Electromagnets
An electromagnetic crane moves steel beams.Copyright 2009 Zwergelstern, Wikimedia Commons http://commons.wikimedia.org/wiki/File:Loading_Machine_Scrap_01.jpg
Students complete the grand challenge of this unit and design an electromagnet to separate steel from aluminum for a recycler. In order to do this, they compare the induced magnetic field of an electric current with the magnetic field of a permanent magnet and then make the former look like the latter. They discover that looping the current produces the desired effect and find ways to further strengthen the magnetic field.
The initial investigation into the correct shaping of the wire to achieve the desired field shape begins the engineering design process. During the activity, students proceed with the design process, making revisions to try to achieve the strongest electromagnet possible so as to pick up the most steel. Electromagnets are important inclusions to many electrical engineering designs and also supplement the work in other engineering disciplines such as mechanical and aerospace.
After this lesson, students should be able to:
- Describe how the magnetic field of an electric current can be used to create a magnetic field similar to that of a permanent magnet.
- Build an electromagnet.
- Identify the properties of an electromagnet that affect its strength.