Ernest Rutherford is credited with demonstrating the existence of beta rays in 1899.
While the discovery of radioactivity itself is attributed to Henri Becquerel, Rutherford's experiments helped to differentiate and characterize the different types of radiation emitted by radioactive substances. He showed that at least two distinct types of radiation were present: alpha and beta radiation. Through his experiments, he proved that beta rays were different from alpha rays based on their penetrating power and behavior in magnetic fields. Further research identified beta rays as high-energy electrons.
