Question: Why can we not see , hear or smell rediation?

Stephen Rhatigan answered on 7 Nov 2017:

Radiation is a general term which means energy in motion and includes waves and moving particles.
Light is a form of radiation so technically everything we see is radiation as light bounces off objects and reaches our eyes.
Sound waves are another form of radiation which we can hear.
Different animals evolved to be sensitive to different ranges of light and sound radiation. We can’t hear everything a dog or cat hears. We have evolved to detect only a very small fraction of the radiation that is all around us all the time.
We can’t see, hear or smell most of the radiation because we have not evolved with the ability to do so.
This makes it important to develop devices which can detect the forms of radiation which we cannot, especially the harmful forms of radiation.