Wikipedia:Reference desk/Archives/Science/2021 November 6

= November 6 =

Chemistry reactivity questions.
Suppose A is more reactive than B, as in, A reacts with a bunch of other substances faster than B does. Then can there be cases where B reacts with something better than A does? Note that, I imagine to make this question useful, we must make A and B in the same category of something. Like, A and B should both be metals. So if A reacts with 10 different acids better than B does, can B react with an acid that A doesn't? Or B reacts with a base that A doesn't? Can it be such that B reacts with gases better than A does?

Since this is such a specific question, I'll throw in another 1. Our article on chemiluminescence says the 1st accidental discovery was in 1877. But the source is in German. Just wondering if anyone compiles a list of discoveries of chemiluminescence in order, I'm curious to know what the 1st discovery is by theory and not by accident. I'm also wondering if anyone discoveries chemiluminescence in say, the past 20 years, by accident, or and by theory still. 67.165.185.178 (talk) 14:51, 6 November 2021 (UTC).
 * for your first question the answer is yes. Consider aluminium and copper. When exposed to water and air copper reacts much faster to make a green covering. But aluminium dissolves much better in acid than copper. This is because aluminium forms a protective film. Sometimes the compound produced can be unstable, so for example, lithium reacts with nitrogen, but potassium does not. Or sometimes a stable complex can be formed. For gold, it is pretty tough to react or dissolve, but with air and cyanide it can dissolve. Graeme Bartlett (talk) 21:29, 6 November 2021 (UTC)

Ducks and geese don't have crops?
See the recent edit to crop (anatomy) here. The anon rightly points out in his/her edit summary that the article states that ducks and geese don't have crops, but the article is illustrated with an image and a video showing a duck and a goose, apparently with a bulging crop. I have found some websites (e.g. this) that say that ducks and geese don't have crops too. So I have no idea. Anyone able to help? I only really know about parrots to any great extent. --Iloveparrots (talk) 20:26, 6 November 2021 (UTC)

I found lots of links saying they do, including dissected ducks. Greglocock (talk) 22:49, 6 November 2021 (UTC)


 * @Greglocock - I just saw you'd edited the article. I added something else myself. But... the source you added for ducks - is that not a photo of a dissected chicken? Look at the head... --Iloveparrots (talk) 22:54, 6 November 2021 (UTC)


 * Farm Animal Behaviour: Characteristics for Assessment of Health and Welfare (p. 234) by Ingvar Ekesbo and Stefan Gunnarsson says:
 * Unlike many birds, geese and ducks lack a crop.
 * The authors are both professors at the Swedish University of Agricultural Sciences (SLU), so probably know their onions.
 * Alansplodge (talk) 13:22, 7 November 2021 (UTC)


 * See also:-
 * Domestic ducks, like their wild forebear, the Mallard, do not have a crop...
 * Ducks do not have a crop to store food...
 * Unlike most birds, ducks and geese do not have a crop. This outpouching of the oesophagus allows some storage of food before digestion proper begins. In ducks and geese, the whole oesophagus is stretchy and expandable, ..
 * Ducks do not have a crop to store food, unlike the chicken. Food is stored in the gullet and proventriculus in a similar way to the crop,
 * The last quote is from Anaesthesia for Veterinary Nurses Alansplodge (talk) 13:41, 7 November 2021 (UTC)


 * Here are the FAO saying that geese do have crops. Its oesophagus is relatively long, with mucous glands to lubricate the passage of food and extends into the spindle shaped crop that serves as a reservoir for food storage. DuncanHill (talk) 13:53, 7 November 2021 (UTC)


 * The problem is that anatomy and biology are largely 'stamp collecting' to quote Rutherford, possibly. If a crop is defined as a thing that ducks and geese don't have, then they don't have one. If a crop is defined as part of the gullet where food is stored before hitting the stomach, then they do have one. I'm not interested in arguing about stamp collecting. Greglocock (talk) 21:51, 7 November 2021 (UTC)
 * Naming body parts by the function they serve indeed has its value for some analyses. But for other analyses in biology it makes sense to name homologous structures consistently, so that we can recognise how they have evolved, how they develop in the embryo, and, for instance, how the nerves innervating them are wired up. Thus there is value in referring to the wing of a bird, the front leg of an elephant, and the arm of a human as the forelimb even though their functions are very different. Recognising homology is not to be dismissed as stamp collecting. Jmchutchinson (talk) 17:00, 8 November 2021 (UTC)


 * Perhaps the Wikipedia-like way of solving this is to record in the article that there are differing opinions? Alansplodge (talk) 00:15, 8 November 2021 (UTC)
 * Or differing definitions.--Shantavira|feed me 09:45, 8 November 2021 (UTC)