Warm-Up 12/19/13 Draw a 3 frame cartoon strip that shows the series of events that may cause you to receive a shock from a metal door knob on a dry winter day.

20.2 Electric Current and Ohm’s Law Thursday 12/19/13

Electric Current A continuous flow of electric charge Measured in Amperes/Amps (A) There are two main types: Direct Current (DC) Alternating Current (AC)

DC AC Charge flows only in one direction Example: flashlight or battery operated device Flow of electrical charge that changes direction Example: electricity in home and school

Voltage Also known as the “potential difference” The difference in electrical potential energy between two places in an electric field CHARGE FLOWS FROM AREAS OF HIGH TO LOW CHARGE Sources of voltage: batteries, solar cells, generators

Conductors & Insulators Different types of materials are better at supporting an electric current Conductors: charge can flow easily, like in metal wires Insulators: charge can’t flow easily, like through plastic or rubber

Resistance Measures the opposition or difficulty of charge flow in a material Unit is Ohms Low resistance materials are THIN, SHORT, AND COLD High resistance materials are THICK, LONG, AND HOT

Voltage (Volts) = Current(Amps)x Resistance (Ohms) Ohm’s Law Shows the relationship between voltage, current, and resistance. You can increase voltage by increasing current or resistance V = I x R Voltage (Volts) = Current(Amps)x Resistance (Ohms)

Your Job Complete the Ohm’s Law practice problems.