/sci/ - Science & Math

>>6931221
Radiation is just a general term for electormagnetic waves. Electromagnetic radiation can come in different wavelenghts (see picture) or frequencies (frequency = 1/Period = speed of light/wavelength), a small part of which makes up the optic spectrum (i.e light, or radiation that you can see).

Radiation with high frequencies (and therefor short wavelenghts) contain more energy than low frequencies, since they "jiggle" around faster.

Lower frequencies than the optical spectrum are heat radiation, and then radiation to transmit FM and AM signals.
Higher frequencies are used for X-ray, and then comes the very high gamma radiation that you see with radioactive decay or fusion processes.

Now for radioactivity:
Radioactivity is just a term that describes _materials_, i.e atoms that decay into more stable (lower engery) levels, and therefore give away energy and/or particles (alpha/beta decay). There's also the case where an atom gets into an excited state (with higher energy), and drops back to its normal state where it gives off the energy by EM radiation (gamma decay). This energy is usually in the "gamma" part of the spectrum, very high Energy EM radiation, and can therefor do a lot of harm to living things.


An important distinction: Radiation itself never is "radioactive" (which really is just pseudo-greek for "emitts radiation"). Atoms are radioactive, because they can send out radiation.