Suppose the initial temperature of a substance is 0 degree celsius. The temperature then increases, to 20 degree celsius.

So here's the question. What is the temperature difference between the two, in Kelvin?

I photographed several images looking from the Sandbanks peninsular towards Hengistbury Head and beyond with the attached images being the result.  The building do not appear to be anywhere within several miles of the headland in the picture and the distorted rock strata suggest the are a mirage.  What conditions lead to this effect and over what sort of distances can an image be seen?  The additional photos of boats show an inverted and a correct way up image above the sea surface - Is this the resut of the same conditions ?