Science activity
How Helmets Protect Your Head: Force and Cushion
Learn that helmets keep your head safe when you ride or play.
Materials and setup
- two eggs (optional egg-drop demo)
- bubble wrap
- foam
- ruler
- notebook
How this changes by age
Pre-K (ages 3–4)
Learn that helmets keep your head safe when you ride or play.
Steps
- Show your child a bicycle helmet. Let them put it on.
- Ask: What does this do? Why do we wear it?
- Explain: If you fall, the helmet has soft padding inside. The padding absorbs the bump so your head doesn't get hurt as much.
- Name two times when you should wear a helmet.
Learning objectives
- Know that helmets protect the head from injury
- Identify activities where helmets are needed
Kindergarten (ages 5–6)
Learn why the soft padding inside a helmet makes bumps hurt less.
Steps
- Tap your hand on a hard table. Ouch!
- Now put a pillow or soft cloth between your hand and the table and tap again. Less ouch!
- Explain: That's what a helmet does — the foam padding slows down the bump. A slower stop hurts less than a sudden stop.
- Ask: What other things do we use to slow down a bump or a fall? (Car seats, padding, mats, etc.)
- Draw a helmet and label the hard outside and the soft inside.
Learning objectives
- Understand that padding slows down impact
- Know that slower stops cause less force
Early elementary (ages 6–8)
Investigate how helmets reduce force by increasing the time of an impact.
Steps
- Learn the concept: When your head hits something, the force depends on how FAST the stop happens. A quick stop = big force. A slow stop = smaller force. Helmet foam compresses to slow down the stop.
- Test it: Drop an egg from waist height onto a hard floor (outside or with newspaper down!). Now wrap an egg in bubble wrap and drop it from the same height. What happens?
- The bubble wrap acts like helmet foam — it slows the impact over more time.
- Discuss: Why do helmets have a hard outer shell AND soft foam inside? What does each part do?
- Name three sports where helmets are used. Why is head protection especially important in each?
- Write: 'Helmets protect your head because...'
Learning objectives
- Understand that longer stopping time means less peak force
- Connect the egg-drop demo to how helmet foam works
- Identify the two-layer structure of helmets (hard shell + soft foam)
Upper elementary (ages 8–10)
Apply Newton's Second Law and the impulse-momentum theorem to explain how helmet design reduces head injury.
Steps
- Learn the physics: Newton's Second Law says F = ma. Force equals mass times acceleration (or deceleration).
- The impulse-momentum theorem says: F × Δt = m × Δv. If you want to reduce peak Force (F), you can increase the time of impact (Δt). Helmets do exactly this — the EPS (expanded polystyrene) foam compresses slowly, spreading the impact over more time.
- Calculate an example: If a head of mass 5 kg decelerates from 5 m/s to 0 in 0.002 seconds (no helmet), what is the force? Now calculate for 0.02 seconds (with helmet). (F = m × Δv / Δt)
- Research EPS foam: Why is it used in helmets? How does it compress and absorb energy? Why can it usually only be used once?
- Engineering trade-offs: A thicker helmet absorbs more energy but is heavier and hotter. A lighter helmet may not protect as well. Research how different sports optimize these trade-offs (bicycle helmet vs. football helmet vs. hockey helmet).
- Write: 'Helmets use the impulse-momentum theorem to reduce injury because...'
Learning objectives
- Apply F = ma and F × Δt = m × Δv to helmet design
- Calculate peak force with and without a helmet
- Explain why EPS foam is used and why it is single-use
- Analyze engineering trade-offs in helmet design across sports
Safety and evidence note
Read the full activity before beginning. An adult should supervise tools, heat, food, outdoor work, movement, and experiments as appropriate. Completion records that the activity was done; the child’s explanation, work sample, photo, or demonstration is stronger evidence of learning than a completion check alone.
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