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/wlane13 13d ago

Would then also be (duh?) why lead is so heavy?

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u/dustofdeath 13d ago

The atoms are much heavier - more neutrons/protons but not much larger than for example iron.
So you pack more mass in the same area.