Thermodynamic entropy | Asymmetry
Entropy is one of the few quantities in the physical sciences that require a particular direction for time, sometimes called an arrow of time. As one goes "forward" in time, the second law of thermodynamics says, the entropy of an isolated system can increase, but not decrease. Thus, entropy measurement is a way of distinguishing the past from the future. In thermodynamic systems that are not isolated, entropy can decrease with time, for example living systems where local entropy is reduced at the expense of an environmental increase (resulting in a net increase in entropy), the formation of typical crystals, the workings of a refrigerator and within living organisms. Much like temperature, despite being an abstract concept, everyone has an intuitive sense of the effects of entropy. For example, it is often very easy to tell the difference between a video being played forwards or backwards. A video may depict a wood fire that melts a nearby ice block, played in reverse it would show that a puddle of water turned a cloud of smoke into unburnt wood and froze itself in the process. Surprisingly, in either case the vast majority of the laws of physics are not broken by these processes, a notable exception being the second law of thermodynamics. When a law of physics applies equally when time is reversed, it is said to show T-symmetry; in this case, entropy is what allows one to decide if the video described above is playing forwards or in reverse as intuitively we identify that only when played forwards the entropy of the scene is increasing. Because of the second law of thermodynamics, entropy prevents macroscopic processes showing T-symmetry. When studying at a microscopic scale, the above judgements cannot be made. Watching a single smoke particle buffeted by air, it would not be clear if a video was playing forwards or in reverse, and, in fact, it would not be possible as the laws which apply show T-symmetry. As it drifts left or right, qualitatively it looks no different. It is only when the gas is studied at a macroscopic scale that the effects of entropy become noticeable. On average it would be expected that the smoke particles around a struck match would drift away from each other, diffusing throughout the available space. It would be an astronomically improbable event for all the particles to cluster together, yet the movement of any one smoke particle cannot be predicted. By contrast, certain subatomic interactions involving the weak nuclear force violate the conservation of parity, but only very rarely. According to the CPT theorem, this means they should also be time irreversible, and so establish an arrow of time. This, however, is neither linked to the thermodynamic arrow of time, nor has anything to do with the daily experience of time irreversibility. Unsolved problem in physics: Arrow of time: Why did the universe have such low entropy in the past, resulting in the distinction between past and future and the second law of thermodynamics? (more unsolved problems in physics) (Wikipedia).
What is entropy? In what fields is it useful? And how does it explain the direction in which transformations occur? All these answers in 12 minutes! 0:00 - Introduction 1:30 - Entropy in physics 4:31 - Entropy in other fields 6:25 - The arrow of Time 10:47 - Conclusion This video is narr
From playlist Matter and Energy
Teach Astronomy - Entropy of the Universe
http://www.teachastronomy.com/ The entropy of the universe is a measure of its disorder or chaos. If the laws of thermodynamics apply to the universe as a whole as they do to individual objects or systems within the universe, then the fate of the universe must be to increase in entropy.
From playlist 23. The Big Bang, Inflation, and General Cosmology 2
Teach Astronomy - The Arrow of Time
http://www.teachastronomy.com/ There may be a profound connection between entropy in the universe and the arrow of time, the pervasive since that time moves only in one direction. Remember that the microscopic laws of physics have no arrow of time. However, in any statistical system of p
From playlist 23. The Big Bang, Inflation, and General Cosmology 2
Entropy: The Heat Death of The Universe
Entropy: The Heat Death of The Universe - https://aperture.gg/heatdeath Sign up with Brilliant for FREE and start learning today: https://brilliant.org/aperture "Maximum Entropy" Hoodies — Available Now: https://aperture.gg/entropy As the arrow of time pushes us forward, each day the univ
From playlist Science & Technology 🚀
Physics - Thermodynamics 2: Ch 32.7 Thermo Potential (10 of 25) What is Entropy?
Visit http://ilectureonline.com for more math and science lectures! In this video explain and give examples of what is entropy. 1) entropy is a measure of the amount of disorder (randomness) of a system. 2) entropy is a measure of thermodynamic equilibrium. Low entropy implies heat flow t
From playlist PHYSICS 32.7 THERMODYNAMIC POTENTIALS
Entropy Explained In 60 Seconds!! #Thermodynamics #Chemistry #Physics #Math #NicholasGKK #Shorts
From playlist Heat and Chemistry
As we experience it, time flows in a single direction. But entropy, and its description in the second law of thermodynamics, is one of the few physical phenomena to imply an actual arrow of time. Day 16 of our advent calendar: http://www.rigb.org/christmas-lectures/supercharged-fuelling-th
From playlist The four laws of thermodynamics
The Misunderstood Nature of Entropy
Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here: https://to.pbs.org/DonateSPACE Entropy and the second law of thermodynamics has been credited with defining the arrow of time. You can further support us on Patreon at https://www.patreon.com/pbssp
From playlist Space Time!
A better description of entropy
I use this stirling engine to explain entropy. Entropy is normally described as a measure of disorder but I don't think that's helpful. Here's a better description. Visit my blog here: http://stevemould.com Follow me on twitter here: http://twitter.com/moulds Buy nerdy maths things here:
From playlist Best of
Innovation Speaker Series - Sean Carroll - 7/6/17
Sean Carroll, Research Professor of Physics, Caltech From Sean Carroll: "I'm a theoretical physicist at Caltech in sunny Pasadena, California. I do research on theoretical aspects of cosmology, field theory, gravitation, and quantum mechanics. I want to learn about fundamental physics by
From playlist Innovation Speaker Series - Summer App Space 2017
Why Did Time Start Going Forward?
Researched and Written by Leila Battison Narrated and Edited by David Kelly Thumbnail Art by Ettore Mazza If you like our videos, check out Leila's Youtube channel: https://www.youtube.com/channel/UCXIk7euOGq6jkptjTzEz5kQ Music from Silver Maple, Epidemic Sound and Artlist. Stock foota
From playlist The Entire History of the Universe
Why Do You Remember The Past But Not The Future?
PBS Member Stations rely on viewers like you. To support your local station, go to: http://to.pbs.org/DonateSPACE ↓ More info below ↓ Sign Up on Patreon to get access to the Space Time Discord! https://www.patreon.com/pbsspacetime The laws of physics don’t specify an arrow of time - the
From playlist Entropy Explained!
The mind-bending physics of time | Sean Carroll
How the Big Bang gave us time, explained by theoretical physicist Sean Carroll. Subscribe to Big Think on YouTube ► https://www.youtube.com/channel/UCvQECJukTDE2i6aCoMnS-Vg?sub_confirmation=1 Up next, The Universe in 90 minutes: Time, free will, God, & more ► https://youtu.be/tM4sLmt1Ui8
From playlist Space & physics
What is Time? - The Arrow of Time Explained Learn more about the topics I covered in this video for FREE over at https://brilliant.org/aperture Join the community Discord!: https://discord.gg/XjSEXMS This video was made in collaboration with Questn. Questn: https://www.youtube.com/cha
From playlist Science & Technology 🚀
Mysterious numbers: unlocking the secrets of the Universe - with Tony Padilla
Join leading theoretical physicist and YouTube star Tony Padilla as he explores the most extraordinary numbers in physics, and how they explain fundamental truths of the universe. Watch the Q&A here: https://youtu.be/dhT_vl3epgY Tony's book "Fantastic Numbers and Where to Find Them: A Cos
From playlist Mathematics
Why does time go forward? How does Entropy relate to the direction of time? What really is time, and what gives it a direction? The Arrow of Time. Hi! I'm Jade. I draw pictures that move and become animated physics videos. ***SUBSCRIBE*** https://www.youtube.com/c/upandatom ***Let's b
From playlist Physics
Why Doesn't Time Flow Backwards? (Big Picture Ep. 1/5)
Thanks to Google Making and Science for supporting this series, and to Sean Carroll for collaborating on it! His book can be found here: http://www.penguinrandomhouse.com/books/316646/the-big-picture-by-sean-carroll/ Playlist of the full video series: https://www.youtube.com/playlist?list
From playlist The Big Picture (Time & Entropy, feat. Sean Carroll)
Topics in Combinatorics lecture 10.0 --- The formula for entropy
In this video I present the formula for the entropy of a random variable that takes values in a finite set, prove that it satisfies the entropy axioms, and prove that it is the only formula that satisfies the entropy axioms. 0:00 The formula for entropy and proof that it satisfies the ax
From playlist Topics in Combinatorics (Cambridge Part III course)