Hello! Thank you for stopping by to read about the Second Law of Thermodynamics.
Why you should understand the Second Law of Thermodynamics: The second law of thermodynamics is responsible for many important changes that we observe in our world. So yeah, it's important.
Key Ideas
- Defining the Second Law of Thermodynamics
- What it means in real life
- Examples
Defining the Second Law of Thermodynamics
The Second Law of Thermodynamics states that entropy always increases. In other words, everything in a system tends toward disorder. However, Entropy is better described using terms of probability.
An increase in microstates (which are the individual states or "snapshots" of a system) describes an increase in entropy. Therefore, the second law of thermodynamics states that the number of microstates within a system is constantly increasing. If the concept of microstates is confusing, I've described the idea in more detail in my entropy post which I've linked above.
What it means in real life
In real life, the second law of thermodynamics applies to many different theories and scenarios. I'm not a physical chemist, so the idea that the second law of thermodynamics is responsible for evolution or the age of the planet is a little over my head. However, these topics are very interesting and are described in this article: https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Thermodynamics/The_Four_Laws_of_Thermodynamics/Second_Law_of_Thermodynamics
Examples
So let's look at some simple examples of the second law of thermodynamics.
Ice melting: I'll probably always come back to this example. Ice melting is an example of the second law because the ice is going from a solid which is more ordered to a liquid which is more disordered.
Laundry in the Dryer: When you put laundry in the dryer, you place the clothes in a certain way. As the laundry tumbles around, they are constantly changing location, temperature, and even how they are folded. As a result, the entropy increases when clothes are tumbled around in the dryer.
The organization of a bedroom: I don't know about you but my bedroom never seems to stay clean and the second law of thermodynamics is the reason why (not because I'm a messy person, mom). A room or a closet will always tend towards disorder because entropy is always increasing. So tell your mom that your room is messy because of thermodynamics, I'm sure she'll appreciate it.
Summary
- The Second Law of Thermodynamics states that entropy always increases.
- An increase in microstates describes an increase in entropy. Therefore, the second law of thermodynamics states that the number of microstates within a system is constantly increasing.
I hope that you've found this post about the Second Law of Thermodynamics helpful. If you have any questions feel free to comment on this post, message me, or comment on my youtube video that I've linked below.
- Saren
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