Entropy Question

[tylers100]

Some words associated with the entropy definition as looked up:

• disorder
• randomness
• uncertainty
• energy dispersal

I know that the consequence of entropy is irreversible, but which one of these associated words fit the entropy definition best?

[exchemist]

3 hours ago, tylers100 said:

Some words associated with the entropy definition as looked up:

• disorder
• randomness
• uncertainty
• energy dispersal

I know that the consequence of entropy is irreversible, but which one of these associated words fit the entropy definition best?

Looks like a homework multiple choice question.

What do you think and what makes you uncertain of the best answer?

[tylers100]

31 minutes ago, exchemist said:

Looks like a homework multiple choice question.

What do you think and what makes you uncertain of the best answer?

I think that the energy dispersal seems to be best answer. It reminds me of decay / decomposition, one of seemingly naturally-occurred states of living things that undergo after death. I wasn't sure because entropy and these first words / meanings (disorder, randomness, uncertainty) as impressed upon me is that scientists still don't understand it so that cause me to be not sure as well at first place.

[studiot]

1 hour ago, tylers100 said:

I think that the energy dispersal seems to be best answer. It reminds me of decay / decomposition, one of seemingly naturally-occurred states of living things that undergo after death. I wasn't sure because entropy and these first words / meanings (disorder, randomness, uncertainty) as impressed upon me is that scientists still don't understand it so that cause me to be not sure as well at first place.

Well done, I agree. +1

One way to think of this is to look at the units of each quantity.

Entropy has units of energy transfer divided by temperature.

Disorder and randomness are pure numbers ie they do not have units.

Uncertainty has no particular units of its own and always needs a complement ie ( 'something has to be uncertain' ) and takes on the units of the complement.
The victim was murdered between 10 pm and midnight give an uncertainty of 2 hours for instance.

So you are left with energy decay which has units of energy transfer divided by time, which would be the nearest.

[exchemist]

3 hours ago, tylers100 said:

I think that the energy dispersal seems to be best answer. It reminds me of decay / decomposition, one of seemingly naturally-occurred states of living things that undergo after death. I wasn't sure because entropy and these first words / meanings (disorder, randomness, uncertainty) as impressed upon me is that scientists still don't understand it so that cause me to be not sure as well at first place.

Yep, that's the one I would go for as well, for the same reasons as @studiot. As the units of entropy are energy/temperature, say J/K, it gives a sense of thermal energy becoming less able to do work as its temperature drops, so a sort of heat dissipation.

It's a bit harder to see how this applies in the case of entropy of mixing, but in that case too each component it becomes spread out through a larger volume, so its internal energy becomes more dissipated.  

[swansont]

3 hours ago, tylers100 said:

these first words / meanings (disorder, randomness, uncertainty) as impressed upon me is that scientists still don't understand it so that cause me to be not sure as well at first place.

Perhaps it's more that entropy defies an easy distillation into a sound bite. To say that scientists don't understand it is true in the same sense that we still have more to discover, as with all science, but not so much in the sense that we have no understanding of it.

Feynman had a good quote about this difficulty, when someone asked about magnets in an interview

I really can’t do a good job, any job, of explaining magnetic force in terms of something else you’re more familiar with, because I don’t understand it in terms of anything else you’re more familiar with.

IOW, there are some situations in physics where you need to learn some physics in order to develop an understanding of a concept.

[tylers100]

An Additional Question

Is energy dispersal a bunch of "mismatched" puzzles leftover?

I asked this question because of the jigsaw puzzles analogy I have on my mind regarding the entropy gist.

Jigsaw Puzzles Analogy

I presume some of us are familiar with the jigsaw puzzles. The rule is we simply put it together correctly to form a complete picture of something.

What would happen if we force putting mismatched jigsaw puzzles together? Of course, we would get mismatch or incomplete picture of something.

What if mismatched jigsaw puzzles are entropy?

[studiot]

6 hours ago, tylers100 said:

An Additional Question

Is energy dispersal a bunch of "mismatched" puzzles leftover?

I asked this question because of the jigsaw puzzles analogy I have on my mind regarding the entropy gist.

Jigsaw Puzzles Analogy

I presume some of us are familiar with the jigsaw puzzles. The rule is we simply put it together correctly to form a complete picture of something.

What would happen if we force putting mismatched jigsaw puzzles together? Of course, we would get mismatch or incomplete picture of something.

What if mismatched jigsaw puzzles are entropy?

Enntropy is not about 'things left over'.

The important word in your phrase energy dispersal is not energy but dispersal.

Note the difference between dispersal and dissipation.

Dispersal means spreading out, and becoming less concentrated, it does not imply disappearing.

Dissipation implies disappearing or weakening.

 

A good analogy to think about is a lump of sugar added to your coffee.

When you first add the sugar there is a large quantity in one small part of the cup and little or nothing in the rest.

As you stir, the sugar spreads out over the entire volume of coffee, becoming evenly concentrated everywhere.

This spreading out or evening out is driven by entropy.

But we do not measure entropy in lumps of sugar, we measure it in terms of energy because energy is a property common to many different spreading out processes.