STATIC ELECTRICITY THE STUDY OF CHARGES AT REST

ACTIVITY MODEL OF AN ATOM CHARGE A BALLOON

STATIC ELECTRICITY When you rub a balloon on your hair you scrape electrons off the atoms of your hair onto the balloon.

The atoms of the balloon apparently have more “grab” on electrons.

“Laws of Attraction”

Opposite Charges Attract

+ -

Like Charges Repel

+ +

ACTIVITY STYROFOAM ELECTROSCOPE

A COULOMB THE FUNDAMENTAL UNIT OF CHARGE IT IS EQUAL TO THE CHARGE OF 6.25 BILLION BILLION ELECTRONS

COULOMBS LAW ELECTRICAL FORCE DEPENDS ON THE SIZE OF THE CHARGES AND THE DISTANCE BETWEEN THE CHARGES

Coulomb’s Law The force between charges varies inversely with the square of their separation distances.

+ + + +

COULOMB’S LAW F = k X Q 1 X Q 2 / D 2

ACTIVITY POLARIZING A STICK

Polarization Polarized objects have an uneven distribution of charge.

A polarized object has no net charge.

Meter Stick + + + + + + + + + + + + + + + + + + + +

Weak Force + + + + + + + + + + + + + + + + + + + + Strong Force -

CURRENT ELECTRICITY THE STUDY OF CHARGES IN MOTION

ELECTRICAL CIRCUIT A COMPLETE PATH FOR ELECTRON FLOW

ACTIVITY ELECTICAL ALTERNATIVES XMAS TREE BULB MAKE A WIRE

CIRCUIT WIRE CONDUCTOR INSULATOR

ELECTRICAL CIRCUIT CONSISTS OF •SOURCES OF ELECTRICAL ENERGY •A COMPLETE CONDUCTING PATH •DEVICES THAT CONVERT ELECTRICAL ENERGY TO OTHER FORMS

ACTIVITY ADDING BATTERIES MAKE A SWITCH

What is a conductor?

a material that allows free electron movement Examples:  Aluminum  Gold  Copper  All Metals

ACTIVITY GOOD CONDUCTORS POOR CONDUCTORS

What is an insulator?

a material that does not allow electrons to flow freely Examples:  Plastics  Ceramics  Amber

ACTIVITY CONDUCTIVITY TESTER

LIGHT BULB FILAMENT CONDUCTOR

ACTIVITY CREATING LIGHT

BATTERIES TERMINAL 1.5 VOLTS + TERMINAL STANDARD “D” CELL

VOLTAGE COMMON TERM FOR “POTENTIAL” THE AMOUNT OF ENERGY PER ELECTRON PRODUCED BY AN ENERGY SOURCE (BATTERY)

ELECTRICAL CURRENT THE RATE OF FLOW OF CHARGE

ELECTRICAL CURRENT THE BRIGHTNESS OF A LIGHT BULB IS A GOOD INDICATOR OF THE RELATIVE AMOUNT OF CURRENT FLOWING THROUGH IT.

ELECTRICAL CURRENT ELECTRONS FLOW OUT OF THE NEGATIVE TERMINAL OF A BATTERY.

AFTER ELECTRONS TRAVEL THROUGH THE CIRCUIT, THEY FLOW INTO THE POSITIVE TERMINAL OF THE BATTERY.

ELECTRICAL RESISTANCE RESISTANCE TO ELECTRON FLOW

ACTIVITY PENCIL LEAD DIMMER SWITCH LIGHT DIMMER

ELECTRICAL SHORT A LOW RESISTANCE PATH ACROSS THE TERMINALS OF AN ELECTRICAL CIRCUIT ELEMENT.

IF IT OCCURS ACROSS A BATTERY, GENERATOR OR ANY ENERGY SOURCE, IT CAN CAUSE TOO HIGH OF A CURRENT.

ELECTRICAL SHORT SOMETIMES A RESISTOR CAN HAVE A SHORT ACROSS ITS LEADS. IF THIS OCCURS AND ANOTHER RESISTOR IS IN THE CIRCUIT, THE OTHER RESISTOR MAY POSSESS ENOUGH RESISTANCE TO KEEP THE CURRENT FROM BECOMING TOO LARGE. WHEN THIS OCCURS, NO CURRENT WILL PASS THROUGH THE SHORTED RESISTOR.

CIRCUIT DIAGRAM A CONCISE REPRESENTATION OF AN ELECTRICAL CIRCUIT UTILIZING STANDARD ELECTRICAL SYMBOLS.

IT SHOULD BE ACCURATE, SIMPLE AND NEAT.

ACTIVITY ELECTROSQUARES DRAWING CIRCUITS

ELECTRON CURRENT A MEASURE OF THE RATE OF FLOW OF ELECTRON CHARGE THROUGH A CIRCUIT.

THE DIRECTION OF FLOW IS FROM THE NEGATIVE SIDE OF THE ENERGY SOURCE THROUGH THE CIRCUIT TO THE POSITIVE SIDE OF THE ENERGY SOURCE.

OHM’S LAW THE CURRENT THROUGH A RESISTOR IS PROPORTIONAL TO THE APPLIED VOLTAGE AND INVERSELY PROPORTIONAL TO ITS RESISTANCE.

I = V / R I = CURRENT V = VOLTAGE R = RESISTANCE

ELECTRICAL CURRENT • A MEASURE OF THE NUMBER OF COULOMBS PER SECOND THAT PASSES A POINT IN A CIRCUIT.

• THE UNIT OF CURRENT IS THE AMPERE = COULOMB PER SECOND

VOLTAGE (POTENTIAL) THE ENERGY PER CHARGE LOST OR GAINED BY CHARGES AS THEY PASS THROUGH A DEVICE.

THE UNIT IS THE VOLT = JOULE PER COULOMB

RESISTANCE A MEASURE OF THE RESISTANCE TO ELECTRON FLOW.

THE UNIT IS THE OHM = VOLT PER AMPERE SYMBOL FOR OHM IS W

RESISTANCE RESISTANCE CAN BE RELATED TO THE AMOUNT OF VOLTAGE NEEDED TO PRODUCE A AMPERE OF CURRENT.

IF IT TAKES TWO VOLTS TO PRODUCE ONE AMPERE, THE RESISTANCE IS TWO OHMS

Current, Voltage, Resistance Current  a measure of the rate of flow of electrons  measures in Amperes (A) Voltage  a measure of the energy per charge  measured in Volts (V) Resistance   a measure of the resistance to electron flow measured in Ohms ( W )

SERIES CIRCUITS THE CURRENT HAS A SINGLE PATH AROUND THE CIRCUIT

ACTIVITY SERIES CIRCUIT

CIRCUIT ELEMENTS IN SERIES ALL HAVE THE SAME CURRENT THROUGH THEM

PARALLEL CIRCUIT THE CURRENT HAS MULTIPLE PATHS AROUND THE CIRCUIT

ACTIVITY PARALLEL CIRCUITS

CIRCUIT ELEMENTS IN PARALLEL ALL HAVE THE SAME VOLTAGE ACROSS THEM

RESISTORS IN SERIES THE TOTAL RESISTANCE IS THE SUM OF ALL RESISTORS IN SERIES.

RESISTORS IN PARALLEL THIS COMBINATION POSSESSES LESS COMBINED RESISTANCE THAN THE LOWEST RESISTOR IN THE COMBINATION.

BATTERIES IN SERIES THE TOTAL VOLTAGE PRODUCED BY BATTERIES IN SERIES IS THE SUM OF THE VOLTAGES OF EACH BATTERY

BATTERIES IN PARALLEL PRODUCE THE SAME VOLTAGE

QUESTION HOW DO YOU CONNECT A BATTERY TO “JUMP START” YOU CAR?

WHY ARE BATTERIES CONNECTED IN BOTH PARALLEL AND SERIES IN SOME PORTABLE DEVICES?

ACTIVITY ELECTRIC CIRCUITS

DIODE DIODE MEANS TO CONDUCT IN ONLY ONE DIRECTION WILL CONDUCT ELECTRONS WILL NOT CONDUCT ELECTRONS

LIGHT EMITTING DIODE (LED) A DIODE THAT EMITS LIGHT WHEN CURRENT IS PRESENT.

MOST LED’S REQUIRE ONLY A MILLIAMP TO BE SEEN.

FUSE A FUSE IS PLACED IN SERIES WITH THE ENERGY SOURCE. IT IS RATED TO BURN (OR MELT) IF THE CURRENT THROUGH IT EXCEEDS ITS RATING.

ACTIVITY CIRCUIT BREAKERS

CIRCUIT BREAKER A MAGNETIC SWITCH THAT BREAKS THE CIRCUIT IF THE CURRENT IN THE CIRCUIT EXCEEDS ITS RATING

SWITCHES SINGLE POLE SINGLE THROW SINGLE POLE DOUBLE THROW

ACTIVITY MAKE A SWITCH

LEMON BATTERY THE ZINC TERMINAL IS NEGATIVE THE COPPER TERMINAL IS POSITIVE ABOUT 1 VOLT IS PRODUCED BY A SINGLE LEMON BATTERY YOU NEED TWO LEMONS TO LIGHT AN LED

ACTIVITY LIGHT AN LED USING LEMON BATTERIES