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Bicycle helmet.

Design for Safety activity C4. Using models in science is introduced through exploring the design of bicycle helmets.

Activity C4: Helmets [ZIP, 406 KB]

How to use this activity

It’s important to understand how a helmet works to protect your brain. However, be watchful for anyone who has close personal knowledge of a head injury and be sensitive to their needs.

The focus of this session is on developing the students’ ability to recognise and use models in science to represent something difficult to see or investigate in real life.

Two models are used – one as a teacher demonstration and one as a student activity. The teacher demonstration uses eggs as a model of the human head, with a hard protective outer and fragile soft inner. Skull = eggshell, brain = white and yolk. Try this out before doing it with the class.

It is important that students think about how the model is presented and ask questions such as:

  • What does this tell us?
  • Is it totally correct? Is anything left out or not quite right?
  • How does this representation get the message across?
  • Why is it useful to represent the head using an egg?

The teaching of models as representations is covered well here:

Teaching with models (Science Online | TKI)(external link)

How to fit a bicycle helmet:

Cycle helmets | The official New Zealand code for cyclists(external link)

Where it fits in the New Zealand Curriculum

Nature of Science strand

Investigating in Science – exploring, predicting, defining, analysing.

  • Science activities can be used to develop any of the Nature of Science sub strands.
  • Identify aspects of Investigating in Science that your students need to get better at or understand more fully.
  • Then frame your unit to be very clear about these things when you do them.

NZ Curriculum | Science achievement objectives(external link)

Capability focus

Interpret representations.

The five science capabilities (TKI - Science online)(external link)

Contextual strand

Living World, Achievement Objective: Life Processes; recognise that there are life processes common to all living things.

Physical World, Achievement Objective: explore, describe and represent patterns and trends for everyday examples of physical phenomena, such as movement, forces etc.

Big science idea

Cycle helmets protect the head by reducing the rate at which the skull and brain are accelerated or decelerated by an impact.


  • Your brain is very fragile and is protected by your skull.
  • The helmet liner in a cycle helmet acts like a shock absorber.
  • The helmet liner absorbs the energy of the fall, reducing the force of impact to the head.

Capability concepts

  • A model is a representation of an idea, an object, a process or a system.
  • Models are often used when the thing scientists want to talk or think about is not directly observable.
  • Models are rarely perfect and are likely to have strengths and weaknesses.

Possible learning objectives

The students can…

  • explain the various parts of a cycle helmet and their functions
  • describe the role of models in science
  • comment on the strengths and weaknesses of the egg drop activity as a model.
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