Level 7: Shielding

Radiation and the atom · level 7 of 8 · rough age 15-16 (a guide for parents; anyone can start anywhere)

A shield works by putting matter in the way. This level works out how much: how each kind of radiation loses its energy, how a gamma beam halves with each layer, and why the mass over each square centimetre matters more than the material. It ends with the question at the heart of this topic: how deep under Mars soil should a home be?

Lesson	You will be able to
How shields work	Explain how each kind of radiation is stopped or slowed
Half-value thickness	Use the half-value thickness to find what gets through
Mass per area	Compare shields by their mass over each square centimetre
Why hydrogen shields best	Explain why water and plastic beat metal against cosmic rays
Regolith shields	Work out the shielding from a layer of Mars soil
How deep to build	Plan a Mars home's shielding and a crew's dose

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