What Is Radioactivity Used For?
A natural process that occurs in unstable atoms, radioactivity, when properly used, delivers many benefits. The reliability of radioactive decay makes it useful to estimate dates on ancient objects. Nuclear power plants use the energy of radioactivity to generate electricity. The penetrating power of radiation makes it indispensable in medicine and industry.
Power
Radioactive decay in uranium and plutonium fuel rods creates large amounts of heat. In a nuclear power plant, the heat is used to boil water and drive a steam turbine. The turbine runs an electric generator. A nuclear reactor uses no fossil fuels and produces no greenhouse gases. Some of the radioactive waste products are reclaimed for medical, educational and industrial use.
Illumination
In the early 1900s, watch and clock makers painted the dials with radium. This made them glow in the dark, but the dangerous radioactivity had serious health consequences. Today, exit signs and other items use tritium for the same purpose. The tritium doesn't give off light by itself; it's sealed in a phosphor-coated package and the coating glows. Tritium is far safer than radium for this use and can glow steadily for decades without electricity.
Medicine
Radioactivity is used for both medical diagnosis and treatment. Special radioactive marker compounds can be injected or eaten and then imaged in the body. A physician can then see problems with blood flow or intestinal blockages.
Many cancer treatments rely on radioactivity to kill tumor cells. In brachytherapy, a surgeon implants a small pellet of radioactive material inside a tumor. Over time, it is destroyed.
Science
The predictable decay of natural radioactivity lets scientists date ancient objects. They use different radioactive elements for longer and shorter time scales. Carbon-14, a radioactive isotope, is used to date the remnants of living things up to about 60,000 years. Isotopes of uranium, thorium, and other elements are used to date rock formations. They take millions or billions of years to decay, so they're better suited to geological time scales.
Detection
Neutrons, a highly penetrating form of radiation, are used to detect the presence of chemical compounds. This is a sensitive technology, able to discern to parts per billion, depending on the substance. When a sample is exposed to neutrons, each element reacts by giving off unique radiation of its own. Criminal investigations, which sometimes deal with tiny evidence samples, have benefited from neutron-activation analysis.
Tags: ancient objects, time scales, used date, What Radioactivity, What Radioactivity Used
