Author Archives: Robert T Hanlon

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 – The Newcomen and Watt “Steam” Engines (videos)

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)”

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, IContinue reading “Riddle me this: why does dS = 0 for reversible, adiabatic expansion?”

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

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?”

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.

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?”

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.Continue reading “Happy birthday, Henrietta Leavitt!”