Exploring Electrical Exploring Electrical TechnologyTechnology

Era of Early Electrical ScienceEra of Early Electrical Science

Part II: “Jarring Electricity”Part II: “Jarring Electricity”

Summary of 17Summary of 17thth Century Century & Electricity& Electricity

Attempts by Jesuits to contribute to Attempts by Jesuits to contribute to understanding during this 1understanding during this 1stst Period Period

Printing Press: had been available since the Printing Press: had been available since the mid 1400s, so by 1600s many works were mid 1400s, so by 1600s many works were readily published (after ~3 years)readily published (after ~3 years)

New Inventions: telescope, microscope, time-New Inventions: telescope, microscope, time-keeping devices, thermometer, air pump, keeping devices, thermometer, air pump, various machines and use of water and wind to various machines and use of water and wind to power thempower them

Summary of 17Summary of 17thth Century Century & Electricity& Electricity

Development of patent lawsDevelopment of patent laws During the mid 1600sDuring the mid 1600s Aided in getting credit where it is dueAided in getting credit where it is due

Establishment of the first AcademiesEstablishment of the first Academies In France (1660)In France (1660) In England (1662)In England (1662)

Summary of 17Summary of 17thth Century Century & Electricity& Electricity

Humorous instances of science starting and stopping Humorous instances of science starting and stopping during this timeduring this time As an illustration, consider an observation made by Newton in As an illustration, consider an observation made by Newton in

1675 to the Royal Society of London. . .1675 to the Royal Society of London. . . Read from 1Read from 1stst selection in your coursepack @ top of p. 168 selection in your coursepack @ top of p. 168

Heilbron, J.L. Heilbron, J.L. Elements of Early Modern PhysicsElements of Early Modern Physics. Berkeley: . Berkeley: University of California Press, 1982. University of California Press, 1982.

Conclusions: less than 300 years ago, understanding Conclusions: less than 300 years ago, understanding about electricity amounted to realizing that about electricity amounted to realizing that its attractive force was different from magnetic attractionits attractive force was different from magnetic attraction it could be generated, and as a curiosity it was popular, but it could be generated, and as a curiosity it was popular, but

little progress was made in the way of theorizing about it.little progress was made in the way of theorizing about it.

Early 18Early 18thth Century Century (2(2ndnd Period: 1700-1740) Period: 1700-1740) HawksbeeHawksbee

An English instrument maker and member of An English instrument maker and member of the RSLthe RSL

In 1706* he created a special glass tubeIn 1706* he created a special glass tube A more efficient static electric generation deviceA more efficient static electric generation device Able to demo. electrostatic repulsion & attractionAble to demo. electrostatic repulsion & attraction

He did not interpret repulsion as related to He did not interpret repulsion as related to electrification (held to Cabeo’s theory)electrification (held to Cabeo’s theory)

* Note that this was the year as Ben Franklin’s birth.

Early 18Early 18thth Century Century (2(2ndnd Period: 1700-1740) Period: 1700-1740) Other notable people & developmentsOther notable people & developments

Isaac Newton, the most famous and notable Isaac Newton, the most famous and notable member of the RSL at the time, commented in 1710 member of the RSL at the time, commented in 1710 that most of the phenomena observed as a result of that most of the phenomena observed as a result of friction on glass was the effect of electric attraction, friction on glass was the effect of electric attraction, and not any other force such as repulsionand not any other force such as repulsion

The glass tube became the standard for generating The glass tube became the standard for generating electrostatic forces, and it was the type of electrostatic forces, and it was the type of instrument that Ben Franklin obtained in 1745 which instrument that Ben Franklin obtained in 1745 which stimulated his interest in electricitystimulated his interest in electricity

Early 18Early 18thth Century Century (2(2ndnd Period: 1700-1740) Period: 1700-1740) GrayGray

A dyer by tradeA dyer by trade Discovered that electricity can flow and be Discovered that electricity can flow and be

transmitted from one object to the next over transmitted from one object to the next over a distance by certain materials (conductors*)a distance by certain materials (conductors*)

Read 2 Read 2 Parag’sParag’s from Heilbron (pp. 172, 173) from Heilbron (pp. 172, 173)

Early 18Early 18thth Century Century (2(2ndnd Period: 1700-1740) Period: 1700-1740) Gray and his groupGray and his group

Began to notice the difference between materials Began to notice the difference between materials through which electricity flows easily and materials through which electricity flows easily and materials which offer opposition to electric conductionwhich offer opposition to electric conduction

Had a theory that (unfortunately) continued to Had a theory that (unfortunately) continued to confuse the mechanism of electric conduction with confuse the mechanism of electric conduction with the forces of attraction at a distancethe forces of attraction at a distance

Good “conductors”: water, an umbrella, wires & skinGood “conductors”: water, an umbrella, wires & skin Good “insulators”: glass, silk, hair and resinGood “insulators”: glass, silk, hair and resin The Charity Boy demo (see Heilbron p. 173) was a The Charity Boy demo (see Heilbron p. 173) was a

common one to show various electrical properties common one to show various electrical properties

Early 18Early 18thth Century Century (2(2ndnd Period: 1700-1740) Period: 1700-1740) Hawksbee threatened by Gray’s workHawksbee threatened by Gray’s work

Hawksbee, at the RSL, after learning of Hawksbee, at the RSL, after learning of Gray’s work, put two of Gray’s observations Gray’s work, put two of Gray’s observations forth as his own, and the rest he suppressed forth as his own, and the rest he suppressed

Motivation: his livelihood may have come Motivation: his livelihood may have come largely from his work for the RSL, and he largely from his work for the RSL, and he may have felt he could not afford to may have felt he could not afford to encourage rival experimentalistsencourage rival experimentalists

How could Hawksbee have turned Gray’s work into something more positive for himself and others?

Early 18Early 18thth Century Century (2(2ndnd Period: 1700-1740) Period: 1700-1740) Conductor and InsulatorConductor and Insulator

Not terms actually used by GrayNot terms actually used by Gray 11stst used by Desaguliers in 1739 used by Desaguliers in 1739

French English physicistFrench English physicist Also repeated many of Gray’s experimentsAlso repeated many of Gray’s experiments

Good experimental scienceGood experimental science Results testable (known procedure)Results testable (known procedure) Results repeatable (rather than incidental)Results repeatable (rather than incidental)

If a faithful and reliable God did not create all the universe and its contents then how could we expect any consistency, reliability or repeatability?

Early 18Early 18thth Century Century (2(2ndnd Period: 1700-1740) Period: 1700-1740) DufayDufay

French member of Academy of Sci. in ParisFrench member of Academy of Sci. in Paris Duplicated & confrm’d many demos by GrayDuplicated & confrm’d many demos by Gray Contributed more precise theory on phenom.Contributed more precise theory on phenom.

Proposed a “2-fluid” theory of electricityProposed a “2-fluid” theory of electricity ““Vitreous” & “resinous” elementsVitreous” & “resinous” elements Like elements repel and unlike attractLike elements repel and unlike attract

Set stage for controversy w/ Franklin’s viewSet stage for controversy w/ Franklin’s view

End of Early 18End of Early 18thth Century Century (2(2ndnd Period: 1700-1740) Period: 1700-1740) Electricity grows more popularElectricity grows more popular

In 1740, electricity was a rather small part of In 1740, electricity was a rather small part of the topics covered in public lectures, but by the topics covered in public lectures, but by 1745 it became the “rage”1745 it became the “rage”

This change creates a transition from This change creates a transition from Heilbron’s 2Heilbron’s 2ndnd to 3 to 3rdrd Period Period

Electricity entertainsElectricity entertains Heilbron p. 179, middle bottom Heilbron p. 179, middle bottom Heilbron p. 180 Practical JokesHeilbron p. 180 Practical Jokes

Mid 18Mid 18thth Century Century(3(3rdrd Period: 1740-60) Period: 1740-60)

During the early part (~1740-1745)During the early part (~1740-1745) Ben FranklinBen Franklin

Visited in Boston and again in PhiladelphiaVisited in Boston and again in Philadelphia Heard his first public lectures & demos of Heard his first public lectures & demos of

electricity by Dr. Archibald Spencer (a demo electricity by Dr. Archibald Spencer (a demo similar to Gray’s suspended charity boy)similar to Gray’s suspended charity boy)

Leiden Jar invented separately by two menLeiden Jar invented separately by two men Von Kleist (1745 in Pomeria, Poland)Von Kleist (1745 in Pomeria, Poland) Van Musschenbroek (1746 in Leiden, Holland)Van Musschenbroek (1746 in Leiden, Holland)

Mid 18Mid 18thth Century Century(3(3rdrd Period: 1740-60) Period: 1740-60)

The Leiden JarThe Leiden Jar Underscored how strong the fluid view of Underscored how strong the fluid view of

electricity had become; if a fluid, then why electricity had become; if a fluid, then why not store it like one?not store it like one?

Raised demonstrations and experiences Raised demonstrations and experiences with electricity to new heights, temporarilywith electricity to new heights, temporarily Read of experiences with the Leiden Jar from Read of experiences with the Leiden Jar from

Heilbron, pp. 184-185.Heilbron, pp. 184-185.

All this sets the stage for Ben Franklin All this sets the stage for Ben Franklin