Alpha and beta are both types of particle decay that occur in radioactive substance. A radioactive substance is one which has an unstable nucleus, which causes it to emit mass and energy until it reaches stability.
An alpha particle is larger, slower and has a lower ionization capability than a beta particle. An alpha particle is equivalent to a helium nucleus. On the other hand, beta particles have greater speed and ionization capability, but they are much lighter, with a mass equivalent to that of an electron.
The third type of radiation is gamma radiation.
