December 17, 2024
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January 2025: History of science 50, 100, and 150 years ago
J particle. nitroglycerin engine
1925, Exercises in motion: “Years before the invention of cinema, Eadweard Muybridge at the University of Pennsylvania used electrically timed cameras to study the precise movements of human muscles during exercise. Background The crosshairs were used to accurately measure each movement. This image is from an edition copyrighted by Eadweard Muybridge in 1887.
scientific americanVol. 132, No.1. January 1925
1975
Thunder Crack or Thunder Rumble
“Lightning flashes last only a few tenths of a second. Why do the resulting sounds last 30 minutes or more? A typical lightning discharge travels through a waterway about 10 kilometers long. 3 The light from all parts of the channel reaches the observer almost instantly, but the sound from different parts usually reaches the observer at different times. , perpendicular to the line of sight , the sound reaches the observer almost simultaneously. If the channel is approximately parallel to the line of sight, the sound from the farthest part will be observed many seconds later than the sound from the nearest part. It’s a long rumbling sound.
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J particles may be attracted to quarks
“The most puzzling aspect of the new types of subnuclear particles recently discovered by two high-energy physics laboratories is their unusually long lifetimes of 10 years.”–20 Number 2. This unexpectedly “slow” decay distinguishes this relatively huge new particle from the hundreds of other unstable subnuclides produced in particle accelerators. Most of the latter particles have a lifetime of around 10.-twenty three Number 2. This new particle is called the J particle by one group of experimenters and the psi particle by the other group. Another possibility being discussed is that this particle represents a “bound state” consisting of a “charmed” quark and its corresponding antiquark. ”
1925
Does lactic acid cause muscle fatigue?
“What happens when you’re out of breath or exhausted?” Dr. AV Hill, Professor of Physiology at University College London, recently researched the effects of exercise fatigue and the use of a certain chemical called lactic acid in the muscles. Dr. Hill found that while fatigue is accompanied by an increase in the amount of lactic acid in the muscles, recovery from fatigue always involves a decrease in lactic acid. I discovered that.”
Scientists discredited the lactic acid idea more than 20 years ago, and it remains strong today. They suspect that inorganic phosphates may contribute to skeletal muscle fatigue.
1875
chromosphere covering the sun
“The edge of the Sun’s visible disk, between 8,000 and 10,000 miles altitude, is covered by a rose-colored envelope of gas, Lockyer named it the chromosphere, a scarlet flame that covers the entire surface of the sun and rises in cloud-like shapes in places, rising to great heights. showed that they are just clouds of heated gas, mainly hydrogen. The spectrum clearly shows the element’s bright line, as well as another very prominent line. The name helium was given to this hypothetical element by Lockyer and Edward Frankland. However, its validity is highly questionable.
Wanted: Nitroglycerin engine
“M. Champion, a French chemist, said that the heat produced by a given quantity of nitroglycerine during an explosion, when converted into motion, produces five times the maximum energy produced by the explosion of the same quantity of gunpowder, and 3,000 times as much. It says it can deliver twice as much energy as burning the same amount of coal. It is claimed that one quart of nitroglycerin has a potential energy of 5,500 horsepower that will operate for 10 hours. It remains to invent a machine that can harness and control enormous forces.”
Monorail with leather brakes
“The Turkish government recently began construction of a railway called the Steam Caravan, a distance of 154.2 miles between Alexandretta and Aleppo, Syria.1 with walls 28 inches high and 17.5 inches wide. A book rail is installed. The car straddles both the rail and the wall. The locomotive has horizontal leather-covered wheels that rest against the sides of the masonry to act as brakes. The last car of each train has a similar arrangement, with two people on each side, giving the train a total capacity of 96 people.
