Hypothesis: Cold water and hot water in identical environments will freeze at significantly different speeds, with the cold water freezing first and the hot water taking perhaps twice as long.

Protocol:

1. Start with two identical fourteen cube ice trays.
2. Fill an electric kettle with one liter of water and bring it to a boil.
3. Fill six cells on each of the trays with the boiling water.
4. Let the water rest one hour to return to room temperature.
5. Reboil the remaining water.
6. Fill six more cells with the boiling water. Skip block of four cells in center of tray to avoid thermal interaction.
7. Place trays in freezer. Swap one tray end for end so that one tray is hot in the back and cold in the front, and the other is reversed.
8. Check every fifteen minutes for freezing status.

Time	Comments	Image
-65	Empty Ice Trays
-60	Hot water added to cold side. The cold side is to the right in this picture, you can see that the icetray curves out a bit on that side, and is marked with an embossed "-" sign.
-60	Check Temperature with a thermometer. It was hotter, I had to look for the thermometer. Yeah, I should have had all my tools available before I started.
0	After an hour, it is cool. Room temperature at least.
0	Reboil and add hot water to hot side. Water from the same sink pull is reboiled in the same pot and added to the slots on the left. I am leaving the two middle cells open to provide some separation.
0	Check Temperature with Thermometer. Around 190 farenheit.
0	Place in freezer. The tray on the right is hot in the back and cool in the front, the one on the left is reversed to avoid any bias in the freezer
0	Check at fifteen minutes. No apparent freezing
0	Thirty minutes. Some ice crystals apparent in some of the Cold Side trays(lower right and upper left), nothing on the hot side.
45	Fourty Five minutes. Definite crystals in cold side cubes. A few on the hot side, especially upper right.
45	One Hour. Crusts starting to form on most cubes, on the cold side. Hot side has crystals, and a few crusts.
75	One hour, fifteen minutes. Most cold side cubes completely iced over, some looking mostly solid. Hot side crusted over.
90	Hour and a half. Lots of cold cubes looking solid. A couple of the hot side too, rest completly iced over
120	Sorry, the 105 minute pictures are crap. I am including just for completeness.
120	Two hours. Enough to call it complete. Pretty much all the cold side cubes are solid all the way through, as are some of the hot side ones.

My conclusion from this test is that water that starts cold freezes faster than water that starts hot. But the difference was not a much as I would have expected.