If You Were Stuck on an Island, How to measure Heat?

So I was reading this:

Determining whether or not hot water can freeze faster than cold water may seem like a no-brainer. After all, water freezes at 0 degrees Celsius. And wouldn’t water hot enough to kill E. coli bacteria (about 120 degrees Fahrenheit or 50 degrees Celsius) take a longer path than cooler water at a fall New England beach (about 60 degrees Fahrenheit or 15 degrees Celsius) towards a frigid future as ice

Ok, so 120Fareingheight kills e-coli.

Then I started thinking imagine if I was stuck on an island with taco bell food.
What would I do?

Anyhow my question is... if your stuck on an island and want to heat food how do you measure what's 120Fareinheight?

Is there any way?

Thx

If you instinctively pull your hand away at the touch if it, it is probably hotter than 120 degrees. There are ways to make home thermometers the MacGyver way, but its a hassle, in a survuval situation, it's best to cook anything well done or more. Parasites are notorious in those tropical areas.

One Idea I found goes a little like this:

1. Fill a small clear plastic or glass bottle with a narrow opening at the neck of the bottle about halfway with rubbing alcohol.
2. Fill the remaining space in the bottle nearly to the top with water.
3. Add a few drops of food coloring to the water / alcohol mixture. Cover the top of the bottle and shake lightly to blend the coloring evenly.
4. Place a straw into the bottle.
5. Use clay or sealable moldable material to surround the straw at the opening of the bottle. Wedge the clay in so that it holds the straw in place and keeps the bottle closed, but does not squeeze the straw closed. Lift the straw up about ¼ of an inch, so it is not resting on the bottom of the bottle.

Your thermometer is ready. Mark the level of the liquid at room temperature and closely monitor the level of the liquid. Mark lines on the straw when you put the thermometer in warm and cold locations. When the liquid in your thermometer gets warm, it expands and takes up more space. So, the liquid moves up through the straw when once it gets warmer.

While your thermometer may not be as accurate as a commercial model, you should be able to easily see the effects of the temperature changes on it.

The Fahrenheit scale measures 32 degrees when water freezes and 212 degrees when water boils.

LOL you idiots (jk)

If your stuck on a island, then you eat what you catch and you start a fire any way you can....you cook the food on the fire in the coals....(All quite dirty)
e-coli will be the last thing you think about.....
No soap either so you prob had to wipe your behind on a leaf and you have to eat with the same hand/s

Come on this thread is a Gee up yer, you can not be serious.

Originally posted by 297GT
LOL you idiots (jk)

If your stuck on a island, then you eat what you catch and you start a fire any way you can....you cook the food on the fire in the coals....(All quite dirty)
e-coli will be the last thing you think about.....
No soap either so you prob had to wipe your behind on a leaf and you have to eat with the same hand/s

Come on this thread is a Gee up yer, you can not be serious.

You know..that may be true..but there are still legitimate questions when dealing with survival, and as much as I DO know, quite honestly I never thought of this until the thread was posted.
Never assume you know everything.
It's the little things that could be your own undoing when it comes to survival..
Remember Christopher McCandless?
Google.