Tell me about 'Invisibility and the Environment"?

Question

Tell me about 'Invisibility and the Environment'

Answer 1

Invisibility by environment
An object may be classified as "invisible" if it cannot be seen due to environmental factors other than the fact that it doesn't reflect light. An object that might normally be seeable may be classified as invisible if it is:

Behind an object.
The same colour or pattern as the background. (Camouflage)
Patterned so that its outline is hard to determine.
In an environment which is too dark or too bright.
Not in a particular observer's line-of-sight. (Especially when driving)
Transparent. (air and many other gases