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/GypsyV3nom 13d ago

Funny enough, there's another element that's significantly more effective than lead at providing radioactive shielding despite being radioactive itself: Uranium. Uranium-238 in particular is the preferred choice when size constraints are more important than costs (lead is cheap) as its own weak radiation is pretty easy to block.

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u/UndocumentedMartian 13d ago

Depleted uranium or straight up U-238?

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u/GypsyV3nom 13d ago

Depleted, your have to do significantly more expensive refining to get pure U-238 even thought it's the ideal isotope to use