carnotcycle

The total number of countries visiting CarnotCycle in March 2026 was 94. With 14 years of continuous online presence this blog can fairly claim to have attained global reach. The total number of countries visiting CarnotCycle in March 2026 was 94. With 14 years of continuous online presence this blog can fairly claim to have attained global reach.

The molecular formula for benzoic acid is C7H6O2, so Google AI is being asked to compile the following equation and solve for x 7x + (6 × 1) + (2 × -2) = 0 x = -2/7 Well within Google AI’s capabilities one would think. But when I put this question to Google’s Gemini chatbot on 11 October 2025, it responded in the first instance with -1/3, then corrected it to -3/7, both wrong answers. I asked aga…

Have you ever wondered who pioneered the organizing of physical chemistry into a textbook science? Well, it will come as no surprise to the curious that it was the same people who pioneered the science itself in the late 19th century: principally Wilhelm Ostwald, J.H. van ‘t Hoff and Svante Arrhenius. This Nobel Prize-winning trio were respectively German, Dutch and Swedish, so it set me wonderin…

The drone in the photo is an ST16B. It weighs only 142 grams, has no camera, costs less than 50 dollars and is designed for kids with no drone flying experience to learn the basics. It also provides an inexpensive way to explore atmospheric parameters in the near terrain region up to around 100 feet (30 meters). Here’s a quick guide to exploring near terrain atmospherics in your hood. 1: The dron…

The computer spreadsheet evolved in the 1980s from paper-based bookkeeping and accounting worksheets and has since developed into a highly versatile tool, whether for complex business model canvases or simply recording Cindy and Bob’s widget sales. But apps like Excel can equally well be used for scientific purposes such as simulating the DNA transcription process by which cells synthesize protei…

Every day this blog gets visits from all over the world, and in numbers which show that thermodynamics interests many, many people. They come from lands big and small, rich and poor, happy and less-than-happy. And they are all united in their desire for knowledge. Knowledge is power. And in the case of thermodynamics, that knowledge is especially powerful. Because its subject is energy, which in …

OK so here’s a different way of illustrating the Calvin Cycle, the light-independent sequence of reactions in photosynthesis. There are no molecular representations, no long chemical names. Instead, this cycle shows the number of carbon atoms in the input, output and cycle intermediates, together with their average oxidation states and the number of molecules present. The key at top right is your…

The Liberty Bell 3-reel slot machine, made by Charles August Fey, San Francisco, 1899 In the days of my youth, slot machines were part of the furniture of life. Essential scenery in bars, cafés, arcades, everywhere we chilled out. I have an analytical turn of mind but cannot recall ever applying it to these devices. There is something hypnotic about the spinning reels that causes us to suspend lo…

For most people, sitting on an airplane is just like sitting on a bus or a train. The view from the window might be different, but the air you breathe is the same. Except it isn’t. Cabin air at altitude contains 25% less oxygen than it does at ground level. That’s a sizeable reduction that savvy fliers need to be aware of. Why the reduction? Atmospheric pressure drops as altitude increases. So as…

CarnotCycle is pleased to note that Leonid Alekseevich Molev, a 5th grade student at Lyceum No.8 in Voronezh in southwestern Russia, was awarded a diploma for his Computer Science research project “Arduino platform basement ventilation system” submitted in summer 2022. Using an Arduino nano 328 microcontroller equipped with indoor and outdoor DHT-11 RH&T sensors, Leonid’s system employs the absol…

I have seen the glow of a glowworm on only one occasion. It was many years ago in rural England and I remember wondering at the time whether the worm co-produced heat and light like an incandescent light bulb, and whether the fairly rapid sequence of switching the light off and on again was to […]

It has been reported by international news agencies that tech giant Microsoft has signed a deal to purchase electricity from the currently shut-down nuclear plant at Three Mile Island in Pennsylvania in order to provide non-carbon energy to fuel the expansion of its power-hungry artificial intelligence (AI) data centers. The Three Mile Island plant has […]

De Moivre’s discovery of standard deviation Background Although the term standard deviation as a measure of dispersion is widely associated with the British statistician Karl Pearson (1857- 1936) who coined the term in 1894, this powerful parameter had actually been discovered and put to use well over a century before when it appeared in the 2nd edition of a book entitled The Doctrine of Chances,…

The history of the incandescent electric light bulb goes way back to 1800, when Alessandro Volta invented an early form of battery called the Voltaic pile. This device produced continuous direct current, and it was soon discovered that when passed through conductive materials the current was capable of producing heat and, under certain circumstances, light. […]

Special in every way: 7-sided dice Smarter than the average dice, don’t you think? Just an inch long yet weighing a nicely solid 14 grams, these 7-sided polished bronze stainless steel dice from The Trinket Emporium have a pleasant feel in the hand and roll amazingly well. And while rolling them, one can marvel at the engineering that makes a 7-sided die possible. A rolling die with a regular hep…

Smarter than the average dice, don’t you think? Just an inch long yet weighing a nicely solid 14 grams, these 7-sided polished bronze stainless steel dice from The Trinket Emporium have a pleasant feel in the hand and roll amazingly well. And while rolling them, one can marvel at the engineering that makes a 7-sided […]

The replacement of wood by coal as the world’s main source of energy stoked the engine of the industrial revolution as the world entered the 19th century. It was known that a flammable gas could be obtained from coal by destructive distillation, and it was not long before enterprising individuals thought of using it for […]

Measuring radon levels in indoor spaces needs a device such as the one illustrated which performs continuous monitoring. This is because levels can and do fluctuate considerably. While the short-term figure goes up and down from day to day, and to a lesser extent from week to week (the display shows alternating 1-day and 7-day […]

In January 2020, this blog ran a post about Direct Air Capture (DAC), a somewhat misleading term that came into use for processes designed to extract carbon dioxide directly from the atmosphere. Three years later, DAC is one of an array of technologies under the general banner of Carbon Dioxide Removal (CDR), which I gather […]

Ever since the works of J. Willard Gibbs were first published, people have struggled to understand him. Back in 1892 Lord Rayleigh, by all accounts a capable physicist and mathematician, complained to Gibbs that his masterwork On the Equilibrium of Heterogeneous Substances was “too condensed and too difficult for most, I might say all, readers”. […]