Thermal equilibrium: Difference between revisions

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<onlyinclude>'''Thermal equilibrium''' is the state of a system in which its [[heat]] flow is balanced with its surroundings, meaning the [[temperature]]s of the system and surroundings are the same.</onlyinclude> A system at a higher temperature will [[heat transfer|transfer heat]] to a system at a lower temperature when they are in contact, until their temperatures are equal.<ref>Hyperphysics, ''Thermal equilbrium'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thereq.html</ref> Thermal equilibrium is an important concept for [[thermodynamics]] and [[blackbody radiation]], and is the subject of the [http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thereq.html#c2 zeroth law of thermodynamics].
<onlyinclude>[[Heat]] is the flow of [[energy]] from a high [[temperature]] to a low temperature. When these temperatures balance out, heat stops flowing, then the system (or set of systems) is said to be in '''thermal equilibrium'''.</onlyinclude><ref>Hyperphysics, ''Thermal equilbrium'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thereq.html</ref> The [[zeroth law of thermodynamics]] uses thermal equilibrium to define how two different systems can be said to be at the same temperature. For example, when molten rock comes up from a volcano, it will give off heat to the [[atmosphere]] until the rock and the atmosphere are at the same temperature. Even though the two systems (rock and air) are very different, thermal equilibrium allows a definition of temperature for both.


Thermal equilibrium is important for all heat transfer events, because it is what all systems will tend to over time. Knowing that interacting systems will tend towards the same temperature allows for important applications in all areas of science. For example, the [[specific heat capacity]] of a substance can be determined by placing it in water and measuring the temperature after a period of time.<ref>Hyperphysics, ''Calorimetry'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/calor.html#c1</ref>
All systems tend towards thermal equilibrium over time—and some systems will take a lot longer than others. Knowing that interacting systems will tend towards the same temperature allows for important applications in all areas of science. For example, the [[specific heat capacity]] of a substance can be determined by placing it in water and measuring the temperature after a period of time.<ref>Hyperphysics, ''Calorimetry'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/calor.html#c1</ref>


[[File:Zeroth.gif|thumb|800px|center|Figure 1. The zeroth law of thermodynamics.<ref>Hyperphysics, ''Zeroth Law of Thermodynamics'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thereq.html#c2</ref>]]  
[[File:Zeroth.gif|thumb|800px|center|Figure 1. The zeroth law of thermodynamics.<ref>Hyperphysics, ''Zeroth Law of Thermodynamics'' [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thereq.html#c2</ref>]]  
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:''[[Earth's energy budget|main article]]''
:''[[Earth's energy budget|main article]]''


It is very important for the Earth to remain in equilibrium in order for its temperature to remain constant. The incoming [[solar energy to the Earth]] must be balanced, meaning the Earth must radiate just as much as [[radiant heat|heat]] it is receiving. The [[temperature of the Earth]] relies on the natural [[greenhouse effect]] in order to be habitable by humans and other animals, and without it the Earth would be [[Earth Temperature without GHGs|far too cold]]. However the increase of [[carbon dioxide]] and [[methane]] in the [[atmosphere]] is increasing this greenhouse effect, causing slightly less heat to be let out of the Earth than is absorbed in [[Earth's energy flows]]. This slight imbalance from equilibrium is leading to a [[global warming|warming climate]].
It is very important for the Earth to remain in thermal equilibrium in order for its temperature to remain constant. The incoming [[solar energy to the Earth]] must be balanced—meaning the Earth must [[radiant heat|radiate just as much as heat]] as it receives. The [[greenhouse effect]] slows down the heat transfer from Earth to space, making the planet hotter. The [[temperature of the Earth]] relies on the natural [[greenhouse effect]] in order to be habitable by humans and other animals and without it, the Earth would be [[Earth Temperature without GHGs|far too cold]]. However, the increase of [[carbon dioxide]], [[methane]] and [[NOx|nitrogen dioxide]] in the [[atmosphere]] is increasing this greenhouse effect, causing slightly less heat to be let out of the Earth than is absorbed in [[Earth's energy flows]]. This slight imbalance from equilibrium is leading to a [[global warming|warming climate]] which is changing the planet in dangerous ways.
 
==For Further Reading==
*[[Zeroth law of thermodynamics]]
*[[Law of conservation of energy]]
*[[Earth's energy budget]]
*[[Equilibrium]]
*[[Greenhouse effect]]
*Or explore a [[Special:Random|random page]]


==References==
==References==
{{reflist}}
{{reflist}}
[[Category:Uploaded]]
[[Category:Uploaded]]

Revision as of 23:55, 8 June 2018

Heat is the flow of energy from a high temperature to a low temperature. When these temperatures balance out, heat stops flowing, then the system (or set of systems) is said to be in thermal equilibrium.[1] The zeroth law of thermodynamics uses thermal equilibrium to define how two different systems can be said to be at the same temperature. For example, when molten rock comes up from a volcano, it will give off heat to the atmosphere until the rock and the atmosphere are at the same temperature. Even though the two systems (rock and air) are very different, thermal equilibrium allows a definition of temperature for both.

All systems tend towards thermal equilibrium over time—and some systems will take a lot longer than others. Knowing that interacting systems will tend towards the same temperature allows for important applications in all areas of science. For example, the specific heat capacity of a substance can be determined by placing it in water and measuring the temperature after a period of time.[2]

Figure 1. The zeroth law of thermodynamics.[3]

Equilibrium of the Earth

main article

It is very important for the Earth to remain in thermal equilibrium in order for its temperature to remain constant. The incoming solar energy to the Earth must be balanced—meaning the Earth must radiate just as much as heat as it receives. The greenhouse effect slows down the heat transfer from Earth to space, making the planet hotter. The temperature of the Earth relies on the natural greenhouse effect in order to be habitable by humans and other animals and without it, the Earth would be far too cold. However, the increase of carbon dioxide, methane and nitrogen dioxide in the atmosphere is increasing this greenhouse effect, causing slightly less heat to be let out of the Earth than is absorbed in Earth's energy flows. This slight imbalance from equilibrium is leading to a warming climate which is changing the planet in dangerous ways.

For Further Reading

References

  1. Hyperphysics, Thermal equilbrium [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thereq.html
  2. Hyperphysics, Calorimetry [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/calor.html#c1
  3. Hyperphysics, Zeroth Law of Thermodynamics [Online], Available: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thereq.html#c2