How attractive is your cereal?
Image: Kagen McLeod
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Key concepts
Elements
Metals
Magnetism
From National Science Education Standards: Properties of Earth materials
Introduction
What does your breakfast cereal have in common with Earth's crust? They both have some of the same materials in them. It might seem strange to compare a bowl of cornflakes to a pile of dirt. But science can help us find one of the most common elements on Earth in your cereal: iron.
Even though iron only makes up less than 5 percent of the mass on Earth, it is found in a lot of places: rocks, cereal—and even in your blood! It's also the most frequently used metal on the planet; it makes up most of steel, which is a mixture of iron and other ingredients.
Background
If you have ever seen rocks or dirt that have a red or orange tint to them, they most likely contain iron; iron tends to rust when it is exposed to oxygen, causing that rusty red color on old metal objects—or rocks! Iron also plays an important role in our bodies. It is found in a part of our blood called hemoglobin, which helps our blood to carry oxygen molecules from our lungs to the rest of our bodies.
Our bodies can't produce iron, but it's naturally present in many foods, including meats (beef, pork, turkey), produce (raisins, spinach, prunes) and nuts (walnuts, cashews, peanuts). And it's so important for our bodies to have enough iron that some food makers put a dash of it in other food products—such as fortified breakfast cereal. (Of course it wouldn't be healthy to eat iron on its own, so stick to getting your daily dose via food and vitamins.)
Like many metals, iron is magnetic, so if you have a strong enough magnet, you will be able to pick it up. Will you be able to pick up your box of breakfast cereal just by magnetic force alone? No, because it doesn't contain enough iron for the magnetism to overpower gravity pulling the weight of all that cereal down. But we are going to find a way to remove—or "extract"—the iron from that cereal and pick it up with a magnet.
Materials
• Breakfast cereal that contains iron, such as fortified cornflakes (check the label to see how much iron each serving contains—the more the better!)
• Bowl and spoon (or mortar and pestle)
• Magnet (as strong as possible)
• White piece of paper
• Resealable zip-top bag (optional)
• Water (optional)
Preparation
• Pour out one serving of iron-fortified dry cereal into the bowl (or the mortar if you have one).
• Try passing the magnet over the flakes. Are they pulled up by the magnet? Why not?
Procedure
• Crush the cereal with the back of a spoon, pestle or other firm kitchen utensil. Keep crushing it until it becomes a fine powder (the finer you can get it, the easier it will be to separate out the iron particles).
• Carefully pour the powder onto the white piece of paper in a thin layer.
• Run the magnet closely over the top of the cereal powder. Is the magnet picking up any black particles? Those are bits of iron! (If you aren't collecting any, make sure your powder is fine enough and try running the magnet through it—otherwise, you might need a stronger magnet.)
• How much iron did you get out of the cereal?
• If you want to try to get more iron, carefully pour the cereal into the resealable plastic bag.
• Fill the bag halfway full of water (warm water works well).
• Carefully seal the bag and gently swish the liquid around until the cereal powder has dissolved.
• Gently insert the magnet into the bag (if your magnet has a handle, carefully move it around without spilling the liquid; if your magnet does not have a handle, you can drop it in the bag and reseal it).
• Examine the magnet's surface—were you able to collect more iron?
• Extra: try this activity with different types of cereals and see whether you collect more or less iron. Compare your findings with the nutrition facts labels on the boxes.
Read on for observations, results and more resources.
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10 Comments
Add CommentFor a long time I've wondered why many forms of degraded organic matter tend to be brown or toward the red end of the visible spectrum, rather than toward the blue end. There are many examples, cereal, dead grass, wood, rotten apples ... I'm sure you can think of some others, though some are clearly due to specific chemicals such as tannic acid and bile, or so I'm told. What organic matter can you think of that's bluish (except flowers), perhaps as it degrades?
Reply | Report Abuse | Link to thisNow I'm wondering if organic browns generally represent various forms of oxidized iron, as with rust.
Please copy response to danrob@efn.org
Humans don't metabolize metallic iron, only ionic iron. Ionic iron isn't attracted by a magnet. If a breakfast cereal has metallic iron, it maybe comes from a contamination source, not from a fortification compound.
Reply | Report Abuse | Link to thisThe brown or red color in organic matter comes from many sources, such like oxidation of polyphenols; or from Maillar reaction between proteins and sugars; or from the presence of carotenoids.
Reply | Report Abuse | Link to thisAnother excellent article...haven't tried it myself yet...thanks for the simple explanation...
Reply | Report Abuse | Link to thisIvan...I think the acid in the stomach would breakdown small enough particles...anyone else have some input to this....
A funny and informative experiment, but don't forget Iron in food improves your health ( Under most circumstances )
Reply | Report Abuse | Link to thisWe could not find any iron in our cereal Mesa Sunrise.We went outside and used our magnets in the dirt to check if they worked instead and found lots of iron! We had fun. From gracie and dashiell
Reply | Report Abuse | Link to thisI tried this with my kids, with store brand oat cereal. We didn't see any black particles at all. There were some particles that stuck to the magnet (we used the super strong little magnets) but they looked like crushed up cereal dust in terms of color. It would have been really cool to actually see some dark colored iron sticking to the magnets, but no such luck.
Reply | Report Abuse | Link to thisMetallic iron powder is added to foods to fortify them. As Ivan notes, humans do not metabolize metallic iron, however iron powder is (fairly) efficiently dissolved by stomach acid creating the ions that the body can use. If you want to extract iron powder from your food read the label before you buy it and buy something that is fortified with iron. Do yourself a favor and buy flour so you can skip the grinding step. :)
Reply | Report Abuse | Link to thisMetallic iron powder is added to various foods as a supplement. In the finely divided state oxygen or other oxidizing agents convert it to a metabolizable form.
Reply | Report Abuse | Link to thisAzulenes are blue.
Reply | Report Abuse | Link to this