So completely has the work of Georg Simon Ohm merged into the general knowledge that we lose sight of Ohm the man, his life and the story of of how his great discovery came to be.
Georg Simon Ohm, Nationality a German and a Westman.
Born: 16th March 1780
Died 6 July 1854
To set the historical background it is instructive to note that the French revolution took place in 1789. followed by the Napoleonic wars lasting from 1799 through 1815. In 1813 the Bavarian city of Erlangen, with a population 8,000 welcomed 33,000 billeted troops in anticipation of war or civilwar. It was a turbulent period in the history of our people.
In 1764 the Ohm family settled in the Bavarian city of Erlangen. Georg Ohm’s father as his grandfather before him was a locksmith. Georg Simon was the first of 7 children born to Johann Wolfgang Ohm and Maria Elizabeth Beck. Georg Simon’s mother died when he was 10 years old. Of the 7 children only 3 survived childhood. Georg Simon, his brother Martin and sister Elizabeth. Life was harsh.
Georg Simon’s father, Johann was a man of exceptional ability. During his travels performing locksmithing he managed to teach himself advanced mathematics, physics, chemistry and philosophy. While the children were young Johann taught them at home. Yes, the discoverer of the fundamental relationship governing electric current flow, was homeschooled.
In 1805, at 25 years of age, Ohm entered the University of Ehrlangen but got caught up in the University party scene and spent most of his time in activities other than his studies. Or did he? The historical record is not clear here as some sources say he had to leave the University after 3 semesters due to lack of funds. I believe it was for lack of funds. Ohm posesed too high degree of self discipline and personal motivation to be distracted by frivolities. At any rate he moved to Gottstadt, Switzerland where he found employment as a math tutor and continued his own private studies where he read the works of Euler, LaPlace, Fourier, Lagrange and LaCroix, to name just a few.
In April of 1811 he returned to the University of Erlangen. His private studies and high Westman IQ stood him in good stead as he received a Doctor of Philosophy Degree only 6 months later.
Take a step back and think about this. Homeschooled by his father and studying privately he acquired the knowledge to receive a doctorate degree. And he did it all the while tutoring to make a meager living.
His dream was to be a full professor but no positions were available. He joined the staff at the University as a lecturer in mathematics. But the wages were meager, poverty level. From the University of Erlangen he took a Bavarian government sponsored post teaching mathematics at school of questionable quality in Bamberg. In 1817 he was offered a position teaching mathematics and physics at the Jesuit Gymnasium in Cologne. Fortuitously, this school had a very well equipped physics laboratory. While lecturing at the school Ohm also continued to study privately as well as begin performing his own experimental investigations using the Gymnasium’s physics laboratory.
In 1820 ohm learned of Oersted’s discovery that an electric current would affect a compass needle. He immediately began to investigate this new phenomena. It is hard grasp now but at the time the relations and facts we take for granted about the simplest electric circuit were yet to be discovered and understood. At the time it was thought that possibly static electricity was of a different type or essence than the electricity of a galvanic circuit. It was believed that the current in a galvanic circuit was independent of the tension, tension is what we today would call voltage or electromotive force. This was due to an error on the part of Ampere. When Ampere placed 2 voltaic piles, that is batteries, in series he noted that the deflection of a compass needle was the same as with a single voltaic pile. His conclusion was that the current through a wire was independent of the voltage. This became the settled science of the day that Ohm had to over come. What Ampere failed to realize was that the primitive voltaic piles of the time had considerable internal resistance swamping the resistance of any short length of wire that might be connected across the pile. So when 2 piles were connected in series the resistance was doubled and the current as evidenced by a compass needle deflection stayed the same. But Ampere, nor anyone else at the time realized this.
Before Ohm the quantitative characteristics of the electric current had been described, in a vague imprecise way, by the use of terms such as intensity and quantity, to which no accurately defined meaning was attached. Ohm's genius was in introducing and defining the accurate notions of electromotive force , current strength , and resistance. He demonstrated their relationship through experiment, and stated his famous law that the electromotive force divided by the resistance is equal to the strength of the current.
Back in the Gynasium lab Ohm began his investigations using using a zinc copper voltaic pile with dilute sulfuric acid as the electrolyte. To measure current he built a Coulomb torsion balance and hung a magnitized needle from a thin torsion wire. The current carrying wire ran under the magnetized needle. The needle was first aligned with the Earth’s magnetic filed and the current carrying wire run parallel to the needle. Current was passed through 6 different lengths of wire ranging from 1ft to 75 feet and the needle deflection measured. It was assumed that the amount of needle deflection was proportional to the strength of the current. Ohm graphed the results.
But the voltaic pile was problematic, migrating gases, the changing polarization of the electrolyte, caused the pile voltage to be unstable. To account for these variations Ohm measured the open circuit voltage before and immediately after every test. Ohm published his results in 1825, they were tentative and because of the stability issues with the voltaic pile only hinted at the relationship that would later become known as Ohm’s law. Ohm’s paper was published in German, in, The Annals of Physics and Chemistry, edited by Dr. Christian Poggendorff. Poggendorff suggested in a footnote to the paper that the author try using the thermo-electric current generator invented by the Englishman Thomas Seebeck. Poggendorff thought this device more stable than the voltaic pile. The thermo-electric generator develops a small but steady current when dissimilar metals are in contact and when their opposite surfaces are exposed to a temperature differential. Today we commonly refer to this as a thermocouple.
Ohm was at an impasse, furthermore he got word of similar experiments performed by Henri Bequerel and Peter Barlow. Bequerel, Barlow and Ohm’s experiments all suffered from the instability of the voltaic pile and all obtained wildly different results. Ohm wrote, “these experiments are not free from interference by forces which in no way concern the matter in question”. As an aside Ohm may have read Bequerel’s paper. In an effort to keep up with current scientific events he had taught himself to read and write French.
So Ohm gladly welcomed Poggendorff’s suggestion. As sub-text I would say that this is an example of Westernkind at its best. That is helping each other in the spirit of exploration, learning and achievement.
Ohm now set out to recreate his original experiment but this time using the thermoelectric generator instead of the voltaic pile. Ohm’s thermo-electric apparatus used copper held at or near freezing in a small basin packed with ice and snow and bismuth immersed in boiling water. Providentially these experiments were conducted in January of 1826 and there was plenty of snow and ice available allowing Ohm to begin his experiments with a large temperature, and hence tension differential. In contrast to the voltaic pile which had “a very damaging influence on the outcome and repeatability of the experiments Ohm found that the thermoelectric generators tension remained stable for thirty minutes.
Ohm tested 8 lengths of copper wire, the shortest being 2 inches , the longest being 130 inches. Then Ohm decided to do the experiment with a different temperature differential across his thermo-electric generator. In essence varying the applied voltage. This basically cemented the discovery of the proportionality between voltage, resistance and current. Ohm also demonstrated in his 1826 experiments that “cylindrical conductors of the same substance but different diameter, have the same conductivity values if their lengths are in proportion to their corss-sections”. This had far reaching implications in the understanding of current flow through conductors. For one, the finding implies that the electrical current moves through the entire cross section of the wire, not solely along the surface as static electricity was known to do.
Ohm published his results in 1826 and although he had demonstrated the proportionality of Electromotive Force, Current quantity and resistance it did not take the form of the proportionality we know today as Ohms Law. That happened in his 1827 treatise on galvanic circuits titled: The Galvanic Circuit Investigated Mathematically.
Some scientists, like, Wihlem Weber, and Carl Fredric Gauss, names any engineering student today will recognize, did understand the contribution Ohm had made. His book though was in general not well received. Although all of Ohm’s formulae and proportions had come from physical experiments as Ohm specifically states, nowhere does he detail any of it. There are no drawings or diagrams of any of his experiments. It seriously damaged the acceptance of his work at the time. Why he did this is open to historical speculation.
The criticism was so devastating that Ohm felt he had embarrassed his school. He resigned his position. From 1827 to 1833 Ohm retired to private life, moved to Berlin and earned a meager living in the way he was accustomed, tutoring mathematics. In 1833 he was able to obtain a position as a Professor in Nurnberg.
Though not well received in his own country, British inventors and scientists began to make practical use of Ohm’s work. In Charles Wheatstone’s 1841 paper describing what would later become known as the Wheatstone bridge he heaped praise upon Ohm crediting him with providing the analytic tools upon which the new electrical science would be built.
Quoting Wheatstone: The instruments and processes I am about to describe being all founded on the principles established by Ohm in his theory of the voltaic circuit, and this beautiful and comprehensive theory being not yet generally understood and admitted, even by many persons engaged in original research, I could scarcely hope to make my descriptions and explanations understood without prefacing them with a short account of the principal results which have been deduced from it. It will soon be perceived how the clear ideas of electro-motive forces and resistances, substituted for the vague notions of intensity and quantity which have been so long prevalent, enable us to give satisfactory explanations of most important phenomena, the laws of which have hitherto been involved in obscurity and doubt.
The same year the Royal Society awarded Ohm the Copley Medal for his researches into the laws of electric currents. Ohm became a foreign member of the Royal Society in 1842. Ohm’s work was so in demand in Britain that Wheatstone had his friend Ada Lovelace produce a better translation of his work. Thus foreign countries accorded Ohm the recognition his home country had denied him. In 1849 Ohm finally achieved his dream of a full University professorship. In 1852 he was made chair of physics at the University of Munich. 2 years later he died.
References:
https://todayinsci.com/O/Ohm_Georg/OhmGeorg-Bio(1930).htm
https://www.thefamouspeople.com/profiles/georg-ohm-542.php
http://n4trb.com/Publications/Ohm%20and%20the%20Mathematization%20of%20Physics.pdf
https://mathshistory.st-andrews.ac.uk/Biographies/Ohm/
https://www.youtube.com/watch?v=fk_BpXlfZ8U
Georg Simon Ohm, Nationality a German and a Westman.
Born: 16th March 1780
Died 6 July 1854
To set the historical background it is instructive to note that the French revolution took place in 1789. followed by the Napoleonic wars lasting from 1799 through 1815. In 1813 the Bavarian city of Erlangen, with a population 8,000 welcomed 33,000 billeted troops in anticipation of war or civilwar. It was a turbulent period in the history of our people.
In 1764 the Ohm family settled in the Bavarian city of Erlangen. Georg Ohm’s father as his grandfather before him was a locksmith. Georg Simon was the first of 7 children born to Johann Wolfgang Ohm and Maria Elizabeth Beck. Georg Simon’s mother died when he was 10 years old. Of the 7 children only 3 survived childhood. Georg Simon, his brother Martin and sister Elizabeth. Life was harsh.
Georg Simon’s father, Johann was a man of exceptional ability. During his travels performing locksmithing he managed to teach himself advanced mathematics, physics, chemistry and philosophy. While the children were young Johann taught them at home. Yes, the discoverer of the fundamental relationship governing electric current flow, was homeschooled.
In 1805, at 25 years of age, Ohm entered the University of Ehrlangen but got caught up in the University party scene and spent most of his time in activities other than his studies. Or did he? The historical record is not clear here as some sources say he had to leave the University after 3 semesters due to lack of funds. I believe it was for lack of funds. Ohm posesed too high degree of self discipline and personal motivation to be distracted by frivolities. At any rate he moved to Gottstadt, Switzerland where he found employment as a math tutor and continued his own private studies where he read the works of Euler, LaPlace, Fourier, Lagrange and LaCroix, to name just a few.
In April of 1811 he returned to the University of Erlangen. His private studies and high Westman IQ stood him in good stead as he received a Doctor of Philosophy Degree only 6 months later.
Take a step back and think about this. Homeschooled by his father and studying privately he acquired the knowledge to receive a doctorate degree. And he did it all the while tutoring to make a meager living.
His dream was to be a full professor but no positions were available. He joined the staff at the University as a lecturer in mathematics. But the wages were meager, poverty level. From the University of Erlangen he took a Bavarian government sponsored post teaching mathematics at school of questionable quality in Bamberg. In 1817 he was offered a position teaching mathematics and physics at the Jesuit Gymnasium in Cologne. Fortuitously, this school had a very well equipped physics laboratory. While lecturing at the school Ohm also continued to study privately as well as begin performing his own experimental investigations using the Gymnasium’s physics laboratory.
In 1820 ohm learned of Oersted’s discovery that an electric current would affect a compass needle. He immediately began to investigate this new phenomena. It is hard grasp now but at the time the relations and facts we take for granted about the simplest electric circuit were yet to be discovered and understood. At the time it was thought that possibly static electricity was of a different type or essence than the electricity of a galvanic circuit. It was believed that the current in a galvanic circuit was independent of the tension, tension is what we today would call voltage or electromotive force. This was due to an error on the part of Ampere. When Ampere placed 2 voltaic piles, that is batteries, in series he noted that the deflection of a compass needle was the same as with a single voltaic pile. His conclusion was that the current through a wire was independent of the voltage. This became the settled science of the day that Ohm had to over come. What Ampere failed to realize was that the primitive voltaic piles of the time had considerable internal resistance swamping the resistance of any short length of wire that might be connected across the pile. So when 2 piles were connected in series the resistance was doubled and the current as evidenced by a compass needle deflection stayed the same. But Ampere, nor anyone else at the time realized this.
Before Ohm the quantitative characteristics of the electric current had been described, in a vague imprecise way, by the use of terms such as intensity and quantity, to which no accurately defined meaning was attached. Ohm's genius was in introducing and defining the accurate notions of electromotive force , current strength , and resistance. He demonstrated their relationship through experiment, and stated his famous law that the electromotive force divided by the resistance is equal to the strength of the current.
Back in the Gynasium lab Ohm began his investigations using using a zinc copper voltaic pile with dilute sulfuric acid as the electrolyte. To measure current he built a Coulomb torsion balance and hung a magnitized needle from a thin torsion wire. The current carrying wire ran under the magnetized needle. The needle was first aligned with the Earth’s magnetic filed and the current carrying wire run parallel to the needle. Current was passed through 6 different lengths of wire ranging from 1ft to 75 feet and the needle deflection measured. It was assumed that the amount of needle deflection was proportional to the strength of the current. Ohm graphed the results.
But the voltaic pile was problematic, migrating gases, the changing polarization of the electrolyte, caused the pile voltage to be unstable. To account for these variations Ohm measured the open circuit voltage before and immediately after every test. Ohm published his results in 1825, they were tentative and because of the stability issues with the voltaic pile only hinted at the relationship that would later become known as Ohm’s law. Ohm’s paper was published in German, in, The Annals of Physics and Chemistry, edited by Dr. Christian Poggendorff. Poggendorff suggested in a footnote to the paper that the author try using the thermo-electric current generator invented by the Englishman Thomas Seebeck. Poggendorff thought this device more stable than the voltaic pile. The thermo-electric generator develops a small but steady current when dissimilar metals are in contact and when their opposite surfaces are exposed to a temperature differential. Today we commonly refer to this as a thermocouple.
Ohm was at an impasse, furthermore he got word of similar experiments performed by Henri Bequerel and Peter Barlow. Bequerel, Barlow and Ohm’s experiments all suffered from the instability of the voltaic pile and all obtained wildly different results. Ohm wrote, “these experiments are not free from interference by forces which in no way concern the matter in question”. As an aside Ohm may have read Bequerel’s paper. In an effort to keep up with current scientific events he had taught himself to read and write French.
So Ohm gladly welcomed Poggendorff’s suggestion. As sub-text I would say that this is an example of Westernkind at its best. That is helping each other in the spirit of exploration, learning and achievement.
Ohm now set out to recreate his original experiment but this time using the thermoelectric generator instead of the voltaic pile. Ohm’s thermo-electric apparatus used copper held at or near freezing in a small basin packed with ice and snow and bismuth immersed in boiling water. Providentially these experiments were conducted in January of 1826 and there was plenty of snow and ice available allowing Ohm to begin his experiments with a large temperature, and hence tension differential. In contrast to the voltaic pile which had “a very damaging influence on the outcome and repeatability of the experiments Ohm found that the thermoelectric generators tension remained stable for thirty minutes.
Ohm tested 8 lengths of copper wire, the shortest being 2 inches , the longest being 130 inches. Then Ohm decided to do the experiment with a different temperature differential across his thermo-electric generator. In essence varying the applied voltage. This basically cemented the discovery of the proportionality between voltage, resistance and current. Ohm also demonstrated in his 1826 experiments that “cylindrical conductors of the same substance but different diameter, have the same conductivity values if their lengths are in proportion to their corss-sections”. This had far reaching implications in the understanding of current flow through conductors. For one, the finding implies that the electrical current moves through the entire cross section of the wire, not solely along the surface as static electricity was known to do.
Ohm published his results in 1826 and although he had demonstrated the proportionality of Electromotive Force, Current quantity and resistance it did not take the form of the proportionality we know today as Ohms Law. That happened in his 1827 treatise on galvanic circuits titled: The Galvanic Circuit Investigated Mathematically.
Some scientists, like, Wihlem Weber, and Carl Fredric Gauss, names any engineering student today will recognize, did understand the contribution Ohm had made. His book though was in general not well received. Although all of Ohm’s formulae and proportions had come from physical experiments as Ohm specifically states, nowhere does he detail any of it. There are no drawings or diagrams of any of his experiments. It seriously damaged the acceptance of his work at the time. Why he did this is open to historical speculation.
The criticism was so devastating that Ohm felt he had embarrassed his school. He resigned his position. From 1827 to 1833 Ohm retired to private life, moved to Berlin and earned a meager living in the way he was accustomed, tutoring mathematics. In 1833 he was able to obtain a position as a Professor in Nurnberg.
Though not well received in his own country, British inventors and scientists began to make practical use of Ohm’s work. In Charles Wheatstone’s 1841 paper describing what would later become known as the Wheatstone bridge he heaped praise upon Ohm crediting him with providing the analytic tools upon which the new electrical science would be built.
Quoting Wheatstone: The instruments and processes I am about to describe being all founded on the principles established by Ohm in his theory of the voltaic circuit, and this beautiful and comprehensive theory being not yet generally understood and admitted, even by many persons engaged in original research, I could scarcely hope to make my descriptions and explanations understood without prefacing them with a short account of the principal results which have been deduced from it. It will soon be perceived how the clear ideas of electro-motive forces and resistances, substituted for the vague notions of intensity and quantity which have been so long prevalent, enable us to give satisfactory explanations of most important phenomena, the laws of which have hitherto been involved in obscurity and doubt.
The same year the Royal Society awarded Ohm the Copley Medal for his researches into the laws of electric currents. Ohm became a foreign member of the Royal Society in 1842. Ohm’s work was so in demand in Britain that Wheatstone had his friend Ada Lovelace produce a better translation of his work. Thus foreign countries accorded Ohm the recognition his home country had denied him. In 1849 Ohm finally achieved his dream of a full University professorship. In 1852 he was made chair of physics at the University of Munich. 2 years later he died.
References:
https://todayinsci.com/O/Ohm_Georg/OhmGeorg-Bio(1930).htm
https://www.thefamouspeople.com/profiles/georg-ohm-542.php
http://n4trb.com/Publications/Ohm%20and%20the%20Mathematization%20of%20Physics.pdf
https://mathshistory.st-andrews.ac.uk/Biographies/Ohm/
https://www.youtube.com/watch?v=fk_BpXlfZ8U