What is an effective way to shield against alpha particles?

Alpha particles are relatively large, positively charged particles that are emitted during certain types of radioactive decay. Their size and charge give them limited penetration power compared to other forms of radiation. As a result, they can be effectively stopped by very thin materials.

Using a sheet of paper or even a few inches of air can completely shield against alpha particles. This is because alpha particles can only travel short distances in air (a few centimeters) and are unable to penetrate solid materials like paper, while materials like lead or concrete are more than what is needed for alpha radiation.

In contrast, the other methods, such as using several meters of lead or a thick concrete wall, are excessive and not necessary for alpha particles. Alpha radiation does not require such dense or thick barriers to ensure safety. Similarly, while a double layer of clothing can provide an additional barrier, it still does not compare to the efficacy of just a sheet of paper or air for blocking alpha particles. Therefore, using simple materials efficiently addresses the issue of alpha radiation shielding.