What is a common characteristic of alpha particles?

Alpha particles have a unique characteristic that distinguishes them from other types of radiation. Being relatively large and positively charged, alpha particles consist of two protons and two neutrons, making them heavy compared to other radiation types such as beta particles and gamma rays.

Their larger mass and charge give them low penetration ability; they can only travel a short distance in the air—typically just a few centimeters—and are unable to penetrate materials effectively. In fact, they can be completely stopped by something as thin as a sheet of paper or the outer layer of human skin. This physical property is crucial for understanding radiation safety, as it indicates that alpha radiation poses little risk from external exposure but can be hazardous if ingested or inhaled.

By recognizing this characteristic, one can better appreciate the safety measures needed when working with radioactive materials that emit alpha particles, as the focus will be more on ingestion or inhalation rather than external exposure prevention.