How do we know what a material is just by looking at it?

[kolleamm]

TL;DR Summary

identifying materials just by looking at them

I find it really interesting that I can look at an image of rubber and know immediately its rubber, and then look at an image of a metal and know its a metal. How do we reach such conclusions? My first guess is the smoothness of the material's surface, but maybe there's other features I'm missing here.

Would like to hear your thoughts on this.

 

[Drakkith]

Color, smoothness, shininess, brightness, and texture are the first things that come to mind for me.

 

[Rive]

Summary: identifying materials just by looking at them

Would like to hear your thoughts on this.

Sometimes you just can't

 

[pinball1970]

Summary: identifying materials just by looking at them

I find it really interesting that I can look at an image of rubber and know immediately its rubber, and then look at an image of a metal and know its a metal. How do we reach such conclusions? My first guess is the smoothness of the material's surface, but maybe there's other features I'm missing here.

Would like to hear your thoughts on this.

This is a biology question in my view, developmental biology.
You learn what things are and relate to those properties for that object.
All the properties mentioned by @Drakkith
The knowledge is learned applied and refined, just like learning to read.
One can get it horribly wrong too don't forget, ever picked something up thinking it was one thing and it turned out to be something else?

 

[Klystron]

How do you identify anything from an image?

Post #2 describes the physics and #4 biology. We learn to recognize objects from images as young children immersed in our cultures. I do not remember seeing my first photograph but I do remember seeing drawings in books that were described as Tree, Ball, Sun, etc.

Learning to read was easy. My father recited from the Bible tracing the words with his finger while I dozed in his lap. At some point the squiggles became words and I could read print from then on.

Television was a different learning experience. Blobs of moving silver and gray resolved to images 'if I let them'. As a child I could see the raster scan on a black&white NTSC television screen.

Years later I went through a similar learning experience learning to discern signals on a radar screen displaying raw data signals as light blips on horizontal "grass" against a green phosphor background. Some (rare) people could not recognize the signal at all. Others could learn to recognize an aircraft return from a bird in flight and know aspects of relative motion.

Behavioral psychologists such as B.F. Skinner study perception. See also 'foreground and background'.