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Experimental Suitability Analysis of the Iron Core Materials Used in Elementary School Electromagnet Experiments
New Phys.: Sae Mulli 2018; 68: 196~201
Published online February 28, 2018;
© 2018 New Physics: Sae Mulli.

Beomgil CHOI, Youngseok JHUN*

Department of Science Education, Seoul National University of Education, Seoul 06639, Korea
Correspondence to:
Received October 30, 2017; Revised December 4, 2017; Accepted December 14, 2017.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Threaded bolts have been replaced by iron nails in electromagnet experiment activities in the textbook for the 2009 revision of the elementary science curriculum because of the slight residual magnetism. However, the related research is rare, so we tried to determine the optimized heating condition of the iron nail so that the residual magnetism would be a minimum. Then, the optimized nail was compared to the threaded bolt to determine which one would be better for use in the core of an electromagnet. We found an optimized heating condition of nail for use in the core of an electromagnet. In addition, we found that a nail that had been subjected to the optimal heating treatment was better than a threaded bolt as the difference between the residual magnetic field strength in the nail and that in the threaded bolt was not very much while the magnetic field strength induced in the nail by an electric current was more than three times larger.
PACS numbers:, 01.50.Pa, 07.55.Db
Keywords: Eletromagnet, Iron core, Heating condition, Residual magnetic field

February 2018, 68 (2)
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