The following image is from the Wikipedia Article on Thermal Conductivity:
Please click here if you want a good image resolution, as I was unable to upload it here due to "Unsupported Image Format".
There is no description given about this image in that article. I also searched the internet, but did not get any relevant information. So, I tried to analyse the image on my own.
I concluded that the horizontal blue lines on the top of the diagram represent the uncertainity in values due to variation in the definitions of the materials. Could you please tell whether this conclusion is correct?
Further, could you please explain what does the height of the vertical blue lines represent? I am unable to think of any significance to their heights?