Electricity and Magnetism

Chapter 5

Great Idea:Electricity and magnetism are two different aspects of one force—the

electromagnetic force

Chapter Outline

• Nature’s Other Forces• Magnetism• Batteries and Electric Circuits• Connections Between Electricity and Magnetism

• Electrical Effects from Magnetism

Nature’s Other Forces

Static Electricity

• Newton’s first law• Greeks’ observations

– Electrical charge

• Electricity– Static electricity– Properties

Static Electricity

Two Kinds of Electrical Charges

Science in the Making

• Benjamin Franklin and the electrical charge

The Movement of Electrons

• Atomic structure• Electrical charge

– Positive– Negative

• Behavior

Electrons Removed from Hair

Coulomb’s Law

• Coulomb– Experiments

• Coulomb’s Law:

– Force is related to charge and distance

• 1 Coulomb = 6.3 x 1018 electrons

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The Electrical Field

• The force felt by a charge located at a particular point

An Electrical Field Surrounding a Positive Charge

Magnetism

Magnetism

• Magnetic force• William Gilbert

– Dipole magnet– Like repels, unlike attracts

• Magnetic field

A Compass Needle and Earth

The Curving Lines of a Magnetic Field

A Bar Magnet and Its Dipole Field

The Aurora Borealis

The Science of Life

• Magnetic navigation

Pairs of Poles

• No isolated magnetic poles

Batteries and Electric Circuits

The Science of Life

• Luigi Galvani and life’s electrical force

What was behind Frankenstein?

Batteries and Electrical Current

• Electrical current– Flow of charged particles

• Battery– Alessandro Volta– Converts chemical energy to kinetic energy

Electric Circuits

• Electric circuit– Unbroken path of material carrying electricity

– Electrical conductor

• Circuit– Source– Closed path– Device to use electrical energy

Electrical Circuits

Multimeter

Ohm’s Law

• Flow of electricity– Ampere

•1 amp = 1 coulomb/sec– Voltage

•Amount of power in circuit– Electrical resistance

•Ohm

Ohm’s Law – cont.

• Ohm’s Law– Current is directly proportional to voltage and inversely proportional to resistance

– Equation: V = I x R

• Load– Equation: P = I x V

Lightning Strikes

Terms Relating to Electric Currents

The Science of Life

• The propagation of nerve signals

Two Kinds of Electric Circuits

• Series circuit vs. parallel circuit

Connections between Electricity and Magnetism

Magnetic Effects from Electricity

• Oersted– Magnetic field created by electrical charges

• Electromagnet• Magnetic monopole

– Do not exist– Arrangement of electrical charges

Schematic Drawing of an Electromagnet

Electromagnets inside the Disk Drive of a Computer

Technology

• The Electric Motor

The Science of Life

• Magnetic resonance

Electrical Effects from Magnetism

Electrical Effects from Magnetism

• Michael Faraday– Electromagnetic induction– Electrical fields and currents can be produced by changing magnetic fields

• Electric generator

Electromagnetic Induction

Electric Generator

Science in the Making

• Michael Faraday