electricity chapter 13. section 1 electric charge
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Electricity Chapter 13Section 1Electric ChargePositive and Negative ChargeThere are two types of electric chargeProtons have positive electric chargeElectrons have negative electric chargeWhat happens if an atom has an equal number of protons and electrons?No net electrical chargeElectrically neutralDo neutrons have an electric charge?No...neutrons are uncharged particlesThe strength of the attraction between electrons and the nucleus can vary between different types of atoms and moleculesFor ExampleElectrons are more attracted to atoms in the soles of your shoes than the atom in carpetElectrons will transfer from the carpet to your shoesWhat is the charge of the carpet now?PositiveWhat is the charge of the soles of your shoes?NegativeAn accumulation of excess electric charge is called STATIC ELECTRICITY
Transferring ChargeWhen an object becomes chargedElectrons usually moved from one object to anotherCharge cannot be created or destroyedCharge is transferredThe Law of Conservation of ChargeCharge cannot be created or destroyed, but can be transferred from object to objectConservation of ChargeThe forces that exist between charges are dependent on two thingsThe type of chargeLike charges repelOpposite charges attractThe distance between chargesForce decreases as objects move apartWhat do you think causes clothes in your dryer to be attracted to one another?Some clothes gain electrons (negatively charged)Some clothes lose electrons (positively charged)Clothes of opposite charge stick together
Charges Exert ForcesAn electric field surrounds every electric chargeThe field exerts a force causing other electric charges to be repelled or attractedAny charge in the field will be pushed or pulledElectric fields are represented by arrows that show how the field would make a positive charge behaveElectric Fields
Rememberall objects are attracted on one another by gravitational forcesElectric forces are much strongerThe electric forces between electrons and protons are what keep atoms togetherThe Strength of Electric ForcesA material in which electrons are able to move easily is a conductorWhat type of material make the best conductors?MetalsA material in which electrons are not able to move easily is an insulatorCan you think of some examples?Wood, plasticThermal insulators and conductors are not always electrical conductorsCan you think of a thermal conductor that is also an electrical conductor?MetalsCan you think of thermal conductor that is not an electrical conductor?Glass
Conductors and InsulatorsRubbing objects together can result in a transfer of electronsOne material has a positive charge and the other has negative chargeThis type of transfer is charging by contactWhen a charge object comes near a neutral objects, the electrons of the neutral object will rearrangeThe neutral object becomes chargesThis type of transfer is charging by inductionCharging ObjectsLightning is the sudden discharge of charges built up in thunderclouds.
The collisions of atoms and molecules as they move through air cause air to emit light.
Lightning also produces powerful sound waves due to the large amount of heat that causes the surround air to expand rapidly and produce thunder.
To protect objects from being stuck by lighting, they are often grounded to Earth. Grounding provides a path for lightning to travel to the ground.
How It Works: LightningLightning and Thunder
Electric charge can be detected using an electroscope
Detecting Electric Charge