What is Energy in Thermodynamics ?

In summary, the conversation discusses the concept of energy and its intangible nature. It is described as a quantity that is preserved or transferred during a process and is measured using thermodynamics. The speakers also touch upon the understanding of energy as a cause rather than a tangible entity and its effect on observable quantities. The conversation ends with a suggestion to research existing threads on the topic before proceeding further.
  • #1
Harisankar
7
0
Using Thermodynamics we can measure a certain quantity that is preserved/transferred during a process and we call it energy.
We feel it's existence based on it's effect on other observable quantities(say motion for instance) and we do not "know" energy as itself.Am I right?

So do we energy only as a cause and never as itself?
 
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  • #2
i think we can define it like that under some lmitations
 
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  • #3
Your first statement is pretty much saying that energy is intangible, which is true.

So do we energy only as a cause and never as itself?

However, I don't understand the above. Can you please clarify?
 
  • #4
hubewa said:
Your first statement is pretty much saying that energy is intangible, which is true.



However, I don't understand the above. Can you please clarify?

I am really sorry.
I meant to say,"Do we feel energy only as a cause and never as itself?".

Let's say,we feel the effect of heat energy,temperature,we don't feel heat energy itself now,do we?
 
  • #5
Let's say,we feel the effect of heat energy,temperature,we don't feel heat energy itself now,do we?

Not a correct assumption.

When we feel the effect of heat energy, energy is still intangible. No matter how much we want to, it will never become tangible as you seem to suggest so it's impossible to say something like "heat energy itself".

If we do feel the effect of heat energy, well, then we feel the effect of heat energy.

we do not "know" energy as itself

I think that, itself, would be a reasonable analysis. This, rather, is due to the fact is because energy is intangible. You cannot pick up 5J of energy here and there.

If there is something extra that I don't understand, can you please clarify? Thanks.
 
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  • #6
Harisankar said:
We feel it's existence based on it's effect on other observable quantities(say motion for instance) and we do not "know" energy as itself.Am I right?
No. Making observations and connecting them to each other with math is what physics is about. So that's all that energy is!
 
  • #7
Thank you Aravind,Hubewa and Russ.
You have given me more insight not only to my question but also to the presentation of a question.
So the bottom line is energy is an inherent entity in the universe and it's presence is ascertained only by it's effect on measurable parameters.
 
  • #8
Harisankar said:
We feel it's existence based on it's effect on other observable quantities(say motion for instance) and we do not "know" energy as itself.Am I right?
Before you go too far you may want to read other threads by the same name:

https://www.physicsforums.com/showthread.php?t=507345
https://www.physicsforums.com/showthread.php?t=498497

These have both been within the last couple of months, both threads were locked, and both resulted in the ban of one or more of the participants. By going through the existing threads you can probably find the information you need without risking getting banned yourself.
 
  • #9

Related to What is Energy in Thermodynamics ?

1. What is energy in thermodynamics?

Energy in thermodynamics is the ability of a system to do work or produce heat. It is a fundamental concept in thermodynamics and is closely related to the first law of thermodynamics, which states that energy cannot be created or destroyed, only transferred or converted from one form to another.

2. How is energy related to thermodynamics?

Energy is a key concept in thermodynamics as it is used to describe the behavior of systems that involve heat and work. In thermodynamics, energy can be classified into two types: internal energy and external energy. Internal energy refers to the total energy of a system, including the kinetic and potential energy of its particles. External energy, on the other hand, is the energy transferred to or from a system as heat or work.

3. What are the forms of energy in thermodynamics?

In thermodynamics, energy can exist in various forms, including thermal energy, mechanical energy, electrical energy, chemical energy, and nuclear energy. These forms of energy can be converted from one to another through various thermodynamic processes such as heating, compression, and expansion.

4. How is energy measured in thermodynamics?

In thermodynamics, energy is typically measured in joules (J) or calories (cal). Joules are the standard unit of energy in the International System of Units (SI), while calories are commonly used in the field of thermodynamics. Additionally, energy can also be measured in other units such as BTUs (British Thermal Units) and kilowatt-hours (kWh).

5. How does thermodynamics relate to energy conservation?

Thermodynamics is based on the principle of energy conservation, which states that the total energy of an isolated system remains constant over time. This means that energy cannot be created or destroyed, only transferred or converted from one form to another. In thermodynamics, energy conservation is expressed through the first law of thermodynamics, which is also known as the law of conservation of energy.

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