ElectrostaticsElectrostatics

PhysicsPhysics

A. DefinitionA. Definition

The study of electrical The study of electrical charge that can be charge that can be collected and held in collected and held in one placeone place

B. Examples of Static B. Examples of Static ChargeCharge

Socks in a dryerSocks in a dryerSliding feet on carpetSliding feet on carpetRubbing a Rubbing a

balloonballoon

C. Electric states of C. Electric states of MatterMatter

Neutral: negative charge = Neutral: negative charge = positive chargepositive charge

Negatively charged: excess Negatively charged: excess of electrons (eof electrons (e--) )

Positively charged: Positively charged: deficiency of edeficiency of e--

Special NoteSpecial Note

ee-- is responsible for is responsible for understanding understanding electrical phenomenaelectrical phenomena

D. Rules of ChargeD. Rules of Charge

Like charges repelLike charges repelOpposite charges Opposite charges attractattract

ChargeCharge is conserved is conserved

Classes of Matter Classes of Matter A. ConductorsA. Conductors

Crystal Crystal

Lattice: Lattice:

ee-- flow flow

freelyfreely

ConductorConductor2. Description2. Description

material that readily material that readily transfers chargetransfers charge

ee-- are free to move are free to move around in the crystal around in the crystal lattice (sea of elattice (sea of e--))

ConductorConductor3. Examples: 3. Examples: MetalsMetalsWaterWaterEarth (best)Earth (best)

Electric pickleElectric pickle Struck by lightning Roy SullivanStruck by lightning Roy Sullivan

B. InsulatorsB. Insulators

1. Description: e1. Description: e- - are tightly are tightly bound to nuclei and will not bound to nuclei and will not readily transferreadily transfer

2. Examples: plastic, wood, 2. Examples: plastic, wood, glass, rubber, paperglass, rubber, paper

Semi-ConductorsSemi-Conductors1. e1. e- - can move more freely can move more freely than in an insulator, but not than in an insulator, but not as easily as conductorsas easily as conductors

2. Examples: Silicon, 2. Examples: Silicon, GermaniumGermanium

III. A. InductionIII. A. Induction

1. How is it done?: Bring a 1. How is it done?: Bring a charged object near another charged object near another uncharged object (no contact)uncharged object (no contact)

2. What occurs?: e2. What occurs?: e- - are either are either attracted or repelled from the attracted or repelled from the charged objectcharged object

3. Diagram3. Diagram

video simulation that includes how lightning works and grounding

InductionInduction4. Resulting Charge4. Resulting Charge

Resulting Charge: Resulting Charge: Opposite of charging Opposite of charging object (temporary)object (temporary)

Overall charge is still Overall charge is still neutral neutral

B. ConductionB. Conduction

1. How? Touch charged 1. How? Touch charged object to another objectobject to another object

2. What occurs? e2. What occurs? e- - are are transferredtransferred

ConductionConduction

ConductionConduction

4. Resulting Charge: 4. Resulting Charge: same charge as same charge as charging object and charging object and charge is permanentcharge is permanent

GroundingGroundingProcess of removing excess Process of removing excess

charge from an object by charge from an object by transfer of etransfer of e- - to a larger to a larger objectobject

Ex.: middle prong on wall Ex.: middle prong on wall outletoutlet

Mike is investigating the charge on Mike is investigating the charge on several objects and makes the several objects and makes the following observations: C attracts B, following observations: C attracts B, D repels C, E attracts D and repels F, F D repels C, E attracts D and repels F, F attracts A;attracts A;

If A is negatively charged and B is If A is negatively charged and B is neutral, what can Michael conclude neutral, what can Michael conclude about the charge of C, D, E, and F?about the charge of C, D, E, and F?

F is positive, E is positive, D is negative, F is positive, E is positive, D is negative, and C is negativeand C is negative

Two neutral conducting pop cans are Two neutral conducting pop cans are touching each other. A negatively touching each other. A negatively charged balloon is brought near Can charged balloon is brought near Can X as shown below. As the balloon X as shown below. As the balloon approaches Can X, there is a approaches Can X, there is a movement of electrons between the movement of electrons between the balloon and can X. balloon and can X.

a.a. TRUETRUE

b.b. FALSEFALSE

A metal sphere is electrically neutral. It is touched A metal sphere is electrically neutral. It is touched by a positively charged metal rod. As a result, the by a positively charged metal rod. As a result, the metal sphere becomes charged positively. Which metal sphere becomes charged positively. Which of the following occur during the process? List all of the following occur during the process? List all that apply.that apply.

a. The metal sphere gains some protons. a. The metal sphere gains some protons. b. Electrons are transferred from the sphere to the b. Electrons are transferred from the sphere to the

rod.rod.c. The metal sphere loses electrons.c. The metal sphere loses electrons.d. The overall charge of the system is conserved.d. The overall charge of the system is conserved.e. Protons are transferred from the rod to the sphere.e. Protons are transferred from the rod to the sphere.f. Positive electrons are moved between the two f. Positive electrons are moved between the two

objects.objects.

ReviewReview List and describe the 3 electrical List and describe the 3 electrical

states of matterstates of matter Explain the process of inductionExplain the process of induction Explain the process of conductionExplain the process of conduction What happens during grounding?What happens during grounding?