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April 11

Electrotyping of mid-19th century

Even after I looked up electrotyping I still don't get it. Can someone explain what it is in simple layman's terms. I'm reading a biography from a 1915 book and it says, He invented the art of electrotyping in copper, wood-cuts and type such as are used today. In simple terms what does this mean? The book goes on to say, In 1846 he electrotyped in copper the arm of a child. What exactly did this inventor do here?--Doug Coldwell (talk) 10:50, 11 April 2022 (UTC)

It's the same as electroplating, basically, just using a shaped mold which gets filled in with the material being plated (typed in this case, I guess). The way it works is that you have an electrically conductive mold (the cathode), and some kind of metal ions in solution, along with an anode made of the metal whose ions are in the solution, which you are going to plate. If you drive an electric current through the solution, the metal ions pick up the electrons at the cathode, and become reduced to the native metal; at the same time, electrons are taken from the anode, oxidizing the metal to provide more ions to the solution. So long as an electromotive force (i.e. voltage) is correctly applied, the process will continue until the anode runs out. --Jayron32 11:17, 11 April 2022 (UTC)

To respond to your italicised sentence specifically. First a negative mould is made of the object, whether it be an child's arm or more commonly a wood-cut. The mould can be made of a low-temperature setting substance such as plaster of Paris. The mould is coated with a very thin layer of a conductive material, often graphite. From memory (but unfortunately without citations) the conductive surface can be applied directly to the original and can then be taken up by the mould. Then, as jayron32 explains copper is deposited onto this layer creating a negative of a negative = a positive! Once a sufficient layer has been built up for the particular application, it can be parted from the mould and a backing applied as required. Martin of Sheffield (talk) 11:35, 11 April 2022 (UTC)

There was also a papier mache version of the process. Here's a book about it: Stereotyping and electrotyping. ...In fact there are plenty of other books linked to at the foot of the article.  Card Zero  (talk) 12:08, 11 April 2022 (UTC)

Be careful with that book. The first part contrasts and compares the plaster and papier maché methods, but that is for stereotyping a quite different process. Starting on page 112 it only mentions wax as the mould material for electotyping. Martin of Sheffield (talk) 13:53, 11 April 2022 (UTC)

Oh, dammit. Perhaps I'm being confidently wrong.  Card Zero  (talk) 15:49, 11 April 2022 (UTC)

April 12

Matter and antimatter

Has one already carried out a test of bringing together electron and positron beams in accelerators, rather than collision? I wonder if in this case there would be a pairing rather than an annihilation. It is the beta minus and beta plus decays that make me think that, because then one could imagine the proton composed of pairs of positron electrons, plus a positron to give a positive electric charge equal to the negative charge of the electron, then that the neutron would only be composed of positron electron pairs to remain neutral. In addition, it would give an equivalent number of matter and antimatter in the universe, which would simply have to be renamed as complementary matter. Malypaet (talk) 21:33, 12 April 2022 (UTC)

See positronium for the pair, dipositronium for a pair of pairs. Each of these is much lighter and bigger than a neutron. Graeme Bartlett (talk) 21:36, 12 April 2022 (UTC)

There needs to be enough antimatter mass (there isn't a lot around because it annihilates stuff) which has been created. See antineutrino, antihydrogen and https://en.wikipedia.org/wiki/Antimatter#Antihelium for the antimatter equivalents. Also there is free neutron decay into protons, electrons and antineutrinos, but neutrons are more stable when they are bound within nuclei. Modocc (talk) 03:00, 13 April 2022 (UTC)

I'm pretty sure that allowing particle beams to cross is a bad idea. Iapetus (talk) 10:17, 13 April 2022 (UTC)

I meant to say to cross with an angle close to zero and therefore collision energy close to zero, to see if in this case we still have annihilation or pairing. Malypaet (talk) 22:08, 13 April 2022 (UTC)

Okay. Alright, important safety tip. Thanks, Iapetus. --47.147.118.55 (talk) 06:14, 15 April 2022 (UTC)

Sorry, what are you on about with regard to the composition of the protons and neutrons? Protons are NOT made of "pairs of positron electrons, plus a positron to give a positive electric charge equal to the negative charge of the electron". Likewise your odd explanation of neutrons. Protons and neutrons, as you can clearly read at the relevant Wikipedia articles, are composed of quarks. If you start with incorrect premises, you're going to arrive at nonsense conclusions. --Jayron32 11:46, 13 April 2022 (UTC)

Yes I read wikipedia a lot, but I'm naive. So when I read there that a neutron which emits an electron and various objects transforms into a proton, the same goes for a proton which emits a positron and various to transform into a neutron, I find it easier to imagine these assemblies (lego! ) of electron/positron pairs, rather than quarks which lay the equivalent of an electron positron + various pair to bring a neutron back to its official mass. Besides, has anyone weighed the resulting neutron to verify that it has the official mass?

Who has seen a quark? And the muon which loses its electron (or muon+ its positron), no quark here? Malypaet (talk) 23:19, 13 April 2022 (UTC)

Also the electron proton collision can give a neutron Malypaet (talk) 23:29, 13 April 2022 (UTC)

Who has seen a neutron? All kinds of interaction of subatomic particles are possible, which can go any of several ways (see Feynman diagram), but are constrained by the conservation laws. One of the quantities that is conserved is charge, which works here: −1 + +1 = 0. Another conserved quantity is baryon number. The baryon number of a neutron is +1. The electron and positron both have a baryon number of 0, so they do not combine to form a neutron.  --Lambiam 07:57, 14 April 2022 (UTC)

Per Lambiam, you've never seen a neutron, or an electron, or any of these particles. Saying that you find it easier to imagine things the wrong way doesn't actually make them correct, and per the GIGO principle, if you start with incorrect information, conclusions you draw from such starting places are going to be wrong. --Jayron32 17:08, 14 April 2022 (UTC)

I highly recommend reading Professor Matt Strassler's articles on particle physics. Here is the first of a series on why particles decay to produce other particles. This begins going into the properties of protons and neutrons. See "Articles" in the top of page for a full listing. --47.147.118.55 (talk) 06:14, 15 April 2022 (UTC)

April 14

A plant in Sussex

An unidentified plant in Sussex

Could anyone identify for me this plant which is growing in my Father's garden in Sussex, England? Thank you, DuncanHill (talk) 21:11, 14 April 2022 (UTC)

Some variety of Euphorbia, from the look of it. Mikenorton (talk) 21:18, 14 April 2022 (UTC)

Perhaps Euphorbia amygdaloides var.robbeia, known as Mrs Robb's bonnet apparently. Mikenorton (talk) 21:23, 14 April 2022 (UTC)

@Mikenorton: That looks like it - the article says it thrives in the dry shade of trees, which the ones at Dad's are. DuncanHill (talk) 21:27, 14 April 2022 (UTC)

Probably Euphorbia Amigdaloides.

I advise you to use the free "iNaturalist" application on your Smartphone, so you can identify the plants on the spot. It refers to wikipedia once identified if you wish. Malypaet (talk) 23:13, 14 April 2022 (UTC)

April 15

Cats with the same or similar fur pattern

How probable is it that there are two or more cats (of either sex) anywhere with the identical or very similar fur color pattern (not only twins)? 212.180.235.46 (talk) 18:21, 15 April 2022 (UTC)

Black cats all look pretty similar to me! However, I guess their mothers can tell them apart.... Mike Turnbull (talk) 19:27, 15 April 2022 (UTC)

Seal point Siamese cats, while not monochrome, have very similar coats. The European shorthair has a distinctive stripe pattern, but it is not hard to find a pair that is difficult to tell apart. For calico cats it is hard to find a really similar pair; assigning a probability (which would have to be done experimentally) requires a workable operationalized definition that draws a line between "very similar" and "not very similar". See how many similar-looking couples you can spot here – but be aware that some photos show the same cat in different poses. If n is large enough and you find s very similar pairs, the probability is roughly 2s/n².  --Lambiam 22:31, 15 April 2022 (UTC)

All white Persian breeds have the same (lack of) pattern. Van cats are especially similar down to skull shape and eye color. 97.82.165.112 (talk) 00:29, 16 April 2022 (UTC)

While the validity of Lambiam's caveat (regarding a firmer metric of what constitutes 'similar') cannot be questioned, I can nevertheless tell you with some certainty that the probabilities are actually extremely high, if we are talking about Felis catus. I've done a lot of domestic, feral, and wild cat rescue over the course of my life and have had an opportunity to observe how Mendelian inheritance plays out in coat pattern expression/phenotypes of various breeds, and I can tell you that I have many times seen nearly identical cats be spit out by the same breeding group, sometimes as siblings, and sometimes generations apart. Indeed, in a given breeding pool, even when you do not get near-identical pairs, you will often see numerous cats sharing a large number of idiosyncrasies in the expression of patterns in their fur. On the converse side, however, remember also that expression of the genes controlling appearance can be heavily influenced by epigenetic factors, both in utero and during juvenile development: even genetic twins will sometimes end up looking quite differently after variant environmental factors and diet. I realize this isn't the most empirical or precise of data to answer your inquiry with, but rather an impressionistic answer to your question, but let me put it to you this way: if you were to raise 30-40 cats from one maternal line across 3-4 generations, I would bet you would end up with at least two or three pairs that you would probably be able to tell apart easily enough, but who would confuse the hell out of anyone not super familiar with them. SnowRise ^{let's rap} 15:26, 16 April 2022 (UTC)

The definition of "twin" in a species that produces litters can be problematic. Most cats are fraternal twins inasmuch as they come with other kittens from a single pregnancy, but the kittens may only be half-sibs. A queen on heat will mate with multiple toms, given the opportunity, and so some of the fraternal twins are only half-twins! Martin of Sheffield (talk) 16:46, 16 April 2022 (UTC)

Well, arguably I used nomenclature that was too imprecise, in an effort to keep the info accessible to the OP, but I was specifically talking about monozygotic twins: even these can end up having markedly different coats as they develop, which is a surprise to many people, as it feels unintuitive to their experience/understanding of the largely identical nature of most human monozygotic twins. Of course the truth is is much more complex than that with humans as well, but that's the common perception. SnowRise ^{let's rap} 20:28, 17 April 2022 (UTC)

April 17

Wood in motor cars

Which was the last production motor car that used wood in the main structure or frame of the vehicle, i.e. not just as a decorative interior feature? Thanks. 86.181.187.25 (talk) 19:29, 17 April 2022 (UTC)

The Morgan Motor Company still does this. Bazza (talk) 19:34, 17 April 2022 (UTC)

Surely, it's less safe than metal? 86.181.187.25 (talk) 19:37, 17 April 2022 (UTC)

Morgan claim it's safer. DuncanHill (talk) 19:57, 17 April 2022 (UTC)

I wonder what's worse: To be impaled by a piece of wood or a piece of metal? --←Baseball Bugs ^{What's up, Doc?} carrots→ 06:07, 18 April 2022 (UTC)

Are you a vampire? Then wood is worse unless the metal is silver, particularly when coated in garlic.  --Lambiam 07:06, 18 April 2022 (UTC)

So it's the upper body structure, covered in aluminium sheeting, rather than the chassis. "Morgan’s research shows that the wooden frame makes its cars safer than conventional steel frames on impact tests." Doesn't the UK Government have to do independent tests? Thanks. 86.181.187.25 (talk) 07:40, 18 April 2022 (UTC)

Neither the USA or the UK governments routinely do crash tests. Instead the manufacturer gets their cars tested at a crash test facility. I think in theory you can get a car into production using your own test lab. Greglocock (talk) 09:47, 18 April 2022 (UTC)

The Marcos 1800 GT, 1964, had a wooden chassis, if that helps.  Card Zero  (talk) 09:03, 18 April 2022 (UTC)

You do have to watch where the wood is fiited. Martinevans123 (talk) 09:30, 18 April 2022 (UTC)