Cereal experiment – extracting metal from breakfast cereal
Your students can carry out this simple metal extraction experiment at home to prove that their breakfast cereal contains iron.
Each student will need:
- Some fortified breakfast cereal e.g. cornflakes (read the ingredients and check that it contains iron)
- A strong magnet
- Sealable zip-loc bag
- Water
- Bowl or plastic tub
- Magnifying glass (optional)
- Food liquidiser (optional)
Student instructions
What do your blood and breakfast cereal have in common with the Earth’s crust?
The answer is that they all contain iron!
We get iron from rocks called ores which are found naturally in the Earth’s crust. It is a metal for which we have many uses. We use it to build bridges, cars, hammers and cutlery.
Iron also has a really important role in your body as it is found in a molecule called haemoglobin which helps your red blood cells to carry oxygen. Our bodies can’t make iron which is why it’s important to get a supply of it from the foods we eat. Iron naturally occurs in meat, nuts and some vegetables and it is also added to other foods such as breakfast cereal.
In this experiment you will prove that breakfast cereal contains iron!
- Place about two handfuls of the breakfast cereal into the bag along with enough water to half fill it.
- Seal the bag, making sure that not too much air is inside.
- Squeeze the bag for a few minutes until the cereal has been broken down and all you have is a brown liquid. Alternatively, blend the cereal and water in a food liquidiser.
- Pour the mixture into the bowl and leave to settle for 5 minutes.
- Move the magnet around inside the mixture for a couple of minutes.
- Remove the magnet and look at it closely. Use a magnifying glass if you have one. You should be able to see tiny bits of iron on it. This iron came from the cereal.
Now try to answer these:
Why did you mash up the cereal in water first before adding the magnet?
Why does iron get added to breakfast cereal?
You might not have seen any iron on the magnet. Give a possible reason why.
In the cereal, just like in the Earth’s crust, the iron was attached to the other substances around it. Mashing the cereal with water helped to break the cereal up into tiny pieces, releasing the iron so it was easier to pick it up by the magnet.
Iron is added to breakfast cereal to make sure that people are getting enough iron in their diet. If you don’t you can develop a deficiency disease called anaemia which is a lack of red blood cells.
If you didn’t see any iron it might have been because your magnet was not strong enough to pick up the pieces of iron. Other possible reasons might be that you didn’t mix the cereal for long enough with the water, or the you didn’t leave the magnet in the mixture for long enough or that your cereal doesn’t contain much iron.
This experiment on metal extraction can also be done as a quick demonstration in school. For more demonstration ideas take a look at Free video – Reactivity of metal oxides and displacement reactions