Tag: science

Exploring the Engineering Marvel of the Hoover Dam | April 25 2025, 21:56

I watched a cool documentary about the Hoover Dam. We visited it 10 years ago when we were traveling through California, and the impressions are hard to put into words. Just now, I finally got around to finding out how it was built, and four days ago Animagraffs released an hour-long video with “x-ray style” 3D animation that details every aspect of the construction. Friends, it’s like the pyramids of Egypt, only projected onto the early 20th century and tech levels of that time.

First off — the gigantic volume of concrete. The dam contains enough to fill ~5850 average American homes. That’s roughly the amount needed to build a road from San Francisco to New York.

Next, you can’t just pour all the concrete in one go. If the concrete had been poured as a single solid block, the heat generated during curing would have dissipated over about 125 years, which would likely have caused fatal structural cracks. A complex system of pipes with chilled water was embedded in layers of concrete to artificially cool it down. I didn’t even know such a problem existed. Thanks to this design, the dam itself can physically last up to 10,000 years and will become one of the last visible and recognizable monuments of humanity on the planet. (Incidentally, the largest dam built by beavers is in Alberta, Canada — twice as wide as the Hoover Dam — and it’s visible from space. Just something that came to mind).

Extensive “grouting” was conducted — injecting cement slurry under pressure deep into the rocky foundation (up to 150 feet for the main “grout curtain”) to fill cracks and, essentially, “weld” the dam to the canyon, preventing leaks and uplifting pressure from water.

The dam was not poured monolithically. It was constructed from interlinked vertical columns built in 5-foot “lifts” (layers) to manage the heat release, control cracking due to expansion/compression, and ensure structural integrity. The video beautifully demonstrates this.

Four massive tunnels (17m/56feet in diameter, about 3/4 mile long each) were bored just to divert the Colorado River. Instead of abandoning them, they were later plugged and incorporated into the permanent structure as part of the intakes (penstocks) and emergency spillways.

“High Scalers”: Workers known as “high scalers” were lowered hundreds of feet down the sheer canyon walls in simple bosun’s chairs, using jackhammers and dynamite to remove loose rock.

Giant aerial trams: An extensive network of cableways crossed the canyon, including one with a capacity of 150 tons, which was used to move massive equipment (even trucks) and concrete buckets.

Special heavy-duty equipment: For the project, special trucks were developed with doubled load capacity, greater power, and frames made of lightweight aluminum alloys.

The emergency spillways have a total capacity of 400,000 cubic feet per second – about four times greater than the average flow of Niagara Falls during peak season.

In the spillways, massive, 100-foot tall hollow drum gates are used, which float at the water level in their chambers, automatically rising or falling to manage floodwaters. Quite an interesting engineering structure — no motors and designed to handle severe loads.

Despite its scale, the dam was officially opened in 1936, significantly ahead of schedule (construction began in 1931). Revenue from power generation had fully paid for the construction cost by 1987.

Link at the bottom, or Google Animagraffs Hoover

Recent Russian Popular Science Book Recommendations | April 25 2025, 02:49

Recommend something worthwhile from popular science in Russian — probably something that has been released in the last year and a half.

I’m organizing additions to my bookshelf – this time from publishers in the Russian language.

Dumplings and Density: A Culinary Physics Exploration | April 18 2025, 18:08

Suddenly, it hit me – why not have some dumplings? So now, for the second day in a row, I’m devouring dumplings, with three different kinds in the fridge already. Plus, I bought some herring, and Nadya, without coordinating, also brought some. The fridge is surprised; it hasn’t seen either in a long time.

So, while I eat another serving, I’m googling why dumplings float. It’s not trivial, by the way.

Overall, the physics of this floating process is complex. They don’t float just because. Let’s start with the dough. It contains starch which absorbs water and swells (gelatinization), increasing the volume. Inside, the proteins in the dough denature, creating a more rigid structure. Some water evaporates/boils, forming bubbles. Result: the density of the dough decreases, aiding the floating. Meanwhile, the proteins in the meat also denature, become denser, and release moisture, decreasing the meat’s volume. The fat melts. Thus, for the meat itself: density increases, which counters the floating. Moreover, water penetrates inside the dumpling where it wasn’t before, also acting against the floating, as it simply becomes heavier. But the moisture released from the meat (juice) and water in the meat itself can boil, forming steam bubbles inside the filling. These bubbles offset the densification of the meat, and overall density of the filling also decreases (or remains the same).

In the end, the reduction in density of both the dough and the filling (due to the bubbles) leads to a decrease in the overall density of the dumpling, making it float.

Salt barely affects the cooking speed. Although salt raises the boiling point of water (Raoult’s law), to significantly speed up cooking, you’d need to add so much (10g per 2L) that the dumplings would become unbearably salty. In normal amounts, salt is just for taste.

Also, there is such a phenomenon as osmosis which is the reason for the tasty broth. Water penetrates inside the dumpling through the porous dough (osmosis), making the filling juicier. Substances from the filling leach into the water, making the broth tastier and fattier.

Curating a Diverse Bookshelf: Art, Science, and Beyond | April 18 2025, 17:28

The books requested a new home. Brought the home, settled the home, group photos from the housewarming.

Fed the pics to ChatGPT, got a booklist. Edited a bit, it makes mistakes.

Top shelf – art. I only keep the best in the list:

1. Alla Prima II by Richard Schmid

2. Virgil Elliott – Traditional Oil Painting

3. Anatomy for Sculptors – Uldis Zarins

4. Anatomy of Facial Expression – Uldis Zarins

5. Form of the Head and Neck – Uldis Zarins

6. Impressionism by Bomford, Kirby

7. Lessons in Classical Painting by Juliette Aristides

8. The Practice of Oil Painting & Drawing by Solomon J. Solomon

Second shelf – science and other science pop

Sergey Yastrebov “From Atoms to the Tree” (biology, chemistry)

Kukushkin – Clapping with One Hand (biology)

Burlak — The Origin of Language (linguistics)

Eric Kandel – In Search of Memory (biology)

Andrew Solomon- Far from the Tree (biology)

Richard Dawkins – The Selfish Gene (biology)

Yuval Noah Harari – Sapiens (history)

Yuval Noah Harari – Nexus (history)

The Elegant Universe, Brian Greene (physics)

Carl Zimmer – Life’s Edge (biology)

Carl Zimmer – She has a mother’s laugh (biology)

Semikhatov — Everything That Moves (physics)

Poluektov – Mysteries of Sleep (psychology)

Noga Gál – The Living and the Dead Word (linguistics)

Kitaigorodsky – Entertaining Theory of Probability (mathematics)

Steven Pinker- How the Mind Works (biology, psychology)

Robert Sapolsky – Determined (biology, psychology)

Neil deGrasse Tyson – Accessory to War (astrophysics)

Flavor by Bob Holmes (biology)

Jared Diamond – Guns, Germs, and Steel (biology)

Marilyn Sheldrake – Entangled Life (biology)

Wolfram – A New Kind of Science (mathematics)

Frans de Waal – Are We Smart Enough to Know How Smart Animals Are? (psychology)

Eidelman – How Propaganda Works (psychology)

Peter Godfrey – Metazoa (biology)

Asya Kazantseva – Who Would Have Thought! (hard to say)

Asya Kazantseva – Someone Is Wrong on the Internet (–“–)

Asya Kazantseva – The Brain is Material (–“–)

Gordon – Structures, why things don’t fall down (architecture)

Thomas Heatherwick – Humanize (? design, architecture?)

Ed Yong – I Contain Multitudes (biology)

Po Bronson, Arvind Gupta – Decoding the World (biology)

Jonathan Haidt – The Anxious Generation (psychology)

Plus, some books there are biographies and fiction. Unfortunately, many good books I’ve read and would like to put on the shelf are not in paper but in digital or left behind in a past life.

Recommend what else I might like.

Exploring the Intriguing History and Ecology of Kangaroos and Camels | April 17 2025, 22:47

Interesting. It turns out that before Russia imposed a temporary ban on kangaroo meat imports, it consumed 70% of all kangaroo meat produced in Australia.

It turns out that not only do camels roam in Australia, but there are more of them than in Central Asia and the Middle East, and Australia actively sells them to Saudi Arabia, for instance. Moreover, camels were introduced to Australia from the Middle East by Afghans, who left quite a significant (and positive) mark on the history of Australia.

For example, here’s a photo of the Ghan train — it features a camel on its logo. This is no coincidence; it is actually named after those Afghans who brought the camels.

Also interesting is that camels are originally from our regions. Yes, the USA is, in fact, the homeland of camels. According to some estimates, camels first appeared in North America between 40 and 50 million years ago, and 3 million years ago, they crossed into Asia via a land bridge in the Bering Strait area, and then made their way to Africa. In recent years, convincing evidence has been found that these animals inhabited almost all of North America. And of course, the climate was different back then.

Moreover, I read that there is such a thing as “kangatarianism” — a practice of following a diet that excludes the meat of all animals except kangaroo, for environmental and ethical reasons.

Also, it turns out that there are tree kangaroos (Tree-kangaroo). Also, in English, a group of kangaroos is called “a mob” – a gang 🙂 However, in Australian English, mob is not used in the same connotation as “mafia” or “gang”. Indeed, a group of crows with their “murder of crows” isn’t too far off either.

Oh, how could I not mention etymology! There is a legend that the word “kangaroo” means “I don’t understand”. I thought so too until I looked into it.

Actually, “kangaroo” originates from the Guugu Yimithirr language, an Indigenous language of northern Australia, where gangurru specifically refers to a type of kangaroo. But it’s not that simple 🙂

It all starts when James Cook asked the Guugu Yimithirr what the animal was called — they answered gangurru, which did indeed denote it. The English borrowed this word as kangaroo.

Latter, half a century later, the etymology starts to get tangled. In 1820, a certain Philip King sailed along a river near Cook’s landing place and recorded a list of words from the local Guugu Yimithirr dialect. Everything matched Cook’s records — except for one word. When asked “what is that animal called?”, they didn’t answer gangurru, but minha. It means that Cook clearly made a mistake. If minha is “kangaroo”, then what is gangurru?

This is where the myth begins. Some begin to think: maybe Cook misunderstood? Maybe he asked about the animal, and they didn’t understand him — and gangurru meant “I don’t know”? This version is a fabrication, and it didn’t go further than speculation, but it’s a funny story, historically plausible, and it began to be repeated. Thus, it turned into a persistent legend.

Then the confusion reversed. “Kangaroo” — then and now — became the stereotypical word from the “aboriginal language”. Every European settler coming to Australia knew exactly one word from Guugu Yimithirr — and only that one. The problem is that there were hundreds of languages in Australia, many of which were weakly or not at all related to Guugu Yimithirr. They simply did not have the word gangurru or its equivalent.

That’s where the problems arose. For example, settlers arrived in the area of modern Sydney and tried to “communicate” with the local people, i.e., they just yelled “kangaroo” at them. This would hardly have helped, but it is important to remember the geography: the Guugu Yimithirr lived on the Cape York Peninsula, in the far north of Australia, and the Sydney aborigines — the Iora people, speaking Dharuk language — lived almost at the other end of the continent. They didn’t know what the word “kangaroo” meant, so they assumed the Europeans were particularly interested in their domestic livestock. When cows began to be unloaded from the ship, the locals asked: “Is this your ‘kangaroo’?”

Such is the story.

Also, it turns out, kangaroos are good swimmers. In the second photo, a kangaroo tail sold in our town. For the dogs to gnaw on.

Unraveling Danish Numerical Peculiarities | April 17 2025, 16:58

Today I learned something interesting about numbers. Turns out, the French are not the most convoluted when it comes to naming the tens up to a hundred. It seems the Danes hold that title.

In Danish, 92 is “tooghalvfems. It breaks down like this: “to” is two (2), “og” means and, and “halvfems” is 90. But why halvfems? halv means “half,” that much is clear. However, in this context, it’s not literally 0.5. When used with numbers ending in “-fems,” it signifies “minus half of the next multiple of twenty. Then comes fems: This is a shortened form of fem gange tyve, which means “five times twenty, thus, halvfems translates to “halfway into the fifth twenty”. The fifth twenty ranges from 80 to 100. Halfway equals 90 🙂

50 is “halvtreds” in Danish. Here “halv implies “halfway to the next multiple of twenty”. treds is the condensed form of tredje sinde tyve, which translates as “three times twenty, or 3 × 20 = 60. Thus, halvtreds can be understood as “halfway to sixty, that is: 60 – (0.5 × 20) = 60 – 10 = 50.

It’s clear that this is because of the vigesimal (base-20) numbering system.

I recalled the French because they too have 80 = quatre-vingts (four twenties), 90 = quatre-vingt-dix (four twenties and ten), 75 = soixante-quinze (sixty and fifteen).

P.S. Thanks to Timofey for the tip

Exploring Surprising Etymological Connections | April 10 2025, 20:20

The sixth day of etymological curiosities, #RaufLikesEtymology. My script is still running, which parses dictionaries and finds unexpected pairs and groups of words with a common origin but different destinies. Today features an entire series of such etymological doublets and even triplets.

Canvas (canvas), cannabis (cannabis), and hemp (industrial cannabis) are relatives. All three stem from the ancient word κάνναβις (kánnabis) — “cannabis,” possibly of Scythian or Thracian origin. Cannabis came directly from Latin, denoting the plant. Canvas came through French canevas — it’s a fabric, initially made from hemp fibers. Hemp came through Germanic languages (Old English henep), all with the same root (henep<-hanapiz<-cannabis).

Cannibal, Caribbean, and Carib — another intriguing triplet.

The word cannibal is a corrupted form of Cariba, as Columbus and his crew called the local tribes. They were thought to be cannibals. Caribbean — a geographical name of the same root. Carib — an ethnonym, the self-name of the people. Thus, “cannibal, “Caribbean, and “Caribs are words from one etymological family, just with different reputations.

Deutsch and Dutch (as the Japanese call Germany) are etymological twins, all stemming from one Proto-Germanic root þeudō — “people.” Deutsch is “German” in German, literally “people’s language.” Dutch formerly referred to any Germanic people, now strictly the Dutch.

Doitsu — a Japanese loanword from German, introduced through exchange in the 19th century. But in general, each neighboring country calls Germany differently in their languages because Germany as a single state appeared relatively recently (in 1871), and before that, it was a mosaic of separate principalities, duchies, free cities, and other political entities. Hence, different names have become entrenched in various languages — most often not for all of Germany, but for a particular tribe, region, or ethnic group. The French call it Allemagne — from Alemanni, Italians — Germania, but in casual conversation might also say tedesco (German), from the same root as Deutsch, Latvians — Vācija, from an ancient Baltic word meaning “foreign or “foreigner, Finns and Estonians — Saksa and Saksamaa, from the Saxons — one of the Germanic tribes, Poles — Niemcy, from the Slavic němьcь, meaning “mute — those who don’t speak “our way,” are unintelligible. The same root is also in Old Slavic.

However, the Japanese say Doitsu — an adaptation of German Deutsch through Dutch intermediation, as the first Europeans to actively trade with Japan were indeed the Dutch.

Species and spice — both from the Latin speciēs, meaning “appearance, form. Species retained its scientific meaning — “species. Spice came through Old French espice, initially meaning “rare goods, and then narrowed down to “spices.” So spices are also “forms, just aromatic ones.

Corpus, corpse, corps — all from the Latin corpus (“body). But “Corpse” — a dead body, came through Old French cors, and “Corps” — an army corps, pronounced as “core, stuck with the French pronunciation, and “Corpus” — a legal or scientific “assembly of bodies, used in the academy.

Map and mop — etymological twins. Both originate from Latin mappa — “cloth, napkin. Simply, one through Old French became “map (because maps were drawn on fabric), and the other — “mop (by the direct use of the fabric).

Read more such goodness by clicking here —> #RaufLikesEtymology

Exploring the Roots: A Daily Dive into Etymology | April 09 2025, 19:25

Day four of fascinating etymology! Here I am, scripting away at processing an etymological dictionary, discovering all sorts of curiosities, and sharing them daily.

The surname Biden likely originates from the verb bide, meaning “to endure, to wait. From the Old English bīdan and Germanic root. However, etymological dictionaries also mention Biden as a phonetic doublet of the root bouter (through the variant beat, “to hit”). Choose whichever you like more.

Interestingly, the word кретин (cretin) in Russian comes from the German word “Kretin” (simpleton). In turn, this word entered the German language from the French “crétin.” The French borrowed it from Latin, where it designated a Christian (Christiānus). By the way, Christ (Χριστός) literally means “the anointed one.”

The words sovereign (ruler, monarch) and soprano (soprano) originate from the same Latin root super — “above, beyond,” but entered the English language through different languages and cultural contexts, acquiring different meanings.

Everyone knows that the word “шедевр” (masterpiece) is French, from chef-d’œuvre — literally “chief work.” Chef comes from the Latin caput — head; hence la capitale (capital), captain, and capitol, which I wrote about a few days ago. And immediately it’s clear why in French chapitre is a chapter in a book, and capiteux means intoxicating, heady. Thus, Œuvre is work, labor. Interestingly, this word traces back to the Latin opera (in nominative case opus). Modus operandi — method of operation. Our operation is of the same lineage. From the same root also come the words ouvrier (worker) and les jours ouvrables (working days). Thus, opera is labor, as is opus. Right now, I’m listening to “Samson and Delilah,” quite fitting.

And this morning, I went to return some Amazon purchases to the Kohl store. They accept them there. So, not sure what else they accept, but Kohl is the same as alcohol. Both words derive from the Arabic root — الكحل (al-kuḥl). Initially, it meant “stibnite — a powdery mineral (usually antimony), used as a cosmetic for the eyes. Later, the meaning expanded in alchemy. First, it referred to any fine powder, then to a concentrated substance obtained by distillation, and finally to alcohol, as a product of distilling wine. In English, Kohl remained associated with cosmetics. But the Kohl’s store, of course, comes from the surname Kohl, German, Maxwell Kohl, and his surname in German means “cabbage.”

The word bedlam (meaning “chaos,” “mayhem”) originates from the name of the London hospital “St. Mary of Bethlehem,” which, since the 1400s, was designated for treating the mentally ill. Over time, the pronunciation of “Bethlehem” shifted to bedlam, and this term came to denote any situation where chaos and confusion reign.

Also, flask (“flask”) and fiasco (“fiasco”) share a common origin — the Proto-Germanic *flaskǭ — “bottle, container, encased container.” In Italian, a fiasco is a bottle. The expression fare fiasco — “to make a bottle” → “to mess up on stage” (in theatrical slang). Metaphorically: failure = “like a broken bottle” or “the loser pays for the bottle.” It entered English with this meaning through French.

It turns out Alice and Adelaide originate from the same Old High German name Adalheidis (adal — “noble,” heid / heit — “nature, essence, condition”).

Array and ready are etymological relatives, originating from the same Proto-Germanic root *raidaz, meaning “ready, organized, prepared.”

Going back to our cretins. I didn’t mention details earlier because it would have disrupted the “flow.” The word “cretin” appeared in Switzerland. More precisely, among the French-speaking people living in the Alps (this area is called Romandy). It’s particularly in mountainous areas where they often encounter endemic cretinism. The disease develops due to insufficient iodine in the mother’s diet during pregnancy.

In the 18th century, in Romandy, patients with cretinism were called “poor Christians” (pauvre chrétien). But they didn’t say chrétien, but crétin due to regional language characteristics. Other regions picked up this distorted word and started using it to describe people suffering from this disease. Hence the medical term “cretinism (when the thyroid gland releases insufficient hormones due to iodine deficiency, leading to serious mental and physical development disorders).

Originally, “cretin” meant “unfortunate Christian” (foolish, blessed). At the end of the 18th century, the term “cretinism” spread through European languages. But it entered the Russian language in the early 19th century via German!

Read more great stuff by clicking here –> #RaufLikesEtymology

Exploring the Intriguing Origins of Words | April 09 2025, 03:51

Well, shall we continue with the fascinating etymology? I’ve been writing scripts for processing an etymological dictionary, and I’m finding all sorts of interesting stuff.

It turns out that the word “ciao” comes from the word “slave”. It derives from the Venetian expression s-ciào vostro or s-ciào su, which literally means “(I am) your slave”. The Venetian word for “slave” — s-ciào [ˈstʃao] or s-ciàvo — comes from the medieval Latin sclavus, which, in turn, was borrowed from medieval Greek Σκλάβος (“sklavos”), itself related to the ethnonym “Slavs”, as most of the slaves during that time came from the Balkans.

Also, it was a revelation to me that the words Kubernetes, governor, and cybernetics are etymologically related. They all derive from κυβερνήτης (kubernḗtēs) — “helmsman, one who steers a ship”. Consequently, governor came through Latin and Romance languages, cybernetics as a scientific loan through French, and Kubernetes as a direct calque from Ancient Greek, via Latin transliteration.

The words fuel and focus originate from the same Latin word focus (“hearth”). Focus was actually coined by Johannes Kepler, who used it as a geometric term for ellipses: “the point where rays converge”.

The words Madeira, mata, mater, matrix, matter, and mother are related and all trace back to the same Proto-Indo-European root *méh₂tēr — “mother”.

The words madam and madonna come from the Latin mea domina — “my lady”.

It’s hard to imagine, but the words merry (cheerful) and brief (short) originate from the same Proto-Indo-European root *mréǵʰus, which means “short”.

The words lobby and leaf also have a common origin — both stem from the ancient Germanic *laubą or its derivatives, related to foliage, leafy shelters, and coverings. In old buildings, laubia/lobby was a covered gallery or arbor, literally a shelter made of leaves. Thus, “lobby originally meant “leafy shelter” or “leafy arbor”.

Common origins or roots also link names like Yuri and George, Étienne and Stephen/Steven, William and Guillermo, Zeus and Jupiter, Zhenya and Yana, Joel and Elijah, Hansel and John, as well as Agnes, Nancy, and Inez, Diego and Jacob, Dorothy and Theodore, and Isabel, Elizabeth, and Lisa, Iskander and Alexander, Patroclus and Cleopatra. Many of these essentially denote the same thing, just modified differently across cultures.

Read more of such good stuff by clicking here –> #RaufLikesEtymology

Exploring Linguistic Connections with #RaufLikesEtymology | April 08 2025, 16:22

I continue with etymological curiosities. This is my third consecutive post, #RaufLikesEtymology. It all started when I stumbled upon an etymological dictionary and began processing it programmatically, extracting all sorts of things.

It turns out that the words “жёлтый” (“yellow”), “зелёный” (“green”), and “золото” (“gold”) share a common Indo-European root related to brightness and luster — *gьltъ, which in English, for instance, became the basis for both gold and yellow. In German, “gelb” (yellow) comes from there too. In Russia, “желтый” has been known since the 13th century as a nickname, and as an adjective in written sources only since the 14th century.

It turned out that “известь” (“lime”) and “асбест” (“asbestos”) come from the same word, the Greek ἄσβεστος.

It turns out that the words шифр (“cipher”), цифра (“digit”), and zero all come from the same word — the Arabic صِفْر (ṣifr, “nothing, zero”), which itself is a calque from Sanskrit शून्य (śūnya, “emptiness, nothing”).

Pushkin wrote in “Poltava”: “In the night’s darkness they, like thieves… // Craft the ciphers of universals…” “Universals” in the Ukrainian language of those days were called Hetman’s edicts, and “цифр” back then meant what we now call a cipher — “secret writing”.

Interestingly, the word “кантон” (Switzerland consists of 26 cantons) – originates from Chinese, from Guangdong.

It turned out that grotto and crypt — come from the same word, Latin grupta/crypta. Well, about Saturday and sabbath everyone knows (that they are one word by origin).

The Russian word “колесо (wheel) and the Indian “чакра (chakra) are linked by origin — both come from the same ancient root in Proto-Indo-European — *kʷékʷlos — “circle”, “wheel”, “rotating”. “Колесо came through the Slavic branch, while “чакра — through the Indian (Vedic-Sanskrit) branch.

The words cloak (“cloak”) and clock (“clock”) derive from medieval Latin clocca — “bell”, but entered English differently. Cloak arrived in the 13th century through French cloque, which meant both “cloak” and “bell” — due to the shape of the garment. Clock appeared later through Dutch clocke, denoting a church bell that marks the time; subsequently, it came to mean “clock”. The word bell (“bell”) already existed in English as a designation for a metallic ringing object, so there was no need to introduce another word for this.

The apricot has had a very interesting journey. Here, look at the attached picture. Borrowed in the early 18th century from Dutch, which itself had borrowed from Romance languages (for example, French abricot). It’s interesting to trace this word further: it turns out that in French, it came from Arabic, and in Arabic from Latin. Latin praecox meant “early-ripening”. Thus, praecox became abricot.

My little script churned out about 2 thousand examples from wiktionary. I pick the most interesting ones, but I think there’s enough material for about five more posts like this 🙂 Plus, I have more ideas on how to process to uncover even more interesting things.

Read more good stuff by clicking here –> #RaufLikesEtymology