This study investigates nineteenth century laboratory work on electromagnetism through historical accounts and experimental replications. Oersted found that when a magnetic needle was placed in varying positions around a conducting wire, its orientation changed: in moving from a spot above the wire to one below, its sense inverted. This behavior was confusing and provocative. Early experimenters such as Johann Schweigger, Johann Poggendorff, and James Cumming engaged it by bending wire into loops. These loops, which increased the magnetic effect on a compass placed within, also provided evidence of their understanding and confusion. Coiling conducting wires around iron magnetized it, but when some wires coiled oppositely from others, the effect diminished. This effect confused contemporaries of Joseph Henry who made electromagnets, and amateurs later in the century who constructed multisection induction coils. I experienced these confusions myself while working with multilayer coils and induction coils that I made to replicate the historical instruments. This study shows how confusion can be a productive element in learning, by engaging learners to ask questions and invent experiments. By providing space for learners’ confusions, teachers can support the development of their students’ physical understandings.

1.
Christopher
Jones
, “
Faraday’s law apparatus for the freshman laboratory
,”
Am. J. Phys.
55
(
12
),
1148
1150
(
1987
);
Kenneth D.
Skeldon
,
Alistair I.
Grant
, and
Sean A.
Scott
, “
A high potential Tesla coil impulse generator for lecture demonstrations and science exhibitions
,”
Am. J. Phys.
65
(
8
),
744
754
(
1997
);
O. L.
de Lange
and
J.
Pierrus
, “
Measurement of bulk moduli and ratio of specific heats of gases using Rüchardt’s experiment
,”
Am. J. Phys.
68
(
3
),
265
270
(
2000
);
R. V.
Krotkov
,
M. T.
Tuominen
, and
M. L.
Breuer
, “
Franklin’s Bells’ and charge transport as an undergraduate lab
,”
Am. J. Phys.
69
(
1
),
50
55
(
2001
).
2.
Heinz Otto
Sibum
, “
Reworking the mechanical value of heat: Instruments of precisions and gestures of accuracy in early Victorian England
,”
Stud. Hist. Philos. Sci.
26
(
1
),
73
106
(
1995
);
“The Language of instruments: A study on the practice and representation of experimentation” in Experimental Essays, edited by M. Heidelberger and F. Steinle (Nomos, Baden-Baden, Germany, 1998).
For an overview of the measurements of Joule’s constant, see
Thomas
Greenslade
, “
Nineteenth-century measurements of the mechanical equivalent of heat
,”
Phys. Teach.
40
,
243
248
(
2002
).
3.
Peter
Heering
, “
On Coulomb’s inverse square law
,
Am. J. Phys.
60
,
988
994
(
1992
);
“The replication of the torsion balance experiment: The inverse square law and its refutation by early 19th-century German physicists,” in Restaging Coulomb: Usages, Controverses et Replications autour de la Balance de Torsion, edited by C. Blondel and M. Dörries (Leo S. Olschki, Firenze, 1994).
4.
Klaus Staubermann, “Controlling vision—The photometry of Karl Friedrich Zöllner,” Dissertation, Darwin College, Cambridge University, 1998.
5.
For replication studies of Galileo’s experiments, see
Thomas
Settle
’s article, “
An experiment in the history of science
,”
Science
133
,
19
23
(
1961
) and his longer essay Galileo’s Experimental Researches, Berlin (Max-Planck-Institut fur Wissenschaftsgeschichte, Berlin, 1996);
Elizabeth
Cavicchi
, “
Painting the Moon
,”
Sky Telesc.
82
(
3
),
313
314
(September
1991
).
6.
David Gooding, Experiment and the Making of Meaning (Kluwer, Dordrecht, 1990);
Dietmar
Höttecke
, “
How and what can we learn from replicating historical experiments
,”
Sci. and Educ.
9
(
4
),
343
362
(
2000
).
7.
Elizabeth Cavicchi, “Experimenting with wires, batteries, bulbs and the induction coil: Narratives of teaching and learning physics in the electrical investigations of Laura, David, Jamie, Myself and the nineteenth century experimenters—Our developments and instruments,” Dissertation, Harvard Graduate School of Education, 1999.
8.
For the replication of Faraday’s capacitance work, see Chap. 2 of Dietmar Höttecke, “Die Nature der Naturwissenschaften hisorisch verstehen. Fachdidaktische und wissenschaftshistorische Untersuchungen,” Dissertation, University of Oldenburg, Germany, 2001.
9.
Elizabeth
Cavicchi
, “
Experimenting with magnetism: Ways of learning of Joann and Faraday
,”
Am. J. Phys.
65
(
9
),
867
882
(
1997
).
10.
Ryan D. Tweney, “Epistemic artifacts: Michael Faraday’s search for the optical effects of gold,” in Model-Based Reasoning: Science, Technology, Values, edited by L. Magnani and N. J. Nersessian (Kluwer Academic/Plenum, New York, 2002).
11.
Samuel
Devons
and
Lillian
Hartmann
, “
A history-of-physics laboratory
,”
Phys. Today
22
(
2
),
44
49
(
1970
);
Lillian
Hartmann Hoddeson
, “
Pilot experience of teaching a history of physics laboratory
,
Am. J. Phys.
39
,
924
928
(
1971
);
John
Bradley
, “
Repeating the electromagnetic experiments of Michael Faraday
,”
Phys. Educ.
26
,
284
288
(
1991
);
Elspeth
Crawford
, “
A critique of curriculum reform: Using history to develop thinking
,”
Phys. Educ.
28
,
204
208
(
1993
);
Michael
Barth
, “
Electromagnetic induction rediscovered using original texts
,”
Sci. and Educ.
9
(
4
),
375
387
(
2000
);
Peter
Heering
, “
Getting shocks: Teaching secondary school physics through history
,”
Sci. and Educ.
9
(
4
),
363
373
(
2000
).
12.
P. Heering, Ref. 11.
13.
American Association of Physics Teachers
, “
Goals of the Introductory Physics Laboratory
,”
Am. J. Phys.
66
(
6
),
483
485
(
1998
).
14.
As an assist in deciding the magnetization sense associated with a current-bearing wire, Ampère pictured an observer swimming inside the wire: feet in the direction from which current comes; head in the direction it goes. As the observer sees it, a magnetized needle always turns toward the observer’s left. André Marie Ampère, Exposé des Nouvelles découvertes sur L’électricité et le Magnétisme (Méquignon-Marvis Libraire, Paris, 1822). For a discussion of other early statements of the rule,
see
Thomas
Greenslade
, “
Ancestors of the right-hand rule
,”
Phys. Teach.
18
,
669
670
(
1980
).
15.
Elizabeth Cavicchi, unpublished lab notebook entry of April 8, 1997.
16.
“The Needle,” Chap. 73, Herman Melville, Moby Dick or The White Whale (Harpers, New York, 1851).
17.
For background on Oersted’s work and thinking, see Anja Skaar Jacobsen, “Between Naturphiosophie and Tradition: Hans Christian O/rsted’s Dynamical Chemistry,” Dissertation, University of Aarhus, Denmark, 2000.
18.
Quote on pp. 322–3 in
John Christian
Oerstead
, “On electro-magnetism,” Ann. Phil. 2, 321–337 (November 1821).
19.
John Christian
Oerested
, “Experiments on the effect of a current of electricity on the magnetic needle,” Ann. Phil. 16, 273–276 (July–December 1820), see p. 276.
20.
The use of “the botanic term dextrorsum (defining the helicity of climbing plants)” in Oersted’s Latin text constitutes the first “mnemonic device” for the relation between magnetism and current direction; see Oliver Darrigol, Electrodynamics from Ampère to Einstein (Oxford U.P., Oxford, 2000), p. 5.
21.
First privately printed on July 21, 1820 and circulated among friends, Oersted’s brief Latin tract was immediately translated and reprinted in all the leading European science journals. See Bern Dibner, Oersted and the Discovery of Electromagnetism (Blaisdell, New York, 1962).
22.
Jean
Baptiste Biot
and
Félix
Savart
, “
Note sur le magnétisme de la pile de Volta
,”
Annales de Chimie et de Physique
xv
,
222
223
(
1820
) and Précis Élémentaire de Physique Expérimentale (Déterville, Paris, 1824), 3rd ed., translated excerpts from these papers are provided in
R. A. R. Tricker, Early Electrodynamics: The First Law of Circulation (Pergamon, Oxford, 1965), pp. 118–119, 119–139.
23.
André Marie
Ampère
, “
Sur l’action des Courents voltaiques
,”
Ann. Chim. (Paris)
xv
,
59
76
(
1820
). Translated excerpts in
R. A. R. Tricker, Ref. 22, pp. 140–154. For a recent analysis of the historical development of electrodynamics, see O. Darrigol, Ref. 20.
24.
Quote on p. 199 of Michael Faraday’s anonymously published “Historical sketch of electro-magnetism,” Ann. of Phil. (London) 18, 195–200 (1821). For a further discussion of confusions and experimental responses to Oersted’s work,
see also Chap. 2 of D. Gooding, Ref. 6.
25.
Schweigger was a chemistry and physics instructor at the University of Halle (Germany) and founding editor of Journal für Chemie und Physik;
see
H. A. M.
Snelders
, “
J. S. C. Schweigger: His romanticism and his crystal electrical theory of matter
,”
Isis
62
,
328
338
(
1971
).
26.
I. S. C.
Schweigger
, “Zusätze au Oersteds elektromagnetischen Versuchen,” J. Chemie Physik 31, 1–17 (1821).
Translated excerpt on p. 129 of
Robert A.
Chipman
, “The earliest electromagnetic instruments,” U.S. Natl. Mus. Bull. 240, 122–136 (1966).
27.
Translated quote on p. 130 of R. A. Chipman; original in Schweigger, Ref. 26.
28.
Earlier, glass was used to insulate the sides of current carrying wires that were immersed in electrolyte solutions; see
John George
Children
, “
An account of some experiments, performed with a view to ascertain the most advantageous method of constructing a voltaic apparatus, for the purposes of chemical research
,”
Philos. Trans. R. Soc. London
99
,
32
38
(
1809
).
29.
Translation by Petra Lucht on December 16, 1997; original quote on p. 35 of
I. S. C.
Schweigger
, “Noch einige Worte über diese neueu elektromagnetischen Phänomene,” J. Chemie Physik 31, 35–41 (1821).
30.
N and n designate north magnetic polarity; S and s designate south.
31.
Translation by Petra Lucht on December 16, 1997; original quote on p. 38 of Schweigger, Ref. 29.
32.
Ampère observed that when coils were wound in the opposite handed sense, their magnetic polarities were opposite. Using his theory that all magnetism was due to circulating current loops, he worked out a rule relating the direction of current circulation to the polarity of the magnetism it produces (Ref. 14). See “Expériences relatives á l’aimantation du fer et de l’acier par l’action du courant voltaı̈que,” Ann. Chim. Phys. 15, 93 102 (1821) (no author given but probably the editor, Gay-Lussac); and
L. Pearce
Williams
, “
What were Ampère’s earliest discoveries in electrodynamics?
,”
Isis
74
,
492
508
(
1983
).
33.
For a discussion of the exploratory nature of Ampère’s early electromagnetic experimenting, see Friedrich Steinle, “Exploratory versus theory-dominated experimentation: Ampère’s early research in electromagnetism,” in Experimental Essays, Ref. 2.
34.
For a historical survey of electrical measurement instruments, see Joseph Keithley, The Story of Electrical and Magnetic Measurements: From 500 B.C. to the 1940s (IEEE Press, New York, 1999).
35.
Johann Christian Poggendorff was trained in pharmacy, but being too poor to own a store, he commenced university studies in science in 1820. Later he was a physics professor at the University of Berlin and editor of Annalen der Physik and of a bibliographic reference comprehensive of all scientific publications; see Dictionary of Scientific Biography, edited by C. Gillispie (Charles Scribners’ Sons, New York, 1970–1980).
36.
Poggendorff’s professor,
Paul
Erman
, first reported on his “magnetic condensor” in “Ein electrisch-magnetischer Condensator,”
Ann. Phys. (Leipzig)
67
,
422
426
(
1821
);
sections are excerpted and translated in Wilhelm Ostwald, Electrochemistry: History and Theory (Smithsonian Institute, Washington, DC, 1980).
Poggendorff’s own subsequent publication is in Gothic font,
J. C.
Poggendorff
, “
Physisch-chemisch Untersuchungen zur näheren Kenntniss des Magnetismus der voltaischen Säule
,”
Isis von Oken
8
,
687
710
(
1821
), and partially translated by R. A. Chipman in Ref. 26.
37.
Using a coil’s needle as a detector, Poggendorff first showed that graphite and other nonmetals would carry a voltaic current. He termed them “semi-conductors” (“halb-Leiter”); Ref. 26, p. 133.
38.
Parallel wiring’s enhanced electromagnetism was exploited by Henry’s electromagnet (see Ref. 46). However, because it is an outcome of the relative balance between the internal resistance of the voltaic unit and the external resistance of coil and circuit, it was not observed when other voltaic combinations were used; see Cavicchi in Ref. 7.
39.
D. B.
[David Brewster], “Account of the new galvano-magnetic condenser invented by M. Poggendorf of Berlin,” Edin. Phil. J. 5, 112–113 (1821), see fig on p. 821.
40.
Faraday in Ref. 24, pp. 289–290.
41.
Quote on p. 289 of
James
Cumming
, “Description of the galvanoscope,” Ann. Phil. 6, 288–289 (1823).
42.
Quote on p. 289 of Ref. 41.
43.
Quote on p. 273 of
James
Cumming
, “
On the connexion of galvanism and magnetism
,”
Trans. Cambridge Philos. Soc.
1/2
,
269
279
(
1821
);
James
Cumming
, “
On the application of magnetism as a measure of electricity
,”
Trans. Cambridge Philos. Soc.
,
1/2
,
281
286
(
1821
).
44.
Reference 43, p. 275.
45.
Joseph
Ames
, “
Certain aspects of Henry’s experiments on electromagnetic induction
,”
Science
75
,
87
92
(
1932
).
46.
Joseph
Henry
, “
On the application of the principle of the galvanic multiplier to electro-magnetic apparatus, and also to the developement [sic.] of great magnetic power in soft iron, with a small galvanic element
,”
Am. J. Sci.
19
,
400
408
(
1831
).
Also in Joseph Henry, The Scientific Writings of Joseph Henry (Smithsonian Institution, Washington, DC, 1886), Vol. 1.
47.
Reference 46, Am. J. Sci., p. 404.
48.
Henry attributed to Schweigger the precedent in this finding that a conducting wire’s magnetism was greater when it was composed of several separate wire coils in parallel, than of one long series length. However, it appears that Poggendorff, not Schweigger, made those prior observations. This was not a general result (as Henry supposed) but dependent on the specific balance between internal and external resistance in the circuit. If the battery’s internal resistance is lower than that of an individual wire coil, the magnetic effect will be greater when several wire coils are connected in parallel, than when they are in series. For my investigations of these properties in Henry’s electromagnet and mine, see Cavicchi, Ref. 7.
49.
Letter of May 8, 1832, in Joseph Henry, The Papers of Joseph Henry, edited by Nathan Reingold (Smithsonian Institution Press, Washington, DC, 1972), Vol. 1, December 1797–October 1832.
50.
Letter of April 23, 1832 in Ref. 49.
51.
James Chilton to Henry, Letter of December 29, 1834, in Joseph Henry, The Papers of Joseph Henry, edited by Nathan Reingold (Smithsonian Institution Press, Washington, DC, 1975), Vol. 2, November 1832–December 1835.
52.
Quote on p. 145 of
Robert
Hare
, letter to editor,
Am. J. Sci.
20
,
144
147
(
1831
).
53.
Quote on p. 23 of Ref. 15.
54.
Quote on p. 492 in
Nicholas
Callan’s
paper, “On a method of connecting electro-magnets so as to combine their electric powers and on the application of electro-magnetism to the working of machines,” Annals of Electricity, Magnetism and Chem. 1, 491–494 (1837). I have replicated Callan’s experiment to combine the primaries and secondaries of two similar hand-wound induction coils. Using an oscilloscope as a detector of the induced voltages, I observed that when the coils’ winding sense is opposing, the induced voltage is substantially diminished, like the effect Callan mentioned in this quote.
55.
Advice to keep the winding sense of the secondary consistent with that of the primary is given in such manuals as John Sprague, Electricity: Its Theory, Sources, and Applications (Spon, London, 1875);
F. C. Allsop, Induction Coils and Coil-Making (Spon, London, 1894);
Charles Seaver, American Boy’s Book of Electricity (McKay, Philadelphia, PA, 1921).
56.
For advice on keeping the current sense consistent between sections, see H. S. Norrie, Ruhmkorff Induction-Coils (Spon, London, 1896), p. 14;
James
Hobart
, “Construction of a jump spark ignition coil and condenser,” Am. Electrician 14 (12), 576–577 (1902).
57.
A. Frederick Collins, The Design and Construction of Induction Coils (Munn, New York, 1909), pp. 75–77.
58.
The secondary of my induction coil is about 1 km long, having a total resistance of 1.1 kΩ; with a single D cell input to its primary, its secondary induced signals of 6–8 kV. For a fuller account of my induction coil replication and its operation, see Chap. 20 of Ref. 7.
59.
For research and analysis of learners’ physical intuitions as resources for learning physics, see
John P.
Smith
III
,
Andrea A.
diSessa
, and
Jeremy
Roschelle
, “Misconceptions reconceived: A constructivist analysis of knowledge in transition,” J. Learn. Sci. 3 (2), 115–163 (1993);
David
Hammer
, “Student resources for learning introductory physics,” Am J. Phys., Phys. Ed. Res. Suppl. 68 (S1), S52–S59 (2000);
Andrea diSessa, Changing Minds: Computers, Learning, and Literacy (MIT, Cambridge, MA, 2000).
60.
See the discussion of historical explorations in
Neil
Ribe
and
Friedrich
Steinle
, “
Exploratory experimentation: Goethe, Land, and color theory
,”
Phys. Today
55
(
7
),
43
49
(
2002
).
61.
For examples of learners’ and teachers’ developments through taking their confusions seriously, see Eleanor Duckworth, “Learning with breadth and depth,” in The Having of Wonderful Ideas and Other Essays on Teaching and Learning (Teachers’ College Press, NY, 1996);
and the essays in Tell Me More: Listening to Learners Explain, edited by E. Duckworth (Teachers’ College Press, New York, 2001).
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