h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

30 minutes. They both feel the same temperature.

40 minutes. Both dishes feel the same temperature.

50 minutes. Still not frozen

Nearly 2 hours. Still not frozen.. I give up !

you are now into the shadowy realms of latent heat!!!

I didn't think you were actually going to give up.

Both experiments were clearly not the right conditions anyway. It sounded rather like the cold one was going to freeze first from the descriptions.

Before turning in for the night I went out and checked them again. Both saucers were lightly frozen over. I think with the temperature only a little below freezing . It was taking so long for any ice to form the hot water had cooled down to the same temperature as the cold water. For this experiment to work I think it needs to be really cold.
It was interesting none the less.

I wonder if sticking your finger in introduced enough warmth to slow things down? Eh, now that it's typed out, probably not enough to matter, given the sensitivity of the measuring instrument.