Chemical Education Today
Report
Iron in Breakfast Cereal Demonstrations for National Chemistry Week 2004 by Erica K. Jacobsen and James Maynard Iron plays an important role in maintaining health in the human body. Hemoglobin, a protein in the blood that transports oxygen, constitutes 60–70% of the human body’s iron. Iron is present in hemoglobin in the form of Fe2+ ions. These ions form a loose covalent bond with oxygen as the hemoglobin picks up oxygen in the lungs; once the hemoglobin reaches tissues in need of oxygen, the bond breaks. We have many options for how to obtain iron nutritionally. Some products, such as breakfast cereals, are labeled
“iron-fortified”. Several cereals offer “100% of the daily value” of multiple vitamins and minerals, including iron. A JCE Classroom Activity investigating the iron in breakfast cereals is in this issue of the Journal (pages 1584A–1584B). Erica K. Jacobsen is Associate Editor, Secondary School Chemistry, JCE;
[email protected]; James Maynard is Lecture Demonstrator in the Department of Chemistry, University of Wisconsin–Madison, Madison, WI 53706.
Background
Demo 1
photo by J. J. Jacobsen, E. K. Jacobsen, J. Cunningham
Cereal manufacturers have a few choices for how they include iron in their products. Some cereal manufacturers prefer to add particles of pure iron metal (called elemental iron or reduced iron) because elemental iron is stable in storage and does not affect the cereal’s flavor. General Mills’ brand-name “Total” is one such cereal. The addition of this strongly magnetic form of iron allows the “Total” cereal to be used in two interesting demonstrations described here. In the first demonstration, a flake of “Total” cereal is inserted between the two poles of a permanent magnet. The iron in the cereal allows the flake to remain suspended between the two poles. Patience is required to duplicate this demonstration. Not all flakes contain the same quantity of iron, so it may take some trial and error to find a flake that is attracted to the magnet strongly enough to support the weight of the flake. The flake should be held between the two poles and then gently released.
Demo 2
First, the cereal is finely crushed using a mortar and pestle.
The second demonstration again uses “Total” cereal along with a small, cylindrical neodymium magnet. These magnets can be purchased from science supply companies.
1544
Except as noted, all photos by J. J. Jacobsen and J. Maynard
The resulting crushed pieces are scattered over a piece of clear Plexiglas (or a piece of white posterboard). The neodymium magnet can then be moved around underneath the Plexiglas or posterboard. This drags the iron filings through the crushed cereal. The iron filings are visible to the naked eye as they are attracted to the magnet underneath. It is possible to create patterns in the crushed cereal by dragging the iron filings in this way.
Journal of Chemical Education
•
Vol. 81 No. 11 November 2004
•
www.JCE.DivCHED.org
