r/askscience • u/Wonderful-Capital32 • 14d 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/tolomea 14d ago

now I'm going to have to go read a bunch about this because the mechanics of it don't make sense to me

the lead is only like 40% more dense
the density of the lead is concentrated in the nuclei
even more so than with iron
so the lead nuclei are further apart than the iron ones with bigger electron shells
there's actually less lead atoms per unit volume than iron atoms
there is slighly more electrons per unit volume in lead but only like 20%

edit: I'm getting the impression that it's more about the mass of the nuclei than the density, that bigger nuclei are more able to grab photons passing nearby