Electricity Physical Science Chapter 16 Electricity Basics Electricity

Electricity Physical Science Chapter 16

Electricity Basics � Electricity is caused by the flow (or net movement) of Electrons � Electric Current – the rate that positive charges flow in a circuit › Actually a measure of the rate that negatively charged electrons move �Electrons Will Move From Higher To Lower Potential

Electric Current � Measured in Amperes (A) › Ampere = 1 Coulomb of charge per second � Voltage or Potential Difference – measure of potential energy (in Joules) › Voltage occurs across the two terminals of a battery and range from 1. 5 V for a small battery to 12 V for a car battery › Voltage sets charge in motion �Electrons move from the negative terminal to the positive terminal

Resistance � Resistors oppose the rate of charge flow in the circuit � Caused by internal friction � The resistance of the filament of a light bulb determines how bright the bulb is › Example: 4 o Watt bulb has a higher resistance than a 100 Watt bulb › Resistance = Voltage / Current �Unit - Ohms

Conductors vs. Insulators � Conductors – allow electrons to flow easily › Contain a lot of free electrons › Offer Little Resistance To Current Flow › Good Conductors �Metals (copper, gold, silver, aluminum) �Electrolyte Solutions � Insulators – do not allow electrons to flow easily or at all › Contain Few Free Electrons › Insulator Materials �Air, Wood, Glass

Relationship of Current to Potential Difference � As Current Increases – Potential Difference (Volts) Increase � As Current Increases – Resistance Decreases

Circuits � Circuit – bulb, battery, and wires › Closed Circuit – completed path – electricity flows › Open Circuit – not a complete path – no current › Parallel Circuit – multiple path for a circuit › Series Circuit – one path for a circuit