Electromagnetic Non-Ionizing Radiation

• Beginning with the sun, which generates radiation in the form of heat and light, electromagnetic radiation surrounds us in their daily lives. Heat, light, sound, radio waves and other forms of energy travel in waves, the size of which is described in frequency. The Earth's electromagnetic fields support communications and cause the movement of weather patterns. The lowest-frequency radiation is often easy to see or feel in light bulbs, toasters and communication and entertainment devices.
  
  

Electromagnetic Ionizing Radiation

• Higher frequency radiation, called ionizing energy, has enough energy to change the molecules of the materials through which it passes. X-rays, gamma rays and cosmic rays all alter materials as they travel through space. Some, such as X-rays, are useful. They pass through flesh and bounce off denser matter -- bones or tumors -- and alter a film used to record their passage. Cosmic rays can disrupt radio and television broadcasts by disrupting Earth's electromagnetic field. Although electromagnetic non-ionizing radiation affects living tissue, growing tissue can often withstand or recover from minor exposures to electromagnetic ionizing radiation.
  
  

Ionizing Radiation

• Ionizing radiation makes possible the nuclear plant that generates power and nuclear medicine but also Fat Man and Little Boy, the weapons that ended World War Two in Japan. Large atoms with many protons gain and lose electrons, making them unstable. As unstable atoms move along waves, they gain and lose electrons and lose protons until they form a stable form, or ion. Unstable atoms damage living tissue by snatching electrons or shedding them as they pass through. Unstable atoms are found in soil, plants and people. The largest natural source of Ionizing radiation is radon gas that filters up through buildings.
  
  

Microwaves

• Microwaves are on the far end of the range of the electromagnetic range of non-ionizing radiation. They are similar to radar waves. Microwaves push molecules out of their way in liquids but cannot penetrate denser materials such as metal. When an area is flooded with microwaves, such as in a microwave oven, molecules in less dense materials bounce off each other. As they move faster and faster, they generate heat. High concentrations of microwaves can cause burns, but appliances such as microwave ovens are shielded to prevent leaks. Although microwaves were once considered a threat to heart pacemaker operation, the American Cancer Society says that microwave shielding protects modern pacemakers.