Bob’s Posts

Career decision making – trust your gut

When I give thermodynamics presentations to high school and college students, I begin with a 10-minute discussion about career decision-making based on my own experiences. I now share this discussion with you, both to provide you with helpful and hopefully inspiring ideas and to also seek your feedback. Do your thoughts align with mine? Let…

Why I paid $100 for a Vonnegut quote

Publisher: “Before we go to print, we just wanted to make sure you got permissions for the epigraphs in your book.” Me: “What’s an epigraph?” As I was traveling through the final stages of publishing my book, I learned that there are two approaches to using a quote. One is to embed the quote in…

Newton: On whose shoulders did he stand?

No Newton, no Principia. That much is clear. But did Newton do it alone? He was naturally exposed to the ideas of such predecessors as Descartes and Galileo and such contemporaries as Leibniz and Huygens. That this collective influenced Newton is reflected in his own writing, “If I have seen further it is by standing…

How did Galileo measure time?

Galileo, perhaps more than any other single person, was responsible for the birth of modern science – Steven Hawking [1] Galileo was fascinated by motion and continually experimented with pendulums, cannons, and rolling balls to understand why bodies move the way they do. The arguable culmination of these efforts occurred in 1604 when he discovered…

Science and the power of multiple hypotheses

When asked my opinion on various science-related topics that are in the news, my usual reply is, “I don’t know.” It’s not that I’m incapable of knowing. It’s that I haven’t studied the topics in enough detail to have a well-grounded opinion. My scientific expertise lays elsewhere, in a less popular news cycle. HOWEVER If…

Joule-Thomson Effect (Part 2) – my hypothesis

In a previous video (here), I stated my belief that a better understanding of thermodynamics is available by identifying the connections between the micro-world of moving and interacting atoms and the macro-world of classical thermodynamics. My goal is to do just this. My starting point? The Joule-Thomson effect, which is the temperature change that occurs…

Goggins, Full Capability, and “Atoms First” Thermodynamics

David Goggins, ex-Navy SEAL, now ultra-athlete and motivational speaker, shared in a popular YouTube video (JRE #1212) something that I found incredibly motivating. His biggest fear, and I paraphrase here, is that he arrives at the gates of Heaven and sees God there with a clipboard, holding a list of many great accomplishments. Goggins’ fear…

Thermodynamic “pain point” results – here are your responses

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,…

What are your personal “pain points” with thermodynamics?

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 in…

The Road to Entropy – Boltzmann and his probabilistic entropy

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. Loschmidt…

The Road to Entropy – The kinetic theory of gases & heat capacity

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, and…

The Road to Entropy – Clausius, Gibbs, and increasing entropy

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 me…

The Road to Entropy – Clausius undaunted

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 moving…

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 a…

Riddle me this: why does dS = 0 for reversible, adiabatic expansion?

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, I…

Thermodynamics: What is “heat”? (video)

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.

Riddle me this: what is the physical significance of T∆S in Gibbs’ maximum work equation?

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 reasonable…

Like a Bird – Flying Balloons on Other Planets

* * * 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 reasons…

Riddle me this: why does a gas deviate from ideal behavior?

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.  He…

Why Do Balloons Float?

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 Thin…

How to conduct powerful science? Check your ego at the door.

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…

Carrying the Dreams of the Montgolfier Brothers to Other Worlds

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-Caltech…

Electric Cars – Is “zero emissions” a valid claim?

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 for…

Happy birthday, Henrietta Leavitt!

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.…

Here’s Why I Wrote “Block by Block” (video)

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!

About Me

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.

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