19.1 Notes19.1 Notes

Atoms & ChargeAtoms & Charge Remember,Remember, all all

matter is made up matter is made up of atoms and atoms of atoms and atoms are made up of are made up of smaller particles!smaller particles!

Protons – have a Protons – have a positive chargepositive charge

Electrons – have a Electrons – have a negative chargenegative charge

Neutrons – do not Neutrons – do not have a chargehave a charge

electron

neutron

proton

Electric Charge and Electric Charge and Static ElectricityStatic Electricity

Charges can exert forces!!! Charges can exert forces!!! A charged object exerts a force (a push or a A charged object exerts a force (a push or a

pull) on other charged objects.pull) on other charged objects. THE LAW OF ELECTRIC CHARGES states that like THE LAW OF ELECTRIC CHARGES states that like

charges repel and opposite charges attract.charges repel and opposite charges attract.

Electric Charge and Electric Charge and Static ElectricityStatic Electricity

Did you know? Car Did you know? Car manufacturers take manufacturers take advantage of the advantage of the LAW OF ELECTRIC LAW OF ELECTRIC CHARGES when CHARGES when they paint cars. they paint cars. The car bodies are The car bodies are given a positive given a positive charge and the charge and the paint droplets are paint droplets are given a negative given a negative charge!charge!

Electric Charge and Electric Charge and Static ElectricityStatic Electricity

The force between charged objects is The force between charged objects is an ELECTRIC FORCE. The strength of an ELECTRIC FORCE. The strength of the force depends on the size of the the force depends on the size of the charge and the distance between charge and the distance between charges.charges.

An ELECTRIC FIELD is a region around An ELECTRIC FIELD is a region around a charged particle that can exert a a charged particle that can exert a force on another charged particle.force on another charged particle.

Electric Charge and Electric Charge and Static ElectricityStatic Electricity

Did you know Did you know that Benjamin that Benjamin Franklin Franklin introduced the introduced the terms terms positivepositive and and negativenegative as as they relate to they relate to electrical energy, electrical energy, and he invented and he invented the lightning rod.the lightning rod.

Electric Charge andElectric Charge andStatic ElectricityStatic Electricity

Objects become charged because Objects become charged because they lose or gain electrons. they lose or gain electrons.

If electrons are lost, the object If electrons are lost, the object becomes positively charged. becomes positively charged.

If electrons are gained, the object If electrons are gained, the object becomes negatively charged.becomes negatively charged.

Electric Charge andElectric Charge andStatic ElectricityStatic Electricity

There are 3 common ways for There are 3 common ways for an object to become charged:an object to become charged: FrictionFriction ConductionConduction InductionInduction

The charge on an object can The charge on an object can be detected by an be detected by an electroscope.electroscope.

Electric Charge andElectric Charge andStatic ElectricityStatic Electricity

Friction: Rubbing two Friction: Rubbing two objects together can cause objects together can cause electrons to be “wiped” from one object electrons to be “wiped” from one object

and transferred to the other.and transferred to the other. Ex: If you rub a plastic ruler with a cloth Ex: If you rub a plastic ruler with a cloth

– electrons are transferred from the – electrons are transferred from the ruler. The ruler becomes negatively ruler. The ruler becomes negatively charged and the cloth becomes charged and the cloth becomes positively charged!positively charged!

Electric Charge andElectric Charge andStatic ElectricityStatic Electricity

ConductionConduction: : Charging by Charging by conduction conduction occurs when occurs when electrons are electrons are transferred transferred from one from one object to object to another by another by direct contactdirect contact..

Electric Charge andElectric Charge andStatic ElectricityStatic Electricity

InductionInduction: Charging by induction : Charging by induction occurs when charges in an occurs when charges in an uncharged object are rearranged uncharged object are rearranged without direct contact without direct contact with a with a charged object.charged object.

Ex: A negatively charged balloon Ex: A negatively charged balloon induces a positive charge on a induces a positive charge on a small section of wall because the small section of wall because the electrons in the wall move away electrons in the wall move away from the balloon.from the balloon.

Electric Charge andElectric Charge andStatic ElectricityStatic Electricity

When you charge objects by any When you charge objects by any method, no charges are created method, no charges are created or destroyed. Electrons simply or destroyed. Electrons simply MOVE from one atom to another, MOVE from one atom to another, creating objects or areas with creating objects or areas with different charges.different charges.

Because charges are not created Because charges are not created or destroyed, CHARGE IS SAID or destroyed, CHARGE IS SAID TO BE CONSERVED.TO BE CONSERVED.