Bob’s Posts

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

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 reasonsContinue reading “Like a Bird – Flying Balloons on Other Planets”

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.  HeContinue reading “Riddle me this: why does a gas deviate from ideal behavior?”

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 ThinContinue reading “Why Do Balloons Float?”

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 differing perspectives is encouraged in order to learn and not to win.

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-CaltechContinue reading “Carrying the Dreams of the Montgolfier Brothers to Other Worlds”

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

The 170th Anniversary of the 1st Law of Thermodynamics — A Tribute to Rudolf Clausius

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”

Here’s Why I Wrote “Block by Block”

I’m very excited to share in this 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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