Assertion: radiation | /r/HasProperty | invisible
Facets:
Source sentences:
text: Since this radiation is invisible and not directly detectable by human senses, instruments such as Geiger counters are usually required to detect its presence.
text: However, because radiation is invisible and works inside your body, it can be hard to put your trust into a treatment you can’t see, touch or smell.
text: Since the radiation is invisible, special IR-proof goggles must be worn in such places.
text: This radiation may be visible or invisible to the human eye.