how do thermos flasks know whether they should keep something hot or keep something cold??

Question

if you put a hot drink in a thermos flask it keeps it hot - if you put a cold drink in in keeps it cold. How does it know whether it has to keep something hot or whether it should keep it cold? also can you buy separate thermos flasks - one that only keeps things hot and one that only keeps things cold - to avoid any confusion?

Answer 1

There is a heat sensor that transmits data to a central processing station. Where a small aboriginal man sits. The man is blown air in his face with the corresponding temperature of the substance in the thermos. If the man reacts by putting on his jacket the substance is obviously cold, if the man reacts by drinking a glass of water or fanning himself the substance is obvisouly hot. A camera captures the mans reaction and relays the reaction to a room of scientists who record his reaction and press a button to tell your thermos to keep your substance hot or cold. The message is relayed via satellite and 1000 nanosized motors run to keep your substance in the thermos either hot or cold.

Answer 2

stiggus dumpus,

A thermos is not "pre-programmed" in some way to keep things either hot or cold, it is simply a container made of a material that conducts heat very poorly. So whatever temperature your drink is at when you first put it in the thermos, it will tend to keep it at that same temperature (whether it is hot or cold). If it's hotter than the surrounding air, then heat will leak out of the thermos, but only very slowly. If it's colder than the surrounding air, than heat will leak INTO the thermos, but only very slowly. In any case, the thermos sheilds your drink from changes in temperature.

So basically, the thermos is not a heater or a cooler, but a "temperature keeper". I hope this answers your question!

Answer 3

They don't "know" anything -- thermos bottles are inanimate objects.

The thermos works because:

1) the vacuum of the thermos bottle acts as a superior insulator, preventing the conductive transfer of heat between the interior and exterior of the bottle,

2) the top prevents the convective transfer of heat by sealing any possible air flow, and

3) the reflective surface prevents radiative heating or cooling by reflecting the heat back towards its source.

No transfer of heat by any of these mechanisms means that hot contents retain their calories for longer, and cold contents are protected from heat for longer.

No need for two thermos bottles unless you are carrying one hot item and one cold item, or two hot items that you don't wish to mix (say coffee and soup), or . . .

Answer 4

Each thermos has its own built-in extra-sensory thermal sensing device that records the temperature & actually tells the thermos what to do.

Haha- Not really! lt just maintains the original temperature of the beverage b/c of the insulation, which does not allow heat exchange w/ the outside air (or at least, keeps it at a minimum).

Answer 5

Heat moves from hot to cold by conduction, convection and radiation. A Thermos bottle stops the flow of heat. It stops heat flow by conduction by have different layers that do not conduct. It stops the flow by convection by having a top so currents can not escape. It stops the escape of heat by radiation by being white or silver on the inside and reflecting the heat rays .Heat will slowly move in or out, but by stopping heat movement by all ways heat moves , thermoses keep our products hot or cold.

Answer 6

it insulates the substance from the environment. This means that less heat flows into or out of the thermos

Answer 7

it doesnt have to figure it out it either keeps some thing cold or hot does not matter insulation just works on its own