Ionizing and Non-Ionizing Radiation

0:00Why can X-rays damage our DNA, when radio waves cannot?

0:05Radiation is energy that travels as waves or fast particles.

0:10The waves form the electromagnetic spectrum: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays.

0:21Toward gamma rays, the waves get shorter and carry more energy.

0:26With enough energy, radiation can knock an electron right off an atom.

0:31Now the atom has a positive charge, which makes it an ion. So this radiation is called ionizing.

0:39The dividing line falls inside the ultraviolet. The highest-energy ultraviolet, X-rays and gamma rays are ionizing.

0:48Alpha and beta particles, given off by radioactive atoms, are ionizing too.

0:54Ionizing radiation can also break DNA in our cells.

0:59Radio waves, microwaves, infrared and visible light are non-ionizing: they can heat things, but cannot knock electrons off atoms.

1:09The ultraviolet, or UV, in sunlight and tanning beds is not strongly ionizing.

1:16Even so, it can still damage the DNA in skin cells directly.

1:21Three basic ways protect you from ionizing radiation: less time, more distance and shielding.

1:29Lead makes a good shield, like the lead apron you may wear for a dental X-ray.

1:34A common myth says microwave ovens make food radioactive.

1:39In fact, microwaves make water molecules in food move faster, which heats it.

1:46So only ionizing radiation has enough energy to knock electrons off atoms.