The entropy of systems

Jim,

I found this text at : www.people.cornell.edu/pages/jag8/index.html

"Thermal or "work" entropy, as generally defined, is the energy in an isolated system which on principle cannot be transformed to work. Entropy characterizes the degradation of energy inherent in the operation of any engine or process of energy transformation, typically manifest as "heat loss": the same energy cannot be used twice to produce the same net work. These ideas imply the conservation of energy and the impossibility of a perpetual motion machine. Entropy is a principle safeguarding energy conservation, allowing the transformation of energy. Entropy prevents the abuse of energy; <b>without the principle of entropy, energy conservation would prevent any use or transformation of energy at all</b>.".....

....."So essential is the connection between entropy and energy conservation that entropy is an embedded physical characteristic of energy ...."


GD:

-In order for energy to do work, the presence of symmetry breaking (gravity) and knowing that entropy is an embedded physical characteristic of energy, how do you explain a universe which is in equilibrium ?

Hi GD, I can't explain the universe-can't even explain tiny parts of the universe. I try to keep an open mind though and so far nothing I learn helps to explain or understand how things work. I know entropy works very well when heat processes are considered but heat requires both energy and matter whereas energy works without any matter being involved and the thermal rules don't work when energy only processes are being considered. Look at a common light bulb for example, it gives heat and light. The LED using the same energy gives much more light but if you use thermal rules the LED can be shown to be radiating maybe a thousand times as much energy. The rules fail when pushed beyond their limits. Light data from stars is mismanaged in this way too. Anyay, entrophy is a very useful tool-the best(IMO) definition is its a relationship of molecules within a system.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jim</i>
<br />... whereas energy works without any matter being involved...<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Hello jim,

The energy (example: light) comes from the entropy (energy transfer) from matter.

Light is impossible without matter.

Light alone is impossible. Something happens to matter to cause light.

The evolution of a hydrogen cloud into a sun is an example of this.
Forces caused by energy transfer within the atom in a mass causes work (motion) + heat. The result of this work is light.
This is the same idea with a light bulb.
Light is not hot, it is the atoms doing the work that are hot.

Do you see this?

GD, Yea, I see this. In the LED the amount of heat is very small compared to incandesant bulb-I'm sure you see this. The bulb's heat or infrared can be estimated using blackbody law but the light is not heat so its not included in the blackbody estimate-you may not agree. The LED is 95% light and if the blackbody law is used it will show heat energy that is not there and a temperature near the blackbody temp of the sun which clearly is the wrong answer. Its a common practice to use blackbody law to estimate star power. Well I guess this a different topic and off the subject but its one of the dots that makeup the total subject of how we misuse data and get the wrong result. You are right about life being part of the universe don't know what promped that observation.

Jim,

I don't understand the point you are trying to make?

Here is the blackbody definition:

"In physics, a black body is an object that absorbs all electromagnetic radiation that falls on it. No electromagnetic radiation passes through it and none is reflected. Because no light (visible electromagnetic radiation) is reflected or transmitted, the object appears black when it is cold.

If the black body is hot, these properties make it an ideal source of thermal radiation."

The sun would fall under the second black body definition: ...If the black body is hot...


The sun radiates in the visible range of frequencies or else we would not see it...


Where is the source of power for the LED's? This is where you will find the heat...

Jim,

Where does light come from?