Invisible radiation question

The word "light" means both Visible and invisible radiation with any wavelength. I understand, but how is the invisible radiation? Why is it invisible?

Don't use hard words this time too please and thanks :)

Light that we can see changes the chemistry of the retina of our eye sending electrical impulses to our brain. The different frequencies of light represent different colours. Red is a low frequency and blue is a high frequency. Higher than blue or lower than red and our eyes can't detect it even though it's there.

Beyond blue (technically beyond violet) is ultra violet, just becasue we say it's invisible because our eyes can't see it doesn't mean it's truly invisible - for example bees can see ultra violet lights. In the same way frequencies of light that are lower than red can't be seen with our eyes, we call it infra red, but again just because we can't see infra red doesn't mean it's invisible to every creature on Earth - snakes for example can see infra red. We can feel infra red though on our skin as heat on a nice day when you feel the warm sunlight on your face - that's infra red.

The complete range of "colours" or frequencies of invisible light go from lowest frequency to highest:

Radio waves (as in what you tune into when you listen to the radio, this is the lower frequency, the upper frequency of radio waves is your analog terrestrial TV).

Micro waves (these are higher frequency, they're the same thing you cook your dinner with in your microwave oven and they're the same thing that mobile phones do - hence the irrational fear from people who don't have a scientific background about cooking their brains with a mobile phone).

Infra red (good old fashioned heat - like what you cook your dinner on a conventional oven with or what is emitted from the radiators in your home - also a lot of TV remote controls use infra red).