https://spark.iop.org/ohm-overlooked Skip to main content loading Explore Menu Menu Home [ ] Search [Search] * CPD Close Take a browse CPD videos + Early career + Forces + Energy + Waves + Electricity + Matter and nuclear + Space + DOMAINS CPD Programme * Resources Close Take a browse Established resources + Practical Physics + Supporting Physics Teaching + Teaching Advanced Physics + Marvin and Milo Popular resources + Quick demonstrations and activities + Stories from Physics + Perspectives + Energy in the New Curriculum + Classroom Physics magazine + Glossary + Teaching Medical Physics + Teaching Exoplanet Physics + Teaching Football and Physics + Teaching Astronomy and Space + Teaching Radioactivity + Inside Story: Physics in Medicine + Inclusive teaching resources + Do Try This at Home + Casgliad o Adnoddau yn y Gymraeg + More... * Misconceptions * News * COVID-19 Support Search Close Travel to * Institute of Physics website * Education section of IOP website * TalkPhysics is the IOP online community forum for teachers of physics * Gender Action is an award programme which promotes and supports a whole-school approach to challenging stereotypes * SEEdash insights and tools for understanding STEM education in England * The great science teaching survey logo Electrical Resistance Electricity and Magnetism Ohm overlooked Stories from Physics for 11-14 14-16 IOP RESOURCES Georg Ohm's father was a locksmith, a background that may have given his son practical experience that was useful to his future electrical research. While pragmatically useful, Georg's relationship with his father was uneasy: when his father discovered that the young man spent his time at the University of Erlangen dancing, ice-skating and playing billiards, rather than studying, he forced his son to leave his studies. In 1806, the young Ohm was sent to Switzerland, where he worked as a private mathematics tutor, before returning to university. After graduating with a doctorate, he became a lecturer but couldn't live on the meagre salary and took up school science and mathematics teaching at a challenging school in Bamberg. Ohm's experiences in the classroom inspired him to write a geometry textbook which was praised by the King of Prussia, who offered him a role in a better school, giving the scientist more time for his research. This school had excellent practical equipment and Ohm began to investigate the contemporary received opinion that current and potential difference were independent. He carried out experiments on the deflection of a magnetised needle produced by different lengths of copper wire. He argued that his observations could be modelled through the relationship: X = ab + x where X designated the deflection of the needle, x the length of copper wire and a and b were constants. In the same year, he published another paper in which he summarised the results of his experiments in the form S=A/L where S represented the strength of current, A the sum of all the tensions and L the 'Reduzirten Lange' or the resistance. Cavendish pre-empted Ohm's statement of his eponymous law by some 70 years but his work remained unpublished and was only later rediscovered by Maxwell. Some philosophers of science categorise Ohm's law as a ceteris paribus law, rather than a true scientific law, as it is dependent on a condition (constant temperature) rather than being universally true. [IOP-storie] Ohm's work did not meet with approval at the time of publication. One critic described his research as: ...a web of naked fancies, which can never find the semblance of support from even the most superficial observation of facts: (and) he who looks on the world with the eye of reverence must turn aside from this... as the result of an incurable delusion, whose sole effort is to detract from the dignity of nature. As Ohm was a schoolteacher, word of his publication reached the minister of education who proclaimed, "A professor who preached such heresies was unworthy to teach science." This hostile reception led to Ohm resigning his teaching post. He spent many years seeking a university position, living in poverty while moving between poorly paid teaching jobs. One of the reasons Ohm's work was not more readily accepted was because he used contemporary electrical terms that had ambiguous meanings. For example, he did not clearly distinguish between force and electrical potential, and confusingly drew on ideas from Fourier's theory of heat - he refers to the 'diffusion' of electricity. The intervention of Kirchhoff, who related Ohm's concept of 'electroscopic force' with electrical potential, allowed Ohm's law to be integrated with existing electrical theory. In the final two years of his life, Ohm's fortunes reversed and he was appointed the professor of physics at the University of Munich. In addition to his electrical law, Ohm proposed an acoustic law which proposes that musical notes may be decomposed into a number of pure tones. References C. T. O'Sullivan, C. Ohm's law and the definition of resistance. Physics Education, vol. 15 no. 4, 1980, pp. 237-239, p. 238 J. F. Keithley, The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s, New York, NY, IEEE Press, 1999, p. 92 I. B. Hart, Makers of Science, London, Oxford University Press, 1923. p. 243, Available at: C. T. O'Sullivan, C. Ohm's law and the definition of resistance. Physics Education, vol. 15, no. 4, 1980, pp. 237-239, p. 238 P. L. Kapitza, Experiment, Theory, Practice: Articles and Addresses, Dordrecht, D. Reidel Publishing Company, 1980, p. 308 N. Cartwright, The truth doesn't explain much. American Philosophical Quarterly, vol. 17, no. 2, 1980, pp. 159-163, p. 162 B. Davies, A web of naked fancies? Physics Education, vol. 15, no. 1, 1980, pp. 57-61, p. 57 F. A. Fufari, Georg Simon Ohm (of Ohm's Law), IEE Industry Applications Magazine, 2003, pp. 11-13 E. Garber, The Language of Physics: The Calculus and the Development of Theoretical Physics in Europe, 1750-1914, Boston, Birkhauser, 1999, p. 156 W. Berkson, Fields of Force: The Development of a World View from Faraday to Einstein, London, Routledge, 1974, p. 131 Appears in theseCollections Thinking About Teaching Collection Stories from physics: Electricity & Magnetism Download the full booklet and explore more stories from physics. Introduction The... For 11-14 14-16 55 Resources Other resources onElectrical Resistance Ohm's Law Electricity and Magnetism PRACTICAL PHYISCS Ohm's law without a voltmeter Demonstration: an approach to Ohm's law in a quick demonstration. Practical Activity 14-16 Electrical Resistance Electricity and Magnetism PRACTICAL PHYISCS Investigating series and parallel circuits Class practical: introduces two ideas: current is shared between parallel paths in a circuit, and brightness of a lamp depends... Practical Activity 14-16 Ohm's Law Electricity and Magnetism PRACTICAL PHYISCS Ohm's law Class practical: this experiment looks at the relationship between current and potential difference (p.d.) for a length of... Practical Activity 14-16 Electrical Resistance appears in the relation V=IR P=V^2/R 1/R_tot=1/R_1+1/R_2 R_tot= R_1+R_2 R=rL/A P=I^2R G=1/R features in Ohm's Law Adding Resistors in a Circuit is used in analyses relating to Superconductor #WETEACHSCIENCE DO YOU TEACH IN THE UK OR IRELAND? Help the IOP, RSC and RSB map the secondary science teaching landscape and you might win PS100! We have 20 prizes for teachers who complete the Great Science Teaching Survey by 8 April. Responses are anonymous and only aggregate data is reported. Learn more * About IOPSpark * Supporting Physics Teaching * Teaching Advanced Physics * Practical Physics * Accessibility * Copyright * Disclaimer * Privacy * Terms & Conditions (c) 2022 IOP All rights reserved. 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