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== Description of machine ==
== Description of machine ==
[[File:Franklin machine globe.jpg|thumb|Close-up of globe that produced static electricity that charged a Leyden jar.]]
[[File:Franklin machine globe.jpg|thumb|Close-up of globe that produced static electricity that charged a Leyden jar.]]

The electrostatic machine supplied sparks to a Leyden jar so Franklin would have a source of electricity on demand. He started his experiments on electricity in the winter of 1746-1747.{{sfn|Grimnes|2014|page=495}}{{sfn|Feldman|2014|page=36}} The machine consisted of a rotating glass globe and a piece of [[Chamois leather|chamois leather]] in the form of a pad. The globe turned because of a leather belt that was attached to a larger cranked wooden wheel. The globe built up an electric charge since it rubbed against the chamois pad causing an excess of electrons and an electrical charge. A set of connected metal knitting needles then just barely touched the charged globe which caused sparks. The electricity was passed through a metal link to the Leyden jar, charging it.{{sfn|Feldman|2014|page=36}} Franklin then did electrical experiments with this continual supply of electricity that could be made on demand from static charges that developed on the glass globe when it turned and rubbed against the chamois pad.{{sfn|Fleming|2014|page=49}}{{sfn|Van Vleet|2007|page=98}}
The electrostatic machine supplied sparks to a Leyden jar so Franklin would have a source of electricity on demand. He started his experiments on electricity in the winter of 1746-1747.{{sfn|Grimnes|2014|page=495}}{{sfn|Feldman|2014|page=36}} The machine consisted of a rotating glass globe and a piece of [[Chamois leather|chamois leather]] in the form of a pad. The globe turned because of a leather belt that was attached to a larger cranked wooden wheel. The globe built up an electric charge since it rubbed against the chamois pad causing an excess of electrons and an electrical charge. A set of connected metal knitting needles then just barely touched the charged globe which caused sparks. The electricity was passed through a metal link to the Leyden jar, charging it.{{sfn|Feldman|2014|page=36}} Franklin then did electrical experiments with this continual supply of electricity that could be made on demand from static charges that developed on the glass globe when it turned and rubbed against the chamois pad.{{sfn|Fleming|2014|page=49}}{{sfn|Van Vleet|2007|page=98}}
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Another principle he proved from the experiments of his electrostatic machine was that lightning is a giant electric spark.<ref name=Britannica>
Another principle he proved from the experiments of his electrostatic machine was that lightning is a giant electric spark.<ref name=Britannica>
{{cite encyclopedia |last=Chisholm |first=Hugh |author-link= |editor-last= |editor-first= |editor-link= |encyclopedia=The Encyclopædia Britannica |title= Electricity|trans-title= |url=https://books.google.com/books?id=Ek80AQAAMAAJ&pg=PA181&dq=electrostatic+machine+supplied+sparks+%22Leyden+jar%22++Franklin&hl=en&sa=X&ved=0CEMQ6AEwBmoVChMIxYCW4YvixgIVQw2SCh3oaQZp#v=onepage&q=electrostatic%20machine%20supplied%20sparks%20%22Leyden%20jar%22%20%20Franklin&f=false |access-date= |language= |edition=12 |date= |year=1910 |publisher=Encyclopædia Britannica Company|series= |volume=9 |location= |id= |isbn= |oclc= |doi= |pages=181 |quote= |ref=}} </ref> He showed this by charging a Leyden jar during a lightning storm in 1752 in Philadelphia during his famous kite experiment.{{sfn|Grimnes|2014|page=495}} He showed in the kite experiment that lightning charged the Leyden jar, just like his electrostatic machine did and both of these were the same type of electricity.{{sfn|Grimnes|2014|page=495}}{{sfn|Cajori|1917|pages=121-134}} Franklin produced his lightning rod invention from that concept.{{sfn|Radmanesh|2005|page=231}}{{sfn|Coulson|1950|page=32}} He figured out then to put a pointed iron rod at roof tops to protect a building or house as the electrical discharge from the cloud would hit the rod instead and go directly down to the ground.{{sfn|Radmanesh|2005|page=231}}{{sfn|Grimnes|2014|page=496}}
{{cite encyclopedia |last=Chisholm |first=Hugh |author-link= |editor-last= |editor-first= |editor-link= |encyclopedia=The Encyclopædia Britannica |title= Electricity|trans-title= |url=https://books.google.com/books?id=Ek80AQAAMAAJ&pg=PA181&dq=electrostatic+machine+supplied+sparks+%22Leyden+jar%22++Franklin&hl=en&sa=X&ved=0CEMQ6AEwBmoVChMIxYCW4YvixgIVQw2SCh3oaQZp#v=onepage&q=electrostatic%20machine%20supplied%20sparks%20%22Leyden%20jar%22%20%20Franklin&f=false |access-date= |language= |edition=12 |date= |year=1910 |publisher=Encyclopædia Britannica Company|series= |volume=9 |location= |id= |isbn= |oclc= |doi= |pages=181 |quote= |ref=}} </ref> He showed this by charging a Leyden jar during a lightning storm in 1752 in Philadelphia during his famous kite experiment.{{sfn|Grimnes|2014|page=495}} He showed in the kite experiment that lightning charged the Leyden jar, just like his electrostatic machine did and both of these were the same type of electricity.{{sfn|Grimnes|2014|page=495}}{{sfn|Cajori|1917|pages=121-134}} Franklin produced his lightning rod invention from that concept.{{sfn|Radmanesh|2005|page=231}}{{sfn|Coulson|1950|page=32}} He figured out then to put a pointed iron rod at roof tops to protect a building or house as the electrical discharge from the cloud would hit the rod instead and go directly down to the ground.{{sfn|Radmanesh|2005|page=231}}{{sfn|Grimnes|2014|page=496}} Before Franklin's discovery it was thought that Lightning and thunder was some form of exploding gases.{{sfn|Baigrie|2007|page=40}}


''Franklin currents'' is electrostatic electricity and of his namesake.{{sfn|Grimnes|2014|page=496}} "Franklinization" is [[electrotherapy]] where Franklin applied strong static charges, from powerful Leyden jars that were charged from his electrostatic machine, to treat patients of various illnesses.{{sfn|Schiffer|2003|pages=136, 137}}<ref name=Americana>
''Franklin currents'' is electrostatic electricity and of his namesake.{{sfn|Grimnes|2014|page=496}} "Franklinization" is [[electrotherapy]] where Franklin applied strong static charges, from powerful Leyden jars that were charged from his electrostatic machine, to treat patients of various illnesses.{{sfn|Schiffer|2003|pages=136, 137}}<ref name=Americana>
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===Sources===
===Sources===

*{{cite book |last=Baigrie|first=Brian Scott |date=2007 |title=Electricity and Magnetism: A Historical Perspective |url= |location= |publisher=Greenwood Publishing Group |page= |isbn=0313333580 |access-date= |ref=harv}}


*{{cite book |last=Cajori|first=Florian |date=1917 |title=A History of Physics in Its Elementary Branches: Including the Evolution of Physical Laboratories |url= |location= |publisher=Macmillan |page= |isbn= |access-date= |ref=harv}}
*{{cite book |last=Cajori|first=Florian |date=1917 |title=A History of Physics in Its Elementary Branches: Including the Evolution of Physical Laboratories |url= |location= |publisher=Macmillan |page= |isbn= |access-date= |ref=harv}}

Revision as of 12:38, 17 July 2015

Franklin's electrostatic machine

Franklin's electrostatic machine is a high voltage static electricity generating device that was used by Benjamin Franklin for research in the mid-eighteenth century. Experiments from it eventually lead to the invention of the lightning rod and new theories about electricity.

Benjamin Franklin

Main article: Benjamin Franklin § electricity

One problem Benjamin Franklin had in doing electrical experimentation was getting a good supply of electricity. He knew of the concept that if certain objects were rubbed together they would produce a spark of electricity for a second and that was about it. He needed a source of electricity a little longer than this to do experimental research.[1]

Peter Collinson, a wealthy businessman from London, donated a Leyden jar rechargeable storage battery to Franklin's Library Company of Philadelphia in 1746. Franklin wrote a letter to him on March 28, 1747, thanking him for the Leyden jar. He pointed out that this battery and the directions of operation that came with it motivated him and several of his colleges to get excited about doing serious electrical experimentation.[2] Franklin advanced the principle of generating a spark of electricity and went about to develop an electrostatic machine to continually generate electrical sparks for a supply of electricity stored by a Leyden jar.[3]

Description of machine

Close-up of globe that produced static electricity that charged a Leyden jar.

The electrostatic machine supplied sparks to a Leyden jar so Franklin would have a source of electricity on demand. He started his experiments on electricity in the winter of 1746-1747.[4][5] The machine consisted of a rotating glass globe and a piece of chamois leather in the form of a pad. The globe turned because of a leather belt that was attached to a larger cranked wooden wheel. The globe built up an electric charge since it rubbed against the chamois pad causing an excess of electrons and an electrical charge. A set of connected metal knitting needles then just barely touched the charged globe which caused sparks. The electricity was passed through a metal link to the Leyden jar, charging it.[5] Franklin then did electrical experiments with this continual supply of electricity that could be made on demand from static charges that developed on the glass globe when it turned and rubbed against the chamois pad.[3][6]

Electrical principles

Lighting rod

An electrical principle that Franklin proved with his electrostatic machine was that of conservation of charge - that "positive" and "negative" charges come out in even amounts and are always balanced.[7] He was the first to use the terms "positive" and "negative" ("plus" and "minus") as applied to electricity. From his experiments with his electrostatic machine he developed the term "electric battery" from a bank of connected Leyden jars. He devised the theory from this that electricity is a single "fluid" that is in all matter.[8][9]

Another principle he proved from the experiments of his electrostatic machine was that lightning is a giant electric spark.[10] He showed this by charging a Leyden jar during a lightning storm in 1752 in Philadelphia during his famous kite experiment.[4] He showed in the kite experiment that lightning charged the Leyden jar, just like his electrostatic machine did and both of these were the same type of electricity.[4][11] Franklin produced his lightning rod invention from that concept.[9][12] He figured out then to put a pointed iron rod at roof tops to protect a building or house as the electrical discharge from the cloud would hit the rod instead and go directly down to the ground.[9][13] Before Franklin's discovery it was thought that Lightning and thunder was some form of exploding gases.[14]

Franklin currents is electrostatic electricity and of his namesake.[13] "Franklinization" is electrotherapy where Franklin applied strong static charges, from powerful Leyden jars that were charged from his electrostatic machine, to treat patients of various illnesses.[15][16]

References

Notes

  1. ^ "Benjamin Franklin". Complete Dictionary of Scientific Biography. 2008. Retrieved July 16, 2015.
  2. ^ "From Benjamin Franklin to Peter Collinson, 28 March 1747". Founders Online. National Historical Publications and Records Commission. Retrieved July 15, 2015.
  3. ^ a b Fleming 2014, p. 49.
  4. ^ a b c Grimnes 2014, p. 495.
  5. ^ a b Feldman 2014, p. 36.
  6. ^ Van Vleet 2007, p. 98.
  7. ^ Labaree 1961, p. 142.
  8. ^ Warkentin-Glenn 2006, p. 86.
  9. ^ a b c Radmanesh 2005, p. 231.
  10. ^ Chisholm, Hugh (1910). "Electricity". The Encyclopædia Britannica. Vol. 9 (12 ed.). Encyclopædia Britannica Company. p. 181.
  11. ^ Cajori 1917, pp. 121–134.
  12. ^ Coulson 1950, p. 32.
  13. ^ a b Grimnes 2014, p. 496.
  14. ^ Baigrie 2007, p. 40.
  15. ^ Schiffer 2003, pp. 136, 137.
  16. ^ "Electro-therapeutics". The Encyclopedia Americana: A universal reference library comprising the arts and sciences. Scientific American Compiling Department. 1905.

Citations

Sources

  • Baigrie, Brian Scott (2007). Electricity and Magnetism: A Historical Perspective. Greenwood Publishing Group. ISBN 0313333580. {{cite book}}: Invalid |ref=harv (help)
  • Cajori, Florian (1917). A History of Physics in Its Elementary Branches: Including the Evolution of Physical Laboratories. Macmillan. {{cite book}}: Invalid |ref=harv (help)
  • Coulson, Thomas (1950). Joseph Henry, his life and work. Princeton University Press. The atmosphere of Philadelphia gave him and his associates exceptional opportunity to exercise their skill with the electrostatic machine. As a result, many of their experiments were of an original character. The famous kite experiment enabled the Philadelphia group to established what had been surmised by others, that lightning was identical to the mild charge of electricity produced by the friction of the electrostatic machine. Franklin invented the lightning rod, which goes down in history as the first practical electrical invention. {{cite book}}: Invalid |ref=harv (help)
  • Feldman, Eve B (2014). Benjamin Franklin: Scientist and Inventor: Scientist and Inventor. StarWalk Kids Media. {{cite book}}: Invalid |ref=harv (help)
  • Fleming, Candace (2014). Ben Franklin's Almanac: Being a True Account of the Good Gentleman's Life. Simon and Schuster. ISBN 1481417991. {{cite book}}: Invalid |ref=harv (help)
  • Grimnes, Sverre (2014). Bioimpedance and Bioelectricity Basics. Academic Press. ISBN 0124115330. {{cite book}}: Invalid |ref=harv (help)
  • Radmanesh, Matthew M. (2005). The Gateway to Understanding: Electrons to Waves and Beyond. AuthorHouse. ISBN 1418487406. By charging a Leyden jar during a thunderstorm, Franklin and his son demonstrated that lightning and electricity (as produced by an electrostatic machine) are identical. He put his knowledge to work and invented lightning rods on roof tops to dissipate the thunder-cloud charge gradually and harmlessly to ground. {{cite book}}: Invalid |ref=harv (help)
  • Schiffer, Michael B. (2003). Draw the Lightning Down: Benjamin Franklin and Electrical Technology in the Age of Enlightenment. University of California Press. ISBN 0520238028. {{cite book}}: Invalid |ref=harv (help)
  • Van Vleet, Carmella (2007). Amazing BEN FRANKLIN Inventions: You Can Build Yourself. Nomad Press. ISBN 1619301253. {{cite book}}: Invalid |ref=harv (help)
  • Warkentin-Glenn, Denise (2006). Electric Power Industry in Nontechnical Language. PennWell Books. ISBN 1593700679. {{cite book}}: Invalid |ref=harv (help)
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