This practical can be used as a fun filler lesson as well as in chemistry lessons where the extraction technique may be useful. Also some biology lessons which teach why eating iron rich foods are good for you may find this useful.
Cereals which are ‘fortified with iron’ actually contain food-grade pieces of iron. Although very small, these pieces will stick to a powerful magnet and can be seen if the cereal is finely crushed and the iron separated.
Equipment required (per set):
- Fortified cereal (eg. bran flakes)
- Large beaker
- Strong (neodymium) magnet
- Pestle and mortar
- Sheet of white paper
Neodymium magnets are incredibly powerful. Fairly cheap examples can be purchased through lab suppliers and some toy shops. They are also one of the components in some computer hard drives.
Students can float whole pieces of the cereal on water in the large beaker and try to attract them using the magnet.
The cereal can then be powdered and placed on top of a white sheet of paper with the magnet below. By moving the magnet (or the paper) you should be able to see some of the tiny iron pieces move towards the magnet.