Electricity and Magnetism

CSIRO Education ACT

CSIRO.

A Historical Perspective

• Some key figures• Thales of Miletus (600BC)

• Rubs amber and documents creation of a charge• Dr William Gilbert (1600)

• Coined the word electricity from the Greek word elektron meaning amber• Robert Boyle (1675)

• Observes attraction and repulsion• Stephen Gray (1729)

• Experiments with conductors and insulators• Benjamin Franklin (1752)

• Proves that lightning and static electricity are the same• Alessandro Volta (1793)

• First batteries• Michael Faraday (1821)

• First electric motor• Thomas Edison (1878-79)

• First commercial electrical energy distribution network• Nikola Tesla (1888)

• Invents rotating field AC alternator

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What is Electricity?

• Electricity• More commonly associated with

electrical power

• Includes;• Electric charge• Electric current• Electric field• Electric potential• Electromagnetism

• How do we get it?• Fossil Fuels

• Coal, gas, diesel• Nuclear• Renewable Sources

• Wind, solar, geothermal, hydro

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Conductors and Insulators

• Conductors• Conduct electricity

• Insulators• Do not conduct electricity

• In the classroom• Testing using an open circuit with

a light or buzzer• Make a conductivity tester• Good opportunity to discuss

safety

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Static Electricity

• What is it?• Separation of negative and

positive charges

• Van der Graaf generator

• In the classroom• Balloons• Socks on carpet• Synthetic materials

• Tricks of the trade• Humidity• Discharging• Hair spray

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Electrical Current

• Alternating Current (AC)• Periodically changes direction• Is the form electrical power is

delivered to homes and businesses

• Direct Current (DC)• Flows in one direction• Used in batteries

• Affects on the body• Heart• Other muscles• Skin

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Electric Circuits

• The Jargon• Open/broken• Closed• Short• Series• Parallel

• In the classroom• Turning lights on• Interpreting circuit diagrams• CSIRO Education• Madlab

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Circuit Diagram

Battery

Speaker

Switch

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What is Magnetism?

• Magnetism• A property of materials that

respond to a magnetic field

• Magnetic Field• On Earth

• Magnetic North at South Pole• Magnetic South at North Pole• Why?

• Attraction and Repulsion• Opposites• Likes

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What materials are magnetic?

• Permanent Magnets• Iron• Nickel• Cobalt• Rare earth elements (e.g.

neodymium)

• Temporary Magnets• Electromagnets

• Copper wire coil• Magnetic field enhanced by

wrapping coil around other materials

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What materials are magnetic?

• In the classroom• Testing for magnetism• Drawing magnetic fields

• Make your own iron filings• Testing strength• Science by Email Activities

• Making a motor• Magnetic Rocket• Confusing a compass• Magnetic Sculpture• Antigrav magnets• Extracting iron from cereal• Magnetic Slime

• Tricks of the Trade• Magnets can jump• Pacemakers• Splinters

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Electromagnets

• What is it?• An electric current creates a

magnetic field• Strong magnetic field created in

the centre of the coil

• Why?• Can be switched on and off• Can vary the strength of the field

• In the classroom• Where is it used? Why?• Make your own electromagnet

• Tricks of the trade• Heat

CSIRO.

Contact UsPhone: 1300 363 400 or +61 3 9545 2176

Email: enquiries@csiro.au Web: www.csiro.au

Thank you

CSIRO Education ACTFemke MatthewsEducation Officer

Phone: 02 6246 5229Email: Femke.Matthews@csiro.auWeb: www.csiro.au/educationact