Exploring Electrical Exploring Electrical TechnologyTechnology

1919thth Century Electrical S&T Century Electrical S&T

““The Age of Electricity”The Age of Electricity”

Allessandro Volta’s Allessandro Volta’s Career & ContributionCareer & Contribution

Professor of Physics at PaviaProfessor of Physics at Pavia Reputation of his work Reputation of his work

Advocated exact measurements of electricity Advocated exact measurements of electricity

encarta.msn.com/.../count_alessandro_volta.html

Luigi Galvani’s RoleLuigi Galvani’s Role

Accidentally found disembodied frog Accidentally found disembodied frog legs became electrically excited legs became electrically excited

Galvani’s subsequent publication in Galvani’s subsequent publication in 1791 stimulated Volta’s reaction1791 stimulated Volta’s reaction

commons.wikimedia.org/wiki/File:Luigi_Galvani...

www.alchemical.org/em/Handout10-LuigiGalvani.html

Voltaic PileVoltaic Pile

Invented by Volta in 1799Invented by Volta in 1799 Announced in 1800Announced in 1800 Why was it so significant?Why was it so significant?

Volta & his pile ushered in the Volta & his pile ushered in the “Age of Electricity” “Age of Electricity”

www.wired.com/.../news/2008/03/dayintech_0320

commons.wikimedia.org/wiki/File:Pile_de_Volta.jpg

Immediate Applications of Immediate Applications of Volta’s “Battery”Volta’s “Battery”

Nicholson & Carlisle discovered electrolysisNicholson & Carlisle discovered electrolysis A way to liberate hydrogen (H) A way to liberate hydrogen (H)

and oxygen (O) from water (H and oxygen (O) from water (H22O)O)

Enabled isolation of several active Enabled isolation of several active metal elements for 1 metal elements for 1stst time time

Became method of measuring Became method of measuring amount of chargeamount of charge

www.daviddarling.info/encyclopedia/H/history_...

Voltaic Pile Helps Voltaic Pile Helps Challenge Traditional NotionChallenge Traditional Notion

Distinction: electricity versus magnetismDistinction: electricity versus magnetism

One explorer set out to disprove itOne explorer set out to disprove it

Hans Christian Oersted Hans Christian Oersted (1777-1851)(1777-1851) & His Contribution & His Contribution

Danish physicist & chemistDanish physicist & chemist Prof. at Univ. of Copenhagen (1806)Prof. at Univ. of Copenhagen (1806) During an evening lecture in April 1820During an evening lecture in April 1820

www.aps.org/.../200807/physicshistory.cfm

http://www.youtube.com/watch?v=Zfv-0bQtqaE

Oersted’s ContributionOersted’s Contribution

Significance:Significance:

Published his finding that year (1820)Published his finding that year (1820)

Other Contemporaries of Other Contemporaries of Michael FaradayMichael Faraday

AragoArago

Andre-Marie Ampere (1775-1836)Andre-Marie Ampere (1775-1836)people.clarkson.edu/~ekatz/scientists/arago.html

people.clarkson.edu/~ekatz/scientists/ampere.htm

Other Contemporaries of Other Contemporaries of Michael FaradayMichael Faraday

Ampere’s contributionsAmpere’s contributions

Other Contemporaries of Other Contemporaries of Michael FaradayMichael Faraday

Ampere’s Career & PersonalityAmpere’s Career & Personality

Other Contemporaries of Other Contemporaries of Michael FaradayMichael Faraday

Ampere’s follow up on OerstedAmpere’s follow up on Oersted

Also worked with AragoAlso worked with Arago

Other Contemporaries of Other Contemporaries of Michael FaradayMichael Faraday

Ampere’s legacyAmpere’s legacy Published work in 1827Published work in 1827

Credited for the unit of electric current [Amp]Credited for the unit of electric current [Amp]

Ampere’s interest contrasted with othersAmpere’s interest contrasted with others

Other Contemporaries of Other Contemporaries of Michael FaradayMichael Faraday

SchweiggerSchweigger

While static electricity (i.e., frictional) had While static electricity (i.e., frictional) had been the focus of attention through the been the focus of attention through the 1818thth century, Volta’s Pile and century, Volta’s Pile and Schweigger’s galvanometer sparked Schweigger’s galvanometer sparked interest in the galvanic (dc) circuit interest in the galvanic (dc) circuit

http://en.wikipedia.org/wiki/Johann_Salomo_Christoph_Schweigger

Other Contemporaries of Other Contemporaries of Michael FaradayMichael Faraday

Georg Ohm: one of those who turned his Georg Ohm: one of those who turned his attention to the dc circuitattention to the dc circuit

www.magnet.fsu.edu/.../pioneers/ohm.html

Other Contemporaries of Other Contemporaries of Michael FaradayMichael Faraday

Others who worked on fundamental formulations Others who worked on fundamental formulations (electro- & magneto- statics) by extension of (electro- & magneto- statics) by extension of Coulomb’s workCoulomb’s work Poisson (France) – Poisson’s EquationPoisson (France) – Poisson’s Equation

Gauss (Germany) – Gauss’s LawGauss (Germany) – Gauss’s Law

Significance: concise formulation of these “laws Significance: concise formulation of these “laws of nature” concerning electricity facilitated of nature” concerning electricity facilitated description, communication & applicationdescription, communication & application

Emergence of ElectromagnetsEmergence of Electromagnets

William Sturgeon (England)William Sturgeon (England)

Joseph Henry (United States)Joseph Henry (United States)

www.todayinsci.com/5/5_22.htm

commons.wikimedia.org/wiki/File:Joseph_Henry_...

Henry Helped Others Get CreditHenry Helped Others Get Credit

His electromagnet later led to the relayHis electromagnet later led to the relay

Discovered dynamo shortly before Discovered dynamo shortly before Faraday, but…Faraday, but…

Focus on FaradayFocus on Faraday “ “Father of Electricity” ?Father of Electricity” ? Greatest scientific experimentalist of his timeGreatest scientific experimentalist of his time

faraday.physics.utoronto.ca/PHY100F/emhist.htm