If hot air rises....

[wyldkhatdd]

If hot air rises....then why is the freezer on the top on the refridgerator and not on the bottom? Would it not make more sense to put it below the fridge...thereby not allowing the hot air to raise the temperature of the freezer?(conserving the energy the appliance would use to lower the temperature of the freezer)

[KebabMeister]

Could it be to assist convection currents to circulate around the fridge?  i.e. cold air sinking to the other parts of the fridge to assist chilling and when it warms it will then cause a circulation effect?

[ezapf]

There are refrigerators with the freezer on bottom. They seem much more expensive than the conventional or side-by-side ones. Don't know why.

[weaverca]

Convenience?

[eupraxia]

My freezer is below my firdge.

[NetSquirrel]

I believe the reason is, as weaverca says, for convenience.  Fridges are used more often than freezers, so it makes sense to put the fridge part in the most accessible place.  The way most fridge/freezers are arranged places most of the fridge's shelves between knee and shoulder height for the average person.  This makes it easy to access your most commonly needed items - milk, butter and so on.

As for hot air "rising"...well, this is a common over-simplification.  Hot air by itself does not "rise" - it is affected just as much by gravity as anything else.  Hot air is, however, less dense than cold air (the molecules in hot air are more spread out).  This makes it effectively lighter (per unit volume) than cold air.  Because of this, a pocket of warm air will "float" above any surrounding air colder than itself, much like the way a hot air balloon works, with the exception that free-flowing air will eventually mix with the cold air and the temperatures will equalise. 

...Which brings me to KebabMeister's answer.  Yours is a good theory and is probably correct to some extent, although there is quite a thick layer of insulation between the fridge and freezer compartments.  (I have pinched someone's photo of a fridge/freezer and modified it to show the heat transfer as seen here http://img201.exs.cx/my.php?loc=img201&image=answerbankfridgefreezernetsqui.jpg - I guessed the temperatures).

[Continued]

[NetSquirrel]

There would be a tiny bit of heat transfer across the insulation layer, but it would be neither beneficial nor detrimental to the distribution of heat in the freezer, as far as I can see.  A mild convection current would be set up as a result of having a temperature gradient, leading the food to be chilled more evenly...however, the lack of a temperature gradient shows that all parts of the freezer are already equally chilled, so the "problem" is self-fixing.  Switching the positions of the fridge and freezer would hardly affect the rate of heat transfer at all.

Finally (yes, I will shut up soon!) I fail to see how the efficiency of the fridge/freezer could be noticeably affected by the placement of the two compartments.  Electrical energy is used to cool both the fridge and freezer.  Even if some heat energy were to be transferred from the fridge to the freezer, there is no loss of efficiency.  The amount of extra cooling the freezer will require is exactly made up for by the "free" cooling the fridge receives.

Hope this helps, and sorry for the needlessly long answer.

[landie]

Neither is mine.

[rojash]

All these answers appear to assume that wyldkhatdd is talking about the juxtaposition of the fridge and the freezer components of a fridge/freezer combination. I could be wrong, but I suspect the question is actually about the ice compartment in a simple fridge. In which case KebabMeister has hit the nail on the head.
The ice compartment is effectively the "engine" that cools the fridge, so logically it lives at the top. The cool air then circulates by convection and cools the rest of the fridge.

[wyldkhatdd]

U all have really hepled thank you... now i can prove my physics teacher wrong about his theory that people were just lazy and put the freezer on top.(He thinks he found a mega mistake of the world...lol)

[hanna1234567]

coz they are in different bits so it can mke no difference?