My fridge is cold enough such that a frozen bottle of water has remained frozen for three weeks, yet warm enough such that a bottle of liquid water has not frozen despite being in basically the same place. What's going on in there?

THE ANSWER IS OBVIOUS!

YOUR FRIDGE IS HOLDING A TEMPERATURE OF 32.1 DEGREES FAHRENHEIT. THIS IS NOT COLD ENOUGH TO FREEZE YOUR UNFROZEN BOTTLE NO MATTER HOW LONG YOU LEAVE IT IN THERE, BUT YOUR FROZEN BOTTLE WHICH WAS CHILLED TO A TEMPERATURE FAR BELOW 32 DEGREES BEFORE BEING PLACED IN YOUR FRIDGE WILL TAKE A VERY VERY LONG TIME TO COME TO A TEMPERATURE ABOVE 32.

UNLESS THE FROZEN BOTTLE FROZE AS A RESULT OF BEING PLACED IN THIS SAME FRIDGE. IN THAT CASE, YOU HAVE A MAGIC FRIDGE, AND SHOULD PROBABLY TRY TO SELL IT ON EBAY.

http://en.wikipedia.org/wiki/Refrigerator

Therefore you have your fridge on too cold - Optimum temperature range for perishable food storage is 3 to 5 °C (37 to 41 °F). At +3 degrees it should have melted. There's a knob somewhere in your fridge, turn it to another number - it's probably at one or other maximum setting now so turn it a bit closer to the medium setting

PLACEMENT WITHIN THE FRIDGE MATTERS TOO! FOR EXAMPLE, IN MY FRIDGE I HAVE A "REALLY ABNORMALLY COLD BEER" SPOT ON THE MIDDLE SHELF ALL THE WAY IN THE BACK. THIS IS WHERE I PUT A BEER WHEN I WANT IT TO GET REALLY COLD. THE REST OF THE FRIDGE IS THE "NORMALLY COLD BEER" REGION!

OH AND THERE'S SOME FOOD AND STUFF IN THERE FOR THE REST OF THE FAMILY.

HA!

i dont think this is as much a thermodynamics question as it is a way refrigerators work question.

i got one better than that. back when i lived with my parents, their full size garage freezer/fridge combo wouldn't keep things frozen during the winter, and worked fine during the summer. google that one and learn something.

http://en.wikipedia.org/...tent_heat_of_vaporization

This is what you are looking for to explain the delay in transition from solid to liquid.

It also applies to the transition from liquid to gas. Same priniciple in operation.

I've had bottles of water in liquid phase in my car while the temps are below freezing. I shake the bottle and I watch it quickly freeze into a solid slush.

Supercooling... with a little nucleation to get it going...

Example: https://www.youtube.com/watch?v=ZCEJ0QBiSv8
Example 2: https://www.youtube.com/watch?v=cgAlxBEPEf4#t=0

ON THE SAME OR SIMILAR TOPIC

MAGNETS

HOW DO THEY WORK

Water requires a considerable amount of latent energy to effect a phase change. This makes it great for storing energy, and lousy as a refrigerant. You can do a fun experiment to observe this by putting a pan of oil and a pan of water on a stove and timing the amount of time it takes each to raise a certain temp with the same amount of energy input. The operating temperature of your fridge is only part of the formula, the amount of energy being added or subtracted from the water also counts. In this case, not only is your fridge probably set a tad on the cold side, its also apparently a very efficient unit.

Trife, magnets are powered by witchcraft. It takes a certain amount of sacrificed chicken bones and sulfur to effect a magnetic field of a particular strength. For this reason, magnets tend to be much stronger in close proximity to large sources of witchcraft like Haiti, New Orleans, and Wall Street.

'For this reason, magnets tend to be much stronger in close proximity to large sources of witchcraft like Haiti, New Orleans, and Wall Street. '

bwahahahahahaha

nice!

ON A BETTER TOPIC: PALINDROMES: HOW DO THEY FAIL?

I can't comment, I have aibohphobia

*shivers*

Water that is contaminated by other substances (for example, salt, etc) have different freezing temperatures. Usually lower than usual.

Lol, I've never heard that one, that's good

^This!

Also, refrigerator position! Stuff in the upper front of my fridge is arguably too warm, and stuff in the lower back of my fridge is arguably frozen.....

the laws of thermodynamics as described in Michael Jackon's song: "The Whiz"
1) you can't win
2) you cant' break even
3) you can't get out of the game