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How strong are your breakfast cereal flakes?

  • How do you think cereal type and flake width affects break point?

  • The experiment finds the break point of cereal flakes

  • NPL runs, designs and checks similar tests
    on materials for engineers to make the world safer

Estimated time: 30 minutes     
No experience needed

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Equipment required

  • Flat surface kitchen weighing scales
  • Two similar pencils/pens
  • Blu-tack
  • Cereal flakes
  • Ruler
  • Pencil and paper to record results


Make sure the measurement area is clean and tidy before and afterwards.

Step by step

Watch the video, then follow the instructions.

  1. Build your test apparatus. Arrange two pencils on your kitchen scales with a small gap between, and secure with Blue-tac

  2. Pick up your first flake for investigation

  3. Measure and write down the ‘width’ of the flake (not thickness). Also record type (cornflake, bran flake, etc)

  4. Place the flake sample on the test apparatus so the larger length bridges the pencils

  5. Tare the scales (set them to zero)

  6. Push your finger down on the flake between the pencils very slowly increasing pressure while looking at the scale’s reading. Write down the reading when the flake breaks

  7. Convert your reading of the weight in kg to force by multiplying by 10. Your answer will now be in newtons (N)

  8. Repeat for as many as you can, then copy your results into the table below


Thoughts, tips and information

SI measurement units

  • metre (m) for length
  • newton (N) for force (= kg m / s2)

Challenge Topics: Measurement Science, Maths, Physics, Materials Testing

  • Will wider flakes break with more force than narrow ones?
  • Will breaking different types of flake need different forces?
  • Does break force relate to crispiness and are cereals better when crispy?
  • NPL has performed similar testing on biscuits and measured the sound of the snap to indicate crispness.
  • Electronic weighing scales convert a force measurement to mass units (kg, g etc). By multiplying the kg reading by 10, we obtain the force value measured in newtons (written N).

Discover the results of break a flake

To find out the results of our first #measurementathome challenge, read our report.

Break a Flake Report