When the alpha particle is clearly visible.What is an alpha particle made of?

An alpha particle is composed of two protons and two neutrons, making it essentially a helium nucleus. It is emitted during radioactive decay processes, such as alpha decay, where unstable atomic nuclei release energy to achieve stability. Due to its relatively large mass and positive charge, an alpha particle has low penetration power and can be stopped by a sheet of paper or even the outer layer of human skin.