I believe that a better understanding of thermodynamics is available by explaining the connections between the micro-world of moving and colliding atoms that attract and repel each other and the macro-world of classical thermodynamics. My goal is to identify and clarify such micro-to-macro connections. To ensure that I’m addressing true needs of the science community,Continue reading “Thermodynamic “pain point” results – here are your responses”
What are your personal “pain points” with thermodynamics? What are the stumbling blocks you encounter when trying to understand the physical meaning behind such thermodynamic equations and phenomena as Gibbs Free Energy, Joule-Thomson expansion, phase change, and even the physical properties of matter, including heat capacity and absolute temperature? Could you please share these with me inContinue reading “What are your personal “pain points” with thermodynamics?”
Ludwig Boltzmann (1844-1906) brought his mastery of mathematics to the kinetic theory of gases and provided us with our first mechanical understanding of entropy. To Boltzmann, his work proved that entropy ALWAYS increases or remains constant. But to others, most notably Josef Loschmidt (1821-1895), his work contained a paradox that needed to be addressed. LoschmidtContinue reading “The Road to Entropy – Boltzmann and his probabilistic entropy”
I believe that an improved approach to teaching thermodynamics can be created by starting with the atomic theory of matter and then explaining the connections between this theory and macroscopic thermodynamic phenomena. This micro-to-macro approach arguably began in the late 19th century when a small group of scientists, namely Rudolf Clausius, James Clerk Maxwell, andContinue reading “The Road to Entropy – The kinetic theory of gases & heat capacity”
At the conclusion of his famed 1865 paper announcing the discovery of a new property of matter that he named entropy, Rudolf Clausius stated: the entropy of the universe tends to a maximum. This statement came as a total surprise to me as there was no prior supportive discussion behind it, and it had meContinue reading “The Road to Entropy – Clausius, Gibbs, and increasing entropy”
Have you ever experienced that wondrous “Eureka!” moment of insight when you’ve discovered some hidden secret of nature? Archimedes did when he realized that the volume of water displaced is equal to the volume of the body submerged. Kekulé did when discovered benzene’s structure. Hubble did when he discovered that the stars are all movingContinue reading “The Road to Entropy – Clausius undaunted”
James Joule could have observed what he did and then done nothing with it. Instead, he became driven to understand and explain it and so discovered the mechanical equivalent of heat, a forerunner of the concept of energy and the 1st law of Thermodynamics. His story is a good one, an inspiring one, an exampleContinue reading “The Road to Entropy – James Joule and the power of his curiosity (video)”
The commercialization of the high-pressure steam engines by the Cornish Engineers of Britain inspired Sadi Carnot, a French military engineer, to analyze these engines and seek the theories to guide their improvement. If you’re interested in doing a deep dive into Sadi Carnot’s work, here are two excellent references. I go into much more depthContinue reading “The Road to Entropy – Sadi Carnot’s use of analogy to create his “flawed” masterpiece (video)”
I was traveling in Michigan this past week and took a day to visit the Henry Ford Museum of Innovation. All I can say is, WOW! Together with the adjacent Greenfield Village, well worth the visit. The Innovation Museum offers great displays of engine technologies, including the oldest surviving steam engine in the world, aContinue reading “The oldest surviving steam engine is on display at the Henry Ford Museum of Innovation in Michigan”
The Road to Entropy – Phil Hosken on Richard Trevithick and the invention of the high-pressure steam engine (video)
As shared in my previous post (here), the historical road to entropy started with Denis Papin’s development of the piston-in-cylinder assembly and Thomas Newcomen’s and James Watt’s subsequent efforts to commercialize and continuously improve fire engines or atmospheric engines built around this assembly. Steam at atmospheric pressure was employed in these engines, not as aContinue reading “The Road to Entropy – Phil Hosken on Richard Trevithick and the invention of the high-pressure steam engine (video)”
The road to entropy began with the 18th century development of the “steam” engine by Thomas Newcomen and James Watt. But steam was not the driving force in these engines. So what was? And what was the purpose of the steam? Check out this video for the answers: Note the shout-out in the video toContinue reading “The Road to Entropy – The Newcomen and Watt “Steam” Engines (videos)”
While attending an event in Syracuse, New York, I got to talking with an older chemical engineer who had once worked with my dad at Bristol-Myers Laboratories. I shared that I was writing a book on thermodynamics and we spoke some about this. At the conclusion, he looked at me and said, “You know, IContinue reading “Riddle me this: why does dS = 0 for reversible, adiabatic expansion?”
The word “heat” can be very confusing to those trying to learn and understand thermodynamics. I created the below video to help clarify things. I go into more detail about this topic and many others in my book Block by Block – The Historical and Theoretical Foundations of Thermodynamics.
Remember this? Maximum work = -∆Grxn = -(∆Hrxn – T∆Srxn) At some point toward the end of undergraduate thermodynamics, we were taught this equation. Unfortunately, most of us, myself included, graduated without actually understanding it. Why? You already know the answer, just by looking at it. Because entropy is involved. While many have a reasonableContinue reading “Riddle me this: what is the physical significance of T∆S in Gibbs’ maximum work equation?”
* * * For this post I invited back fellow thermodynamics enthusiast Mike Pauken, principal engineer at NASA’s Jet Propulsion Laboratory and author of Thermodynamics for Dummies, to complete this 3-part series related to his work on developing balloons for Venus. His first post covered the developmental history of balloons while his second dove into the fundamental reasonsContinue reading “Like a Bird – Flying Balloons on Other Planets”
Years ago, during on-campus interview season at college, a friend of mine majoring in electrical engineering told of how difficult one of his interviews was. “The interviewer asked me how an oscilloscope worked, and I carefully explained how to plug in the different wires and then how to adjust the knobs and so on. HeContinue reading “Riddle me this: why does a gas deviate from ideal behavior?”
An experimental balloon takes its inaugural flight in August 2020. This particular balloon can change altitude by shortening or lengthening a cord attached the top and bottom of the balloon. Shortening the cord compresses the balloon which makes it descend while lengthening the cord expands the balloon allowing it to ascend. Photo courtesy of ThinContinue reading “Why Do Balloons Float?”
Observe nature, take measurements, and then propose as many hypotheses as you possibly can that are consistent with the data. In this way, you shift the focus from a negative conflict between scientists, each embracing their own individual hypothesis, to a positive, exciting, and team-based conflict between ideas in which technical debate among those with differing perspectives is encouraged in order to learn and not to win.
Balloons – Early Thermodynamics Machines A team of JPL engineers tests whether a large balloon can measure earthquakes from the air. The team proposes to measure “Venus-quakes” from the upper atmosphere of Venus, using an armada of balloons. The author is on the left holding a fan to inflate the solar balloon. Image Credit: NASA/JPL-CaltechContinue reading “Carrying the Dreams of the Montgolfier Brothers to Other Worlds”
I just read an article about an electric vehicle having zero CO2 emissions and thought it’d be an opportune moment to emphasize the value of thermodynamics in critically assessing such claims. Let’s walk through how this is done, starting first with a recap of the foundational mass & energy conservation laws. The conservation laws forContinue reading “Electric Cars – Is “zero emissions” a valid claim?”
You’ve likely heard of the Big Bang theory and the name of Edwin Hubble associated with it. But a person you may not have heard of is Henrietta Leavitt. Leavitt played a critical role in enabling Hubble’s accomplishment. Seeing as today’s her birthday, let’s celebrate her, her achievement, and her impact on astronomy and cosmology.Continue reading “Happy birthday, Henrietta Leavitt!”
More information available here. Or buy now from Oxford University Press or Amazon!
Upon publishing my book, Block by Block – The Historical and Theoretical Foundations of Thermodynamics, Oxford University Press kindly invited me to write a post related to my book for their academic blog. I gladly accepted and chose as my topic the creation of the 1st Law of Thermodynamics by Rudolf Clausius’ work of 1850.Continue reading “The 170th Anniversary of the 1st Law of Thermodynamics — A Tribute to Rudolf Clausius”
I’m very excited to share in the below video why I wrote Block by Block – The Historical and Theoretical Foundations of Thermodynamics. As you’ll see, I clarify my motivation and also the book’s structure. It’s a readable account of both the history and science of thermodynamics. Enjoy!
Hi! I’m Bob Hanlon. After earning my my Sc.D. in chemical engineering from the Massachusetts Institute of Technology and enjoying a long career in both industry and academia, I’ve returned to school, my own self-guided school, seeking to better understand the world of thermodynamics. Please join me on my journey.
Subscribe to My Blog
Get new content delivered directly to your inbox.