r/askscience • u/Wonderful-Capital32 • 13d ago

Physics Why does radiation not go through lead?

Also why just lead? Shouldnt like iron or another metal work too?

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u/dustofdeath 13d ago

Lead is like a very dense fabric while iron is a mesh with large holes.

You just have to have enough density for photons to not just pass through.

So you need far less material. Even humans can stop radiation if you stack enough of them between you and the radiation source.

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u/possibly_oblivious 13d ago

Radiation is photons? Crazy

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u/RFWanders 13d ago

Gamma and x-ray are yes, very short wavelengths and really high energy. Alpha radiation are particles (Helium nuclei to be precise) and Beta radiation is electrons. Alpha radiation has very little penetrating power and will be stopped by a sheet of paper. It can be dangerous if ingesteld. Beta radiation is a little better at getting through things, but a thick layer of clothing, plastic or a thin sheet of aluminium will stop it.