How is radioactivity spread/contaminating anything that it comes into contact with?

Question

Just finished watching Chernobyl, and I’m curious what the effect/process is by which radioactivity is spread from one human/surface to another? What particle is responsible?

Thanks

In: Physics

Answer 1

We always explained it like this “it’s like stepping in dog shit. The smell is radiation, the shit is contamination. You can eventually clean off or sequester the shit, but you can’t do anything about what you already smelled.”