Everything in a given environment have the same temperature

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    Temperature
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Discussion Overview

The discussion revolves around whether all objects in a given environment, such as a refrigerator, have the same temperature when they have reached thermal equilibrium. Participants explore the implications of material properties on temperature perception and the factors influencing human sensation of heat and cold.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants assert that if objects are in thermal equilibrium within an ideal refrigerator, they will all read the same temperature, assuming sufficient time has passed.
  • Others argue that in practical scenarios, achieving true thermal equilibrium is unlikely due to various factors, such as the refrigerator's design and operation.
  • It is noted that temperature readings do not account for how materials feel to the touch, as sensations of coldness depend on heat conductivity and specific heat capacity.
  • Participants discuss the phenomenon where materials at the same temperature can feel different based on their thermal conductivity, with metal feeling colder than plastic at the same temperature.
  • Some contributions highlight that the sensation of temperature can also be influenced by prior contact with different temperatures, affecting how heat or cold is perceived.
  • There is a contention regarding the relationship between heat transfer rates and temperature perception, with differing views on whether heat flows into or out of the hand more effectively based on the material's properties.

Areas of Agreement / Disagreement

Participants generally do not reach consensus on whether all objects in a refrigerator will have the same temperature in practice, as some argue for ideal conditions while others emphasize real-world limitations. There is also disagreement regarding the interpretation of heat transfer and sensation of temperature based on material properties.

Contextual Notes

Participants mention various assumptions about the refrigerator's operation, such as the airtightness of doors and the absence of heat radiation or absorption, which are not universally agreed upon. The discussion also touches on the complexity of human sensory perception, which is influenced by prior experiences and material properties.

Who May Find This Useful

This discussion may be of interest to those studying thermodynamics, material science, or human physiology, particularly in understanding the nuances of temperature perception and thermal equilibrium.

quasi426
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Does everything in a given environment have the same temperature. For example does everything inside a refridgerator have the same temperature like a cup of water and a block of steel and a plastic cup. (say the setting of the fridge is at 5 C degrees, if a thermometer is placed on all these items, will they all yield a 5 C degree temperature reading.) Of course assuming these items have been in the environment for a long time and the environment is using energy to maintain this constant temperature.
 
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The temperature does not depend on the type of material.
But, how cold something at a low temperature feels if you touch it depends on more than temperature. The coldness sensation also depends on the heat conductivity and the specific heat capacity of the material.. So steel at 5 C will feel colder than plastic at 5 C, because the heat flow into your hand is faster.
 
I have an answer already formed in my head but I don't want to give it away.

Why don't you consider the system by which the fridge regulates its temperature - the thermostat etc, and if the doors are completely air tight, and if the fridge won't radiate or absorb heat etc.

NS
 
The answer is yes, they all have the same temperature if you wait
for everything to reach equilibrium- for an ideal fridge.

This will never happen in a real refridgerator for all the things you cited.
 
Last edited:
Meir Achuz said:
The temperature does not depend on the type of material.
But, how cold something at a low temperature feels if you touch it depends on more than temperature. The coldness sensation also depends on the heat conductivity and the specific heat capacity of the material.. So steel at 5 C will feel colder than plastic at 5 C, because the heat flow into your hand is faster.

This is exactly what I was thinking. We feel heat conductivity and not temperature. Thanks. Does anyone have a biological reference?
 
An additional factor in human feeling of heat/cold is that whether something feels hot or cold depends in part on what a finger, for exampe, has touched previously. The standard experiment is to place a finger of one hand into a cup of hot water and the a finger of the other hand into a cup of cold water. Then place both fingers into a cup of luke warm water. The finger that was in hot water will feel cold while the finger that was in cold water will feel hot.
 
quasi426 said:
This is exactly what I was thinking. We feel heat conductivity and not temperature. Thanks. Does anyone have a biological reference?
I'm not sure if this is what you mean, but if you touch a piece of metal and a piece of wood, both at room temperature, the metal will feel cold and the wood will not. This is because our sense of touch/temperature depends more on heat transfer rate than it does on temperature itself.
 
reasonmclucus said:
An additional factor in human feeling of heat/cold is that whether something feels hot or cold depends in part on what a finger, for exampe, has touched previously.
Quite correct. The brain adjusts its sensory inputs over a period of time. An old bar trick, for example, is to secretly pinch an ice cube between your thumb and forefinger for a while, and then bet someone that you can hold a lit cigarette by the ember without flinching. As long as you restrict it to a few seconds, you won't feel the heat and it won't cause a burn.
Another thing that seems counter-intuitive at first is that frostbite and a burn are essentially the same injury and feel the same. Somebody like Moonbear would be best to follow up on this.
 
Meir Achuz said:
The temperature does not depend on the type of material.
But, how cold something at a low temperature feels if you touch it depends on more than temperature. The coldness sensation also depends on the heat conductivity and the specific heat capacity of the material.. So steel at 5 C will feel colder than plastic at 5 C, because the heat flow into your hand is faster.


Hmmm ... I am thinking it's the other way around. Metal, due to free electrons, conducts heat better than plastic. So heat will flow from your hand into the steal at a greater rate than it will from your hand to to the plastic.
 
  • #10
russ_watters said:
I'm not sure if this is what you mean, but if you touch a piece of metal and a piece of wood, both at room temperature, the metal will feel cold and the wood will not. This is because our sense of touch/temperature depends more on heat transfer rate than it does on temperature itself.


Yeah that is what I was saying. But I guess I said heat conductivity instead of heat transfer because they are similar.
 
  • #11
ddesai said:
Hmmm ... I am thinking it's the other way around. Metal, due to free electrons, conducts heat better than plastic. So heat will flow from your hand into the steal at a greater rate than it will from your hand to to the plastic.

Thank you. I did mean heat flow out of your hand.
Heat flow into your hand would be why hot metal in burns your hand, while wood doesn't.
 
  • #12
Final comment-

If your hand is 92 degrees then a 92 degree piece of wood and steel will feel
the same. I've tried it.
 
  • #13
I've noticed that sometimes when one has a fever, they may not be able to tell how bad of a temperature increase they have incurred when one feels their own forehead as opposed to someone else feeling it.
 

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