Just as you can use a magnet to pick up a nail, you can use a magnet to pick up the small pieces of iron in your cereal. Iron is usually not a magnet (you can't pick up one nail with another), but it becomes magnetized when you put it close to a magnet. This is why you can pick up a nail with a magnet.
Have you ever brought two magnets close to one another and felt them attract each other? Magnets apply forces - pushes or pulls - to other magnets that can make them move. When you stir the magnet through the mixture, the force from the magnet on the iron shavings is so strong that the iron shavings stick to the magnet!
Try This!
•Put the mixture in a clear, plastic cup. Hold the magnet on the outside of the cup and stir the mixture with a plastic spoon. Can you see a dark spot (made by the iron shavings) forming on the inside of the container behind the magnet? Try dragging the magnet and see if you can get the dark spot to follow. What happens when you take the magnet away from the cup?
•Repeat the experiment with two or more kinds of cereal. Is there a big difference between them? Check the side of the box and compare the percentage of "recommended daily allowance" (RDA) of iron that is in each cereal.
•The RDA of iron is about 14 milligrams. The average 2-inch nail weighs about 2.51 grams (2,510 milligrams). If you got your RDA of iron each day by eating iron fortified cereal, how many nails worth of iron would you eat in one year?