Electricity
Static charges are caused by the movement of electrons
Electric charge is a property of matter
Materials affect charge movement
Electric charge-- property that allows an object to exert an electric force on another onject without touching it.
Electric field--- The strength of the field is greater near the perticle and weaker farther away.
Static charge--- Buildup in electric charge of an object caused by the prescence of many particles with the same charge.
Charging by contact--- when charged objects with opposite charges touch each other and attract.
How Materials Affect Static Charging--- Charging by contact happens when one material's electrons are attracted to another material more than their own.
Charging by induction
Induction-- Buildup of a charge without direct contact
Charge Polarization- Objects can become polarized if they are touching another object.
Static charges have potential energy
Electric Potential Energy
Electric Potential
Electric potential is the amount of electric potential energy per unit charge at a certain position in an electric field.
Volt-- A potential of one volt is equal to one joule of energy per coulomb of charge.
Electric potential energy is stored energy an object may have because of its position.
Charge Movement
Ex: When you walk across a rug, charge builds up, and when you touch a doorknob, that charge transfers to the doorknob. This is why you get shocks.
Lightning-- A high-energy static discharge.
Conductors and Insulators
Resistance
A material that allows an electric charge to pass through it easily is called a conductor.
A material that does not easily allow a charge to pass through it is called an insulator.
Ohms-- Electrical resistance is measured in ohms.
Resistance-- Electrical resistance is the property of a material that determines how easily a charge can move through it.
Superconductors
Superconductors-- materials that have practically no resistance at extremely low temperatures.
Grounding-- providing a harmless, low-resistance path-- a ground-- for electricity to folllow.
Electric charge can flow continuously
Another name for a flow of charge is an electric current
Current, Voltage, and Resistance
Standard unit of measure for current-- ampere
Ohm's Law-- Relationship between volts, ohms, and amps.
Measuring Electricity
Electricity can be measured using instruments.
Electric cells supply electric current.
Electric cells produce electric current using other materials.
Electrochemical Cells-- electric cell that produces current by means of chemical reactions.
Solar Cells
Solar panels produce energy from the sun for people to use in their everyday lives.