We are able to see this beautiful world because of light. When light gets reflected from the object, the reflected light enters our eye retina and thus we are able see that particular object from which light was reflected from. In our daily life, we see certain things which are transparent, they appear transparent because most of the light is refracted instead of getting reflected. So, there will be only very less reflected rays which enters our eye and thus enables see up to certain extent. Suppose we have mirror or any other matter which is perfectly transparent, i.e it reflects no light incident on it. If this happens, we will not be able to see that particular object! So, if this is a possibility we can create invisible things like invisible robot, etc from those perfectly reflecting matter (like ideal transparent glass).
Is this really possible? If yes what kind of things would be better to create in invisible form, like one may show their idea by displaying their model (ex. spy robot). Every one can give their idea, so that there will be value of saying why this site is for scientists!
Best Answer
A transparent object, like glass or some plastics, is not invisible for 2 reasons:
The index of refraction is not the same as air. In fact, no solid material has an index close enough to that of air (I found some nano-materials having 1.1 compared to air's 1.0003). Thus, the refraction will distort the image and the object will be visible because of this distortion.
Even very transparent glass has some opacity. If you have a thin slice, it may seem transparent, but when you have a thick piece, it will absorb a significant portion of the light.