The electromagnetic spectrum: examples

To understand any of this, we first need to finally deal with what an EM wave is.
Radiation of a point source : E field, and for an antenna. Here's a bigger picture.

An important question: so how does this radiation actually interact with matter?
What matters for us now is “absorption” (and then “resonance” gets involved).

Let's look at what these notions mean and entail: start from the middle – infrared

• ‘infra-red’ waves are absorbed by many materials; here is an example of a security use.
• Molecules get moving – and this is heat!   Our stove or oven, from the Sun, body heat ...
• It isn't as readily absorbed by smaller molecules ... and snakes are happy about this fact.
  As well as users of night-vision goggles and cameras.   Note the ‘division of labor’ here!

What about other frequences ... for example, lower ones (slower oscillations) ?
Like ‘microwave’ ?   It happens to make molecules of water rotate.
An example: a laser lab.   And how it may not work when it rains.