Wikipedia:Reference desk/Archives/Science/2018 February 14

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February 14

To ride the storm

Could the R-101 disaster have been prevented by dumping ballast? Or would that not have made a difference, or caused even worse consequences? 2601:646:8E01:7E0B:0:0:0:64DA (talk) 11:10, 14 February 2018 (UTC)

I would suggest reading Len Deighton's Airshipwreck, a great coverage of just how unsafe large airships were, and in particular how hydrogen airships were so much safer than helium airships.

Airships have real problems with buoyancy control, with attitude control and with managing their response to changes in buoyancy. Helium is too expensive to vent carelessly, which makes it even harder. The R-101 also had every conceivable problem during construction.

Our article here gives the reason for the crash, but doesn't clearly mention it. Look at the notes on the original enquiry illustration of the final flightpath: the internal gas cells were leaking, leading to lifting gas running free within the external envelope. Just like a part-flooded ship (and the Herald of Free Enterprise) this destroys stability. In this case, the airship was running heavy and so needed a slight nose-up attitude to provide some dynamic lift. However she began to nose down, which increased her sink rate. This nose-down attitude let the lifting gas run to the tail, making the nose-down attitude even worse. Increasing speed would drive her downwards into the ground nose-first, reducing speed would lose the lift and make her settle into the ground belly-first.

Ballast was dumped. But there wasn't enough to make a difference. Also the ballast was dumped from the nose, in an attempt to make the nose rise, not simply to lighten the vessel. If some other ballast had been found and dumped, the vessel might even have raised further - but it wasn't the altitude which caused the flight into terrain, fundamentally it was the nose-down attitude - and there just wasn't enough ballast in the nose to solve that. Andy Dingley (talk) 11:36, 14 February 2018 (UTC)

You may be interested in the Report of the R101 Enquiry (March 1931). Alansplodge (talk) 17:31, 15 February 2018 (UTC)

Thanks, both of you! So, once the forward gas bags tore, there was literally nothing the crew could do to save the airship -- is that right? 2601:646:8E01:7E0B:0:0:0:64DA (talk) 02:15, 16 February 2018 (UTC)

Calder Hall

Hello! Is there any information provided here or elsewhere, what exactly the eponym of the site is? Was there a place called that way before, or was the name created exclusively for the power station? If so, what is the background?--Boczi (talk) 15:15, 14 February 2018 (UTC)

See Calder, Cumbria, Calder Bridge, Calder Abbey and River Calder, Cumbria. Gandalf61 (talk) 15:40, 14 February 2018 (UTC)

@Gandalf61: Thank you very much indeed! I had a swift look at those links, though I couldn't find any information on the second part of the term (Hall), unfortunately. Isn't that usually used for [former] mansions or similar?--Boczi (talk) 15:52, 14 February 2018 (UTC)

See here for the etymology of the word "hall". In place names, it usually denotes the location of what had been a central meeting house or chieftains home. It could have been an anglo-saxon chieftan, or a medieval manor house, or some such place, usually "The guy who's in charge's house". --Jayron32 16:03, 14 February 2018 (UTC)

... or "hall" can be used for any large enclosed space e.g. turbine hall, concert hall, exhibition hall. Gandalf61 (talk) 16:07, 14 February 2018 (UTC)

A Calder Hall near Calder Bridge was named in 1578 according to this. Mikenorton (talk) 19:38, 14 February 2018 (UTC)

Here is a record from the National Archives referring to a Calder Hall in Ponsonby. Mikenorton (talk) 19:53, 14 February 2018 (UTC)

Calder Abbey was founded even earlier - 1135 - according to Calder Abbey, a website managed by the Digital Humanities Institute affiliated with the University of Sheffield. Nimur (talk) 19:45, 14 February 2018 (UTC)

The ruins of Calder Abbey, and the later mansion built from part of them, are still in existence - but they are much further up the valley, beyond Calder Bridge. They cannot be the source of the Hall in Calder Hall, which is close to the mouth of the River Calder. This old map [1] does show a group of building labelled Calder Hall at roughly the northern end of what is now the nuclear site. Satellite views show an area on the north-eastern corner of the site which is undeveloped, with trees and what could be the remains of a garden, though I unable to spot anything which might be the ruins of a hall (this might be under the power plant, or hidden among trees).. Wymspen (talk) 20:36, 14 February 2018 (UTC)

Celery Seed

Some sources seem to indicate that the spice we call celery seed is not from celery (Apium graveolens) but is in fact seed from lovage (Levisticum officinale). Does anybody have a key for determining the species from the seed? I would rather not have to plant them because they are notoriously difficult to grow, and I have no plot of land. Heaviside glow (talk) 22:00, 14 February 2018 (UTC)

Most green grocers and supermarkets carry celery. You should be able to find some there; there's no need to grow your own. --Jayron32 02:03, 15 February 2018 (UTC)

That is the worst answer I have ever seen. You should look at the question again. Abductive (reasoning) 05:35, 15 February 2018 (UTC)

Google shows all manner of web pages describing how to grow celery. ←Baseball Bugs ^{What's up, Doc?} carrots→ 09:30, 15 February 2018 (UTC)

Both of you are completely missing the point of OP's question and should be ashamed of yourselves. Abductive (reasoning) 10:25, 15 February 2018 (UTC)

The OP seems to want to grow celery. ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:01, 15 February 2018 (UTC)

No they want to distinguish celery seeds from lovage seeds without having to grow anything. Nil Einne (talk) 22:59, 15 February 2018 (UTC)

Yes, I have such a key. Does it help? Henry^Flower 10:51, 15 February 2018 (UTC)

There are pictures here: File:Apium graveolens seeds.jpg and Apium graveolens Levisticum officinale Graeme Bartlett (talk) 11:30, 15 February 2018 (UTC)

I think you meant Levisticum officinale for the second one. The image appears to be from microscopy and the colours are a bit weird, so I'm not sure if it's that good for comparing to the Apium graveolens one. These might be better although they lack any size reference [2] [3] [4] Note that from reading these and the look of the images, I think what are generally sold as lovage seeds are actually botanically fruit. Similar to ajwain "seeds" which are often confused with lovage "seeds" per that article (with a reference). As per the earlier linked celery article, celery "seeds" are likewise fruit. Nil Einne (talk) 12:41, 15 February 2018 (UTC)

You are right. Struck wrong description. Graeme Bartlett (talk) 06:31, 16 February 2018 (UTC)

Thanks guys. Heaviside glow (talk) 20:57, 16 February 2018 (UTC)