Rereading Feynman’s autobiography, this time in English, and my eyes stuck on the word carboy. It turns out that it’s the same as lady jeanne, and the same as demijohn – essentially lady jeanne in French (dame joanne). In short, it’s just a bottle.
Tag: Physics
Aluminum: From Precious Metal to Everyday Marvel | August 03 2025, 01:09
The USA imports aluminum mainly from Canada because aluminum leaves Canada and arrives in the USA. And from Europe, it would be alumin𝒊um!
Also, sapphires and rubies are essentially rusty aluminum, where in the process the new material becomes much harder than the original. In interaction with oxygen, different varieties of the mineral corundum are formed, which chemically is crystalline aluminum oxide (formula Al₂O₃). And bulletproof glass is essentially transparent rusty aluminum, aluminum oxide, but with aluminum nitride.
Also, aluminum was the most valuable metal on Earth until the 20th century. When Napoleon III entertained guests, they ate with golden spoons, while he used an aluminum one. And the “cap” of our Washington Monument is made of aluminum for that very reason.
Time Bending Flights: Greeting Seattle a Quintillionth of a Second Younger | July 19 2025, 05:19
It’s funny to stare at a sentence in a book that says when you fly to the other end of the USA, you become younger than everyone else by a quintillionth of a second — at the moment when you’re sitting on the plane flying to the other end of the USA.
Hello, Seattle!
Why Don’t We Have Self-Sustaining Solar-Powered Drones Yet? | July 16 2025, 01:33
I wonder why we still don’t see autonomous drones that could lead an “eternal” life: landing on roofs, deploying solar panels, charging from the sun, and taking off once a day for whatever their mission might be? When you consider the energy aspects, it seems like a feasible scheme. For instance, a heavy drone weighing about 8 kg could carry foldable solar panels with an area of 1.5 m² and a battery with a capacity of 2 kWh. In one sunny day, such panels could collect about 1.2 kWh of energy — enough for it to fly for 20 minutes at a speed of 40–50 km/h, take photos, and transmit them via the mobile network. And there would still be a reserve of energy for several cloudy days.
Even a light drone weighing 2 kg with small panels (0.5 m²) could rise into the air for 10–15 minutes every day if it managed to find good weather and a sunny roof. The power required for hovering for such devices is about 150–200 W, and solar panels with 20% efficiency at mid-latitudes can produce up to 350–400 Wh per day. The balance comfortably adds up, especially if not chasing speed and if there’s no rush on the roof.
Such a “solar nomad” could live for weeks and months, flying from roof to roof and charging in anticipation of missions. At first glance, the technology of batteries and panels already allows this to be done. Or am I missing something?
Exploring the Slug: An Unusual Imperial Unit of Mass | July 15 2025, 20:52
Have you ever heard of a unit of mass measurement called a slug? In the US, it does exist, even though it’s less common nowadays. American physics and engineering textbooks for students, especially where they want to clearly differentiate between mass (slug) and weight (lbf), tend to use the imperial system with its feet and the like. It simplifies F = ma in the imperial system without introducing extra coefficients.
1 slug is the mass that accelerates by 1 ft/s² under the force of 1 pound-force (lbf). Thus, a slug accelerating at 32.174 ft/s² “weighs” 32.174 pounds-force (lbf). 32.174 ft/s² is our 9.8 m/s², just in feet.
A “slug” is, on one hand, a slug (a slow-moving mollusk without a shell), and on the other hand, a heavy piece of metal or a bullet (like a shotgun slug – a large-caliber cartridge). In the context of the unit of mass, it’s not about mollusks, but rather about a “heavy lump.” But it’s still funny when they write “mass equals 5 slugs.”
12 slugs equal 1 blob (image of blob attached). Blob is a version of slug, but based on inches instead of feet. It has fun slang names – slinch, slugette, snail.
I also read about the British Thermal Unit — the amount of heat needed to heat 1 pound of water by 1°F. Converting BTUs to calories or joules results in a quite awkward number.
Exploring the Bubble Method of River Level Measurement at the Potomac | July 06 2025, 19:38
How would you measure the water level in a river? A float? A pressure sensor? Something else? Yesterday, I discovered how it’s done here on the Potomac, and it turned out to be not at all what I had imagined. The USGS engineers are great—they educate passersby by posting a diagram of the operation.
A tube is lowered into the river through which air is supplied in bubbles (through a bubble orifice). A special pressure sensor (Pressure Transducer) measures the air pressure in the tube that is necessary to release the bubbles from it. The higher the water level in the river, the more pressure is required to push the air into the water—because the air pressure in the tube is directly related to the depth of the water (according to Pascal’s law). The bubble method works well even if there is floating debris or ice in the river, which may interfere with other sensors (such as ultrasonic ones). Since the sensor does not contact the water, it always remains dry and clean. Additionally, to prevent data distortion, the system includes an air dryer (Air Dryer), which removes moisture from the air and prevents condensation.
The accuracy of such systems is 1-2 cm in water level for rivers with shallow depths.
Interestingly, the readings are transmitted not through the mobile network, but via satellite.
A Costly Trip to the National Cryptologic Museum: Enigmas and Espionage | July 02 2025, 14:56
I went to the National Cryptologic Museum yesterday. Indeed, this trip will cost me $1000 because a rock hit the windshield of the new Tesla on the way. Anyway, let’s talk about the museum.
It’s very small. Located on the premises of the National Security Agency. The museum basically consists of three small rooms. One is dedicated to German Enigmas and there exhibits Alan Turing’s Bombe decryption machine, — a device as big as a kitchen in Lobnya, used for systematic decryption of messages encrypted by the Germans using “Enigma.” After the war, Churchill, for reasons of secrecy, ordered all physical traces of the program, including the Bombe machines, to be destroyed, so it’s quite a rare thing. Moreover, there’s only one working Bombe machine in the entire world, somewhere in England, and even that was barely restored. The Enigmas themselves were produced in large numbers, and the museum has two working ones; you can press the buttons and encrypt something.
In the room with computer equipment stands an old Cray, as well as a decommissioned nuclear deterrence hardware server rack taken out of service 15 years ago. It’s not very clear what’s remarkable about this – well yes, old computers, that’s all. The Cray is actually exhibited many places.
Unfortunately, there are no longer exhibits from the Star Gate project — like the blue box shown in the attached photos. The Star Gate project was used by the US government during the Cold War. Many of the psychic spies were based at Fort Meade, tasked with gathering intelligence, detecting enemy agents, and identifying vulnerabilities in the US using “remote viewing.”
Never heard of “remote viewing”? It’s the mental observation of a distant place where a person has never been, in order to gather information about an individual, an object, or specific data. As absurd as it may sound, it’s claimed that the program was quite successful and used until 1995 🙂
Specifically, this little blue machine, PSIFI, is part of that program. For example, it was used to study the impact of consciousness on random processes — like altering the behavior of random number generators through thought, collecting statistics on attempts at psychokinesis — with “hits”, “trials”, “gated hits”, “gated trials” etc., suggesting successful impacts compared to an expected random distribution, biofeedback — the lower part of the panel contains controls and inputs, apparently for electromyography and other biosignals. Overall, a good addition to the UFO research program.
Understanding Road Grade: The Math Behind the 10% Incline Sign | June 30 2025, 19:48
It turns out that the incline (incline, or grade) – the steepness of a road or slope – has quite an obvious definition, but I never really thought about it. It means the ratio of the projection of a line on the terrain to the vertical plane to the projection of the same line on the horizontal. In other words, the magnitude of the incline equals the tangent of the angle between the rise of the slope and the horizontal (the tangent of the angle of inclination).
Thus, a “steep climb” sign of 10% indicates just about 5.71 degrees of inclination. This is arctan(0.1).
It also turned out that formally among specialists when reading the notation, the “%” sign is pronounced as “hundredths.”
Galactic Etymology: Tracing the Milky Origins in the Night Sky | June 29 2025, 12:57
I am looking at photos and reading material about the Milky Way and noticed that the word galaxy (any) essentially means “milky” from Greek. Κύκλος Γαλαξίας. Essentially, lac from lactose, and gala from galaxy essentially come from the same Proto-Indo-European ģlákts. Unexpected.
Exploring Xplor Park: An Engineer’s Marvel in Riviera Maya | June 29 2025, 05:41
I returned from Mexico — visited Xplor Park by Xcaret in Riviera Maya. The park is already 18 years old, but damn, it’s an engineering feat, not just a park. As an engineer, I was walking around with my mouth open.
The park is the size of Moscow’s “Neskuchny Garden”. A significant part consists of kilometers of natural karst caves, formed millions of years ago at the site of the Chicxulub impact crater (the very one that ended the era of dinosaurs). Above the caves are dense jungles. High above the jungles — kilometers of zip lines. The water in the caves is from a natural underground stream, which is filtered through limestone plus some technical structures. Bats fly around, but obviously, they are not wild and are working for food. No wildlife (other than tourists and bats) is present, so it’s pretty well isolated from the outside world. In these kilometer-long caves, completely covered with stalactites and stalagmites, we swam, rafted, and even drove through in amphibious vehicles with gasoline engines (meaning, the ventilation is well-thought-out).
In front of us, three Mexican women failed to control their vehicle and crashed into a tree. Literally — the front wheels of the buggy were above my head. We picked them up walking along the track, sat them back, and about 5-10 minutes down the road, park workers took them away. The girls have something to remember.
The ticket includes a very, very good buffet restaurant. But pictures are essentially a must-buy — a very thoughtful system designed to extract about 100 dollars from a visiting family. Helmets are embedded with a chip, the system classifies the pics on the fly, and at the exit, you can see all your photos and buy them right there. And on the way back to the hotel, you can post on Facebook or Instagram.
Well, we’re back home now, back to work from Monday.
Hi, I'm Rauf Aliev. 