From One To The Other

[Bazile]

- At what point does light become dark ?

- At what temperature does cold become warm - warm become hot

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[Quizmonster]

During Ramadan, the Muslim fasting-month, senior clerics used to decide it had become dark...ie the faithful could eat...when they were unable to distinguish between a black thread and a white one. They may well still do.
Not a very scientific answer, but it may interest you.

[gingejbee]

Light, dark, cold, warm, hot....are all approximate, non-numerical descriptions of the states that they describe. You simply cannot give them numerical values...

[VHG]

or easy become hard, or hard becomes soft, or quiet becomes noisy.

There are loads of them.

There is not fixed point, just graduations.

[EcclesCake]

Something that has always intrigued me is the use of the word 'mild' by weather forecasters. In the winter it means it is going to be warmer than preceding days and in the summer it means it is going to be cooler.

[Fitzer]

In the Royal Navy during the Napoleonic wars, day was deemed to have arrived when one 'could see a grey goose at a mile' :-)

[gingejbee]

^^Eccles...you know it's going to be warmer when the temperatures miraculously are given in Fahrenheit as well as Celcius!

[jim360]

Transition points aren't necessarily gradations, and can in fact be incredibly sharp on occasion. However questions like "light" and "dark" or "cold", "warm" and "hot", are more about perception than anything precise and scientific. If I were to assign meanings to the last three I would probably say something like "cold" is a region where effects of temperature can be neglected, "warm" is where they start to matter, and "hot" would be when temperature effects are dominant. Where these start and end (roughly) will depend on the system in question, but the behaviours across each region need not be smoothly varying one to the other.

[stuey]

I was amazed the first time I encountered a thermocline while SCUBA diving. Descending slowly, my face suddenly became very cold while the rest of my body was still relatively warm...There was a distinct "line" in the water between warm and cold.

[wildwood]

If you go outside from a warm house the outside can be quite cold, but to someone already outside it is mild. Using that logic there can be no exact point where one becomes the other.

[Hypognosis]

With regard to light and dark, there does come a point where, instead of detecting a solid beam of light, it is reduced to mere "scintillation": a random-looking scatter of individual photons. Night vision uses a neat trick whereby one arriving photon sets off a cascade reaction of secondary photons and that creates enough signal for normal amplification circuitry to work on. Anyway, to my mind, the division between light and dark is: either a photon is arriving on your retina or the gap between it and the next arrival is reaching your retina.

Cold warm and hot are subjective and, if you don't mind confining the meanings to "relative to mammalian physiology", you could allow individual skin nerve endings to determine the trigger points of cold and hot for you, with warm defined as the point where both cold and hot sensors are putting out minimal signals at the same time. Regrettably, even my trusty old textbook doesn't have that level of detail.

[Old_Geezer]

They're subjective Baz. You decide.

[naomi24]

I don't know the answers - but what a good question!!