know what goes in in each of the four steps? These are found in Lesson 2b on PCRCharging Investigation
11. The SI unit for charge is the COULOMB (C)The charge of one electron is -1.6x10-19CThe charge of one proton is +1.6x10-19CThe quantity of charge equal to 1.6x10-19C is often written as e so the charge of one electron is –eTo calculate the charge of a certain number of electrons or protons, use the equation:Q = +ne where Q is quantity of charge, and n is the # of charge carriersQuantity of Charge
12. https://www.youtube.com/watch?v=nwnjYERS66U
13. To calculate the charge of a certain number of electrons or protons, use the equation:Q = +ne*where Q is quantity of charge, and n is the # of charge carriers*e = 1.602 x 10-19C* The mass of an electron was also determined to be 9.11x10-31kgQuantity of Charge
14. If sphere on a VanDeGraaf generator is charged to10,000 volts, it has had 1.74x1012 electrons moved off of it. What is the charge of the sphere (sign and number)?Example: Quantity of charge
15. Opposite charges attract and like charges repelCharged objects can attract neutral objects, by polarizing the neutral objects. Conductors are easy to polarize, insulators are not easy to polarize.Electrons are the only charges to get transferredThe force between charged objects can be mathematically described by Coulomb’s LawBehavior of Charge and “Charged” Objects
16. Questions from the assignment last night?
17. Review Electroscope InvestigationPCR Static Electricity Lessons 1&2CYULesson 1: a(1), b(1-6), c(all), d(1-3), e(1,2,4,5,6)Lesson 2: a(3,4), b(4), c(all), d(all)Quest: ElectrostaticsAssignment
18. 1. If one million electrons are added to the top of a Van de Graff generator, what is its charge in coulombs?2. Use the negatively charged wand to charge the electroscope by INDUCTION. Remove the wand, then bring it back near scope. You observe:Charge the glass with the cloth. Bring it near the charged scope. You observe:3. Check the four steps to charging the scope by induction. Do you know what goes in in each of the four steps?Electrostatics Day 3 Warm-up
19. But wait, what IS force?When does an electric force occur?What factors affect the size and direction of the electric Force on an object?Electric Force: What factors affect the size and direction of the electric Force on an object?
20. What affects the size and direction of the electric force one charged “particle” exerts on another charged “particle”?
21. What is the mathematical relationship between electric force (in newtons) and the:quantity of charge A (in coulombs)?quantity of charge B (in coulombs)?distance (in meters) between charges A & B?What affects the size and direction of the electric force one charged “particle” exerts on another charged “particle”?
22. |Fe|(N) and QA(C)? (What if you double, triple, … QA)|Fe|(N) and QB (C)? (What if you double, triple, … QB)|Fe|(N) and d (m)?Fe is electric forced is distance between the electric chargesUse the Gizmo simulation: Coulomb Force Google Username: Password: What is the mathematical relationship between:
23. Fe = k(Q1 Q2)/d2Fe:k = 9 x 109 (Nm2/C2)d: Q1 & Q2 are:Coulomb’s Law
24. Ex: What is the force of attraction/repulsion between an electron and a proton in a hydrogen atom? They are 53pm (5.3x10-11m) apart.
25. The concept of a field is utilized by scientists to explain the surprising force phenomenon that occurs in the absence of physical contact.Electric Fields
26. The electric field is a ratio, comparing the size of the force on a charged object to the size of the charge E=Fe/Q Fe=EQA slightly charged object in an electric field will experience a small electric force, while a heavily charged object will experience a ____________ force.Electric Field Defined (mathematically)
27. As the distance from a charged object doubles, the electric field ________________Ex: If a small “test charge” is 0.40m from the center of a charged Van de Graff, it experiences an electric force F. How big is the force when the test charge is:0.80 from the center?1.20m from the center?0.20m from the center?Electric Field vs Distance from Charged Object
28. The Butter Gun
29. The field “lines” are really arrows that show the direction of force on a positive “test” charge, and show field strength by how closely the lines are spacedElectric Field Lines (or lines of Force)
30. Electric Field Lines (or lines of Force)Electric Field Lines for Two (different, isolated) Point Charges
31. Examples of field lines
32. Skim PCR Static electricity 4C, and complete the CYU questionsComplete WS on Electric FieldsPlay Electric Field HockeyGoogle Phet, go to play with sims, Physics, electricityAssignment:
33. If the electrons from one gram of hydrogen were placed in a container and taken to the South Pole, and the protons from the same gram of hydrogen were placed in a container and taken to the North Pole, How much force would these two containers exert on each other?Coulomb’s Law Problem