ElectrostaticsElectrostatics

ElectrostaticsElectrostatics

A.A. Definition:Definition: The study of electric charges that can be The study of electric charges that can be

collected and held in one placecollected and held in one place Non-moving, no flowNon-moving, no flowB. Examples of static chargesB. Examples of static charges Clothes in dryerClothes in dryer Rubbing feet on carpetRubbing feet on carpet Rubbing balloon on headRubbing balloon on head Dry air & hairDry air & hair

ElectrostaticsElectrostatics

C. Electric Conditions (States of Matter)C. Electric Conditions (States of Matter)1. 1. NeutralNeutral: # of neg. charges = # of pos. : # of neg. charges = # of pos. chargescharges2. 2. Negatively ChargedNegatively Charged: excess of : excess of electrons (eelectrons (e-- added to atom), more neg. added to atom), more neg. chargescharges3. 3. Positively ChargedPositively Charged: deficiency in e: deficiency in e--, , they have been stripped awaythey have been stripped away

ElectrostaticsElectrostatics

*** Special Note: *** Special Note: The electron is responsible for The electron is responsible for understanding all electrical phenomenaunderstanding all electrical phenomena

D. Rules of ChargeD. Rules of Charge1. like charges repel1. like charges repel2. opposite charges attract2. opposite charges attract3. in electrostatics, charge isn’t created, it’s 3. in electrostatics, charge isn’t created, it’s simply transferredsimply transferred

ElectrostaticsElectrostaticsClasses of Matter (electrically speaking)Classes of Matter (electrically speaking)

A. ConductorsA. Conductors1. atomic level picture 1. atomic level picture 2. Description – a material 2. Description – a material that readily transfers athat readily transfers a charge, echarge, e-- are free to move are free to move around in crystal latticearound in crystal lattice

***Known as “Sea of Electrons”***Known as “Sea of Electrons”3. Examples – metal, water, our bodies, Earth & its 3. Examples – metal, water, our bodies, Earth & its atmosphere (best)atmosphere (best)

ElectrostaticsElectrostatics

B. InsulatorsB. Insulators1. Description – electrons are tightly bound 1. Description – electrons are tightly bound

to nucleus, not free to moveto nucleus, not free to move2. Examples – plastic, wood, glass, rubber, 2. Examples – plastic, wood, glass, rubber,

paperpaperC. Semi-conductorsC. Semi-conductors

1. electrons can move, but not as free as 1. electrons can move, but not as free as conductorsconductors

2. silicon, germanium2. silicon, germanium

ElectrostaticsElectrostatics

How an object can become chargedHow an object can become chargedA. Induction:A. Induction:

1. How is it done? bring a charged object 1. How is it done? bring a charged object nearnear another uncharged object (but never touch) another uncharged object (but never touch)

2. What occurs? electrons are either 2. What occurs? electrons are either attracted or repelled from the side near charged attracted or repelled from the side near charged objectobject

ElectrostaticsElectrostatics

Induction (continued)Induction (continued)3. Diagram:3. Diagram:

4. Resulting charge – 4. Resulting charge – charges separated,charges separated, but overall charge isbut overall charge is still neutral.still neutral.

ElectrostaticsElectrostatics

B. Conduction:B. Conduction:1. How is it done? 1. How is it done? touchtouch charged object to charged object to another objectanother object

2. What occurs? electric charge (e2. What occurs? electric charge (e--) are ) are transferred to objecttransferred to object

ElectrostaticsElectrostaticsConduction (continued)Conduction (continued)

3. Diagram – (3 steps)3. Diagram – (3 steps)

4. 4. Resulting Charge – same as charge on rodResulting Charge – same as charge on rod

GroundingGrounding

Process of removing excess charge from Process of removing excess charge from an object by transfer of ean object by transfer of e- - to a larger to a larger object.object.

Ex.: middle prong on wall outletEx.: middle prong on wall outlet