What is radiation?
Radiation is energy that travels through space as waves or particles. It includes visible light, radio waves and microwaves, as well as higher-energy forms like X-rays and gamma rays.
Scientists divide radiation into two types. Non-ionizing radiation, such as radio waves, microwaves, infrared and visible light, has relatively low energy. Ionizing radiation, such as X-rays, gamma rays and particles from radioactive materials, has enough energy to knock electrons off atoms and damage living cells and DNA.
We are exposed to small amounts of natural radiation every day, called background radiation. It comes from rocks and soil, radon gas, cosmic rays from space and even some foods. Medical X-rays and CT scans add more but are used because their benefits outweigh the small risks.
Uses and safety
Radiation has many uses, from cooking with microwaves and communicating by radio to treating cancer with radiotherapy and generating electricity in nuclear power plants. People who work with ionizing radiation wear protection and badges that track their exposure.
Did You Know?
Marie Curie, who pioneered research on radioactivity, won Nobel Prizes in both physics and chemistry. Her notebooks are still radioactive and kept in lead-lined boxes.