Materials that are radioactive are made up of atoms that contain excess energy. These radioactive materials give off their excess energy as radiation. The three kinds of nuclear radiation that come from the radioactive materials are alpha, beta, and gamma radiation. All three types are present in nature. They can be blocked by a sheet of paper.
Beta particles are high-speed electrons.
They can be blocked by a thin sheet of aluminum. X-rays are lower in energy and come from the electrons around the nucleus. Return to list. The health effects of very high doses of radiation are serious. They also are better understood than those of non-radiation hazards.