Why does cotton wool stop radiation?

Cotton wool can help reduce radiation exposure primarily through its physical properties. While it doesn't stop radiation completely, it can attenuate certain types of radiation, such as alpha particles and some beta particles, by providing a barrier that absorbs or scatters the incoming radiation. However, for more penetrating radiation like gamma rays or X-rays, cotton wool is ineffective, and denser materials, such as lead or concrete, are needed for adequate shielding.