What can alpha particles penetrate through?

Alpha particles are a type of ionizing radiation consisting of two protons and two neutrons. Due to their relatively large mass and positive charge, alpha particles have low penetration power compared to other forms of radiation like beta particles or gamma rays.

Alpha particles can be stopped very effectively by just a few centimeters of air or by a simple barrier like sheet paper. This is because they interact strongly with matter due to their charge, losing energy quickly as they collide with other atoms. Consequently, they cannot penetrate through materials such as thick glass, lead, or wood, which can all provide much greater barriers due to their density and atomic structure.

The ability of alpha particles to pass through only a few particles of air and sheet paper highlights their limited range and power, confirming that this is the correct description of their penetration capabilities.