Theory

Manufacturers add iron to some cereals - and other food products such as flour - as a finely divided powder. This will dissolve in the stomach acid before being absorbed by the body.

It is added in this form (before cooking) because it does not produce any taste or interact chemically with the other components of the product.

'Special K' packets quote about 20mg of iron per 100g of cereal. Products such as cornflakes which are fortified at a lower level have about 6.7 mg of iron per 100g while unfortified breakfast cereals have 1-2 mg of iron per 100g.

Extensions

Repeat the demonstration with other cereals or other foods.


Safety

Wear eye protection.

The slurry resulting from the demonstration can be safely poured down the sink. It is probably worth re-stating the rules about not eating in laboratories.