compounds Elements mixtures
Age Group
12 13 14 15
Expected time
2 periods
Eating nails.PDF
beaker symbol

Eating nails

What’s the mystery? Are we really eating nails? How can there be iron in our cereal? The mystery here is the teacher demonstrating that iron filings can be extracted from a sample of breakfast cereal.
Domain(s) Chemistry.
Subdomain keywords Elements, compounds, mixtures.
Age group 12 to 15 years old.
Expected time for the mystery Approximate time for teacher preparation: 15 min.Approximate time in classroom: 80 min.
Safety/supervision Food used in any lab experiment is not to be eaten.Care should be taken when using food blender: ensure the blender is switched off at the wall until it is properly set up and ensure the lid is on before blending.Care is to be taken when handling hot glassware: use tongs or heat-resistant gloves.Disclaimer: the authors of this teaching material will not be held responsible for any injury or damage to persons or properties that might occur in its use.
Preparation and list of materials For a teacher-engaged demonstration:

  • Blender
  • Breakfast cereal containing added iron
  • Strong magnet
  • Projector (if available)

For a student-explore activity:

  • Beaker
  • Strong magnet
  • Mass balance
  • Weigh boats
  • Spatula
  • Test tube
  • Tongs
  • Bunsen burner
  • Pestle and mortar
  • Iron filings
  • Sulphur
  • 1.0M HCl


Some materials can be found at home (food blender).

Neodymium magnets are more effective if they are available. These can be sourced from science education equipment suppliers. Care is required when handling these powerful magnets.

Learning objectives
  • Students will learn about the properties of elements (e.g. iron).
  • Students will understand the difference between a mixture and compound.
  • Students will test and observe the properties of a mixture and a compound.
Resources There are a number of YouTube videos showing how to extract iron from breakfast cereal:

There are also many videos on You Tube about the various ways in which teachers can introduce the concepts of elements, compounds, and mixtures to students:

An additional short documentary-style video can be viewed on how blood doping works: