Wikipedia:Reference desk/Archives/Science/2021 June 19

Science desk
< June 18	<< May | June | Jul >>	June 20 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is a transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

June 19

Which science book had this metaphor about atoms

In some popular science book I read long ago, there was a passage that went something like this: If an atom was the size of the ceiling of the Sistene Chapel, then the nucleus of the atom would be the size of of a grain of sand, in the center of the ceiling, and an electron would be the size of a speck of dust, at the edge of the ceiling. I'm trying to identify that book and that passage. Thanks if anyone can help.

But you just can compare the sizes of an atom, nucleus and electron. Ruslik_Zero 20:40, 19 June 2021 (UTC)

As was done in this forum discussion [1]. 80.44.95.69 (talk) 20:45, 19 June 2021 (UTC)

I'm pretty sure the same comparison has been made using the dome of St. Paul's Cathedral, and possibly also the Albert Hall. Since famous public buildings with roughly comparable open volumes are found throughout the world, it's probably a recurrent theme that gets tailored for the particular national readership that's being addressed. Compiling a list of them might be an interesting project. {The poster formerly known as 87.981.230.195} 2.122.59.177 (talk) 21:26, 19 June 2021 (UTC)

This is problematic, since an electron around a nucleus takes the form of a standing wave, and not a single point (like a speck of dust). See atomic orbital. What would be a better description would be to describe the scale as a grain of sand in the center for the nucleus, surrounded by a "cloud" that reaches roughly to the edge of the ceiling for the electron (assuming 1 electron, and we are discussing a hydrogen-like atom. Note that I haven't actually done the math to see if that scale is accurate, but it's still a better description than any that describes an electron around an atom as a point charge particle. --OuroborosCobra (talk) 23:22, 20 June 2021 (UTC)

Hi, I'm the OP. Thanks all for your comment and options and opinions - as I posted in the original question, I'm trying to identify the book, and find the quotation or book section. I'm not actually trying to do the math. However, somebody did the math in a really, really interesting way that some of you may find interesting: https://www.ericpsmith.scot/a-grain-of-sand-in-st-pauls-cathedral

We aren’t really going to be able to answer this question to your satisfaction, sadly. It’s not that you have a bad question per se, but the sheer number of textbooks out there makes it not feasible. This could be in a chemistry textbook, physics, general science, even earth science, and many others. Beyond the topics, at any one time, there are untold numbers of different chemistry textbooks in use. I don’t think there exists a database for us to search for something like this. I’m sorry that we can’t help anymore. You could try searching using Google Books, but we aren’t going to be able to do any better than it could. -OuroborosCobra (talk) 04:58, 24 June 2021 (UTC)

Actually, I think I can make a decent educated guess as to what the book in question might be. OP, does The Tao of Physics by Fritjof Capra sound familiar? The reason why I ask is that the simile you describe is rather close to one which is utilized in the film Mindwalk--see here. Now Mindwalk is itself meant to be an exploration of Capra's works up until that time (particularly his treatment of Systems Theory, The Turning Point), and is written in the style of Galileo's Discourses and Mathematical Demonstrations Relating to Two New Sciences, with each of the three principle parts speaking to different approaches to the titular subject matter (and to some extent, to different phases of the author's own work through on the overarching topics). So I would expect almost any imagery utilized in the prose of that script to harken back to one of his works. I've read The Turning Point and several of Capra's other works in their entirety, and I don't recall seeing that particular comparison--actually, I am kind of surprised I had remembered the quote in Mindwalk since I only saw the film the once, decades ago. But Capra wrote a popular science book some years before The Turning Point: the afore-mentioned The Tao of Physics, which I have only ever read small snippets from. Given the number of convergent factors above, and the additional fact that Capra demonstrates a certain fascination with the High Renaissance in other of his books, I think you might want to look there: it all seems to add up, though I can't say as I've previously read the exact language you are hunting for. Snow ^{let's rap} 13:23, 25 June 2021 (UTC)

I've read The Tao of Physics and I'm also familiar with the analogy, though I couldn't put my finger on it until now. I think you may be right. But, as others have said, the analogy may have been used by multiple authors over the years. nagualdesign 01:12, 27 June 2021 (UTC)

Getting rid of ants

What's a good deterrent for ants in the house other than sodium bicarbonate? I'm looking for something that can be smeared on walls since they will go up the walls to bypass thresholds made of soda. Ideally something that's not folk medicine, I tried peppermint, lemons and vinegar and all it does is attract them. Tea tree oil seems to work based on one attempt but I'm wary of pasting the whole house in case it just ends up giving them more food. I'm not sure which ant species it is, it's the garden variety here in Croatia (black/dark brown, about 0.5-1 cm in length I think, could be this one). 93.140.20.45 (talk) 20:31, 19 June 2021 (UTC)

In the UK it's common to use one of several proprietary brands of insecticide "ant powder." These are usually very fine white powders, resembling talcum powder, that taste good to ants (and other insects) but which are a slow poison to them. The powder is puffed from its container on to the bases of walls or other areas where ants are frequently seen walking, into cracks and holes where they enter the building, and so-on: if the site of the nest is known, the powder can be applied directly to it. The ants collect and take this 'food' back into their nests, and after a while the whole colony dies.

The one I'm now holding can be safely used indoors, although one should avoid inhaling it or contaminating food preparation surfaces. If you don't have local hardware stores or similar that sell such products, web-search for "ant killer" or "ant powder."

It may be that you wish not to use such 'artificial' products. If so, hopefully others can suggest more 'natural' methods. {The poster formerly known as 87.81.230.195} 2.122.59.177 (talk) 22:00, 19 June 2021 (UTC)

Diatomaceous earth is non-toxic (but be careful not to inhale dust); it works for me. Also, after mopping floors, rinse with borax solution. 2603:6081:1C00:1187:398F:C182:48C8:BFA5 (talk) 22:22, 19 June 2021 (UTC)

Ants are a persistent issue in Australian houses. We use a proprietary formulation called AntRid, which is a mixture of sugary water and a slow acting poison. https://www.henkel.com.au/brands-and-businesses/ant-rid-664072 I rarely have to use it twice. Greglocock (talk) 22:58, 19 June 2021 (UTC)

That poison is borax, which is sort of natural. What I find works, is to find the hole that they come inside and fill it up with a plaster type wall filler or silicone. With ant powder I find that ants will not walk on it, but it can't really be used on a vertical surface, and I would not want to use it inside the house. If you use ant rid, put it near where they enter, so that they will find it quick. Graeme Bartlett (talk) 10:17, 20 June 2021 (UTC)

One has to be tenacious about it for a while, especially if you live in older housing with many gaps, but consistently identifying and eliminating their entry points with silicone or other fillers is likely to give the best long-term results. I agree that Borax based ant poisons are effective, but I believe they may be hard or impossible to obtain in the EU due to restrictions placed on borates as a result of concerns that ingestion (in high doses) may have an impact on reproductive health. Dragons flight (talk) 08:32, 23 June 2021 (UTC)

Thanks for the ideas, I'll look into those and keep an eye on this discussion. I'm kind of not happy with the "natural" solutions I've tried so far, since the ants just seem to enjoy it and tell their friends, and insecticides they could carry on their bodies to our kitchen table, that wouldn't be healthy. Mainly the problem with the ants is that they created a nest probably in the central drain of our flat roof and fed on the bugs eating weeds that grew there, since we haven't been up there for a while. Now that we've plucked those weeds they lost their food source and keep entering the house. I'm hoping they'll give up eventually since the house is clean. 93.140.20.45 (talk) 23:14, 19 June 2021 (UTC)

Powdered cinnamon works as a deterrent, at least on pavement ants in the US. 2600:1702:2670:B530:55B1:561E:5D15:8933 (talk) 18:41, 21 June 2021 (UTC)

I have also heard that artificial sweetener can work, as the ants love it, but they starve. I do not really know if this works though. Graeme Bartlett (talk) 00:07, 22 June 2021 (UTC)

That mechanism is somewhat apocryphal: the toxicity of artificial sweeteners to disparate ant species has been tested empirically on a handful of occasions (one of those cases of research chasing the rumor mill, I think): the outcomes have been all over the place, with some species shrugging it off ([2]), and others apparently being quite vulnerable to it (https://academic.oup.com/jee/article-abstract/110/2/593/3063342?redirectedFrom=fulltext). However, crucially it does not seem to be the case that ants are gorging themselves on the sweetners and then failing to take in sufficient calories to live. Rather it seems to be the case that some of the sweetners are just directly toxic to some ant species. The notion that they are starving from obsessive consumption of the sweetners seems to be an element that was added by folk science: this is actually a method that other commercial ant baits have legitimately used, I believe, so someone with just enough scientific understanding to conjecture (but not enough scientific understanding to recognize that you don't share shot in the dark explanations without testing your hypothesis) seems to have conjoined this mechanism of known pesticides with what they knew of how artificial sweetners work. And of course, the resulting story is just complex and fascinating enough that it takes on a life of its own once ejected into the urban myth environment. Anyway, long story short--if the OP's aim is primarily to discourage ants from entering their abode, the last thing they want to do is put out any product that emulates the chemical structure of complex sugars: it will only attract more of them, with an extremely small chance that they are amongst the species that are vulnerable to its toxic effects. Snow ^{let's rap} 01:44, 26 June 2021 (UTC)