Wikipedia:Reference desk/Archives/Science/2022 November 17

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November 17

Greatest science achievements from Australia?

Textbooks in the U.S. on science all list historical achievements from the U.S. and Europe. Probably none from Australia? Wikipedia's article even on TV remote control and garage remote control all says invited in U.S. I would like to see a textbook used in Australian colleges on biology, chemistry, and physics - even horticulture, to see if they actually list inventions/discoveries from Australia? I already had an earlier discussion on this page that the 1st genetically-modified blue rose was done in Australia, with the help of a Japanese company. Wonder what are some other famous 1sts in Australia. I would imagine a horticulture/botany textbook from Australia will be vastly different than in the U.S. or U.K. Anyone have who were the 1st from Australia to win the Nobel prize in sciences? 67.165.185.178 (talk) 02:34, 17 November 2022 (UTC).

Start with Timeline of Australian inventions. List of Australian Nobel laureates may also be of interest. For a deeper dive, try Category:Australian science and technology awards-gadfium 03:40, 17 November 2022 (UTC)

One invention highly relevant to most communication here is WiFi HiLo48 (talk) 06:17, 17 November 2022 (UTC)

• Adding bubbles to beer. --Jayron32 12:33, 17 November 2022 (UTC)

What is the basis for which metal detectors detect liquids?

Which would mean, metals and liquids, have some common-ality. Does that mean metal detectors can detect water, but not ice? 67.165.185.178 (talk) 04:33, 17 November 2022 (UTC).

Detection by metal detectors is based on electrical conductivity, which is about seven orders of magnitude higher for metals than for water, fluid or frozen. In other words, metal detectors are just as useless for detecting liquids (other than mercury) as dowsing rods.  --Lambiam 08:52, 17 November 2022 (UTC)

Yea, metal detectors in airports and court buildings do a good job detecting liquids, so. 67.165.185.178 (talk) 04:04, 20 November 2022 (UTC).

And dowsing can work. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:34, 20 November 2022 (UTC)

The liquid detectors used at airport security checkpoints are based on Raman spectroscopy or Computed Tomography (or a combination of both), typically using high-energy X-rays. These methods are completely different from the technology used in metal detectors.  --Lambiam 19:39, 20 November 2022 (UTC)

Raman spectroscopy that will be the least bit useful at airport security checkpoints won't be using x-rays as their excitation. Typically, they will use something in the UV-Vis-NIR range. While X-ray Raman scattering is a thing, it's generally providing atomic level details on the core electrons, which isn't terribly useful from a security perspective. On the other hand, more traditional Raman spectroscopy in the UV-Vis-NIR range provide molecular information, and are particularly adept at detecting things like explosives (especially peroxide based explosives, which are otherwise difficult to detect as they lack nitrogen). You are correct that CT mainly uses x-rays. --OuroborosCobra (talk) 20:55, 20 November 2022 (UTC)

Oh wait, the metal detectors are for where the human walks underneath a metal detector (like for courts). The thing that detects liquids is the topography where the bag goes through in a tunnel? But the tunnel detects metals too, so the tunnel is running 2 things at the same time? But those wands that the security guards wave around you also detect liquids. 67.165.185.178 (talk) 01:06, 21 November 2022 (UTC).

What makes you think the wands the security guards have detect liquids? --OuroborosCobra (talk) 18:48, 22 November 2022 (UTC)

Experience. But this was from security from working at UPS / FedEx rather than going to court. In fact, the courts for state court are weaker than federal court it seems, for the walk-through, in which federal court metal detectors can detect a watch, the state courts do not. 67.165.185.178 (talk) 22:28, 22 November 2022 (UTC).

As far as I can find, your experience is incorrect. Wands are metal detectors. You would need something like backscatter X-rays or millimeter wave scanners for something like detecting liquids. Both of these are done with full body scanners, and not "wands". --OuroborosCobra (talk) 23:27, 22 November 2022 (UTC)

My mom's menstrual cycles

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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My mom has painful menstrual cycles every other one (her average menstrual cycles are about 30.5 days long. One menstrual cycle, she could barely feel it, but the other one seems to be the "hurtful" one. She takes a Midol whenever those cycles come. Why is that, I wonder? 67.215.28.226 (talk) 04:52, 17 November 2022 (UTC)

Questions asking for medical advice, which this is, are not allowed here. Sorry. --174.89.144.126 (talk) 05:33, 17 November 2022 (UTC)

Oh, okay. 67.215.28.226 (talk) 05:45, 17 November 2022 (UTC)

Without being diagnostic: consider the fact that women usually have two ovaries, and these usually ovulate alternately. What you describe is not uncommon; it's even a currently ongoing plot point in the webcomic Dumbing of Age. {The poster formerly known as 87.81.230.195} 90.217.47.60 (talk) 11:22, 17 November 2022 (UTC)

What has her doctor said about this? ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:11, 17 November 2022 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Uatchitodon's tragic status

Does anyone else think of it as being really tragic and depressing that the only known venomous reptile of the Triassic period is only known from teeth? CuddleKing1993 (talk) 19:54, 17 November 2022 (UTC)

"We don't answer requests for opinions". --174.89.144.126 (talk) 21:49, 17 November 2022 (UTC)

I'm confident that no one else thinks that. There were doubtless other venomous Triassic reptiles but if we don't have their teeth there's no way we could know they were venomous. We can't even be sure that Uatchitodon was venomous. Shantavira|^{feed me} 09:36, 18 November 2022 (UTC)

South American Ceratopsids, WHEN?!

Considering that We already have Saurolophine Hadrosaurs and Panoplosaurine Nodosaurs in South America, there just had to have been Ceratopsids in South America as well that coexisted with Abelisaurids, but we have not yet discovered any ceratopsid fossils for some unexplainable reason, why? CuddleKing1993 (talk) 20:00, 17 November 2022 (UTC)

Fossils are discovered by chance. Probably, nobody has been lucky so far. Ruslik_Zero 20:36, 17 November 2022 (UTC)

Even among megafauna for whom it is expected to be reasonable to find preserved fossils, we have only ever found a tiny fraction of likely species. Fossilisation is so unlikely that scientists estimate that less one-tenth of 1% of all the animal species that have ever lived have become fossils. Far fewer of them have been found. Which is to say that even forming a fossil is such a colossally rare event that most species are not even expected to have any fossil remains to even find, and given that we've only ever discovered a tiny portion OF THAT tiny portion, it is plainly unsurprising that any one particular species may have existed, and we have not yet found it. --Jayron32 13:14, 18 November 2022 (UTC)