Wikipedia:Reference desk/Archives/Science/2023 July 21

= July 21 =

In two bottles of different volume, both emptied up to a vacuum, is the pressure on the seal of each the same?
In two bottles of different volume, both emptied up to a vacuum, is the pressure on the seal of each the same? Bumptump (talk) 01:00, 21 July 2023 (UTC)


 * I'd think so. Thought experiment: what causes the presssure? What mechanism would increase or decrease said pressure based upon the contents (or absence thereof) of the bottles? --jpgordon&#x1d122;&#x1d106;&#x1D110;&#x1d107; 01:34, 21 July 2023 (UTC)


 * Assuming they're sitting next to each other, presumably each would experience the same air pressure. Are you thinking that the larger bottle would have more "suction" than the smaller one? ←Baseball Bugs What's up, Doc? carrots→ 03:15, 21 July 2023 (UTC)


 * I assume "emptied up to a vacuum" means that the sealed bottles each contain vacuum, and you're asking about the pressure exerted by the surrounding atmosphere. Then there are a couple of things to consider.  First, since the atmosphere has weight, the atmospheric pressure varies according to altitude, so if one of the bottles is placed higher, then the pressure on it will be reduced.  And second, it's not clear whether the original poster was asking about "pressure" in its proper technical sense (referring to the amount of force per unit area), or in the informal English sense where it just means a force that presses.  If the pressure in the technical sense is the same on both bottles (the air is at the same altitude and temperature), then the force on the larger seal will be larger in proportion to its area.
 * In any case, the volume of the bottles is irrelevant. --142.112.221.64 (talk) 05:19, 21 July 2023 (UTC)

Why does electrocution stop after a few seconds in a bug zapper?
I have observed that when an insect is electrocuted in a bug zapper, there are typically a few sparks or flashes of light. Sometimes the insect will catch on flame in a tiny fire, and the body will burn for a few seconds before stopping burning. The lights and flames stop after a few seconds, but the insect body often, instead of falling, remains in position still connecting two wires.

Given that the body is still in position connecting two wires, why is it that after a few seconds, sparks or flashes of light stop appearing, and any fire is extinguished? Does that mean that electricity is no longer flowing through the insect's body, and if so, why does the electricity stop flowing if the body is still connecting the two wires?

—SeekingAnswers (reply) 05:48, 21 July 2023 (UTC)
 * Maybe once their little carcasses are dried up, they can't conduct electricity? Abductive  (reasoning) 06:55, 21 July 2023 (UTC)
 * That is very likely the main cause - the corpse becomes non-conductive because it dries and burns up.
 * Another possibility (which, again, is less likely in my semi-informed opinion) is that the bug zapper needs time to recharge. A bug zapper is a discharge circuit where a capacitor is slowly charged when the circuit is open and then quickly discharged when the circuit is closed (by the poor insect). The charge time can be a couple of seconds while the discharge is much quicker (millisecond or lower) - but it’s hard to tell without a spec sheet of the electrical circuit, which I did not find in a quick online search.
 * Yes, discharge circuit is a redlink. Wikipedia does not have an article about everything, apparently. We have articles about Capacitor discharge ignition, cattle prod, bug zapper etc. but none of those give an electrical diagram. Tigraan Click here for my talk page ("private" contact) 09:24, 21 July 2023 (UTC)


 * I can't see how it could be the latter explanation, because all the bug zappers I've ever seen have virtually instantaneous "recovery" times, being able to zap multiple different insects seemingly simultaneously, and the dead insects often remain stuck between wires indefinitely without ever falling or reigniting even hours or days later.


 * So, a couple of additional questions arising from the first explanation: First, how exactly does electrocution cause drying: is it that electrocution generates heat, which causes the water to evaporate away into the air? And second, does that mean that organic tissue is nonconductive without water?


 * —SeekingAnswers (reply) 16:20, 21 July 2023 (UTC)

2023 Annular Eclipse...
... Of the sun due to take place in Oct. Of 2023. Just got this from a few news outlets. Some even have a map of the US, showing the path of the eclipse, and the time it'll take place. Is there info. On it here? Can this be used as a source? Thanks. 😺😺😺😺😘🥰 Nuclear Sergeant (talk) 11:45, 21 July 2023 (UTC)


 * See Solar eclipse of October 14, 2023.
 * Did you know: we have almost half a million articles tagged with "citation needed" somewhere in the text? I mean, if you're keen to find a source and have it used in an article, those are some of the ones that need sources. Solar eclipse, for instance, is tagged in two places. Card Zero  (talk) 11:50, 21 July 2023 (UTC)

Chokeberries
What may cause the tobacco-like smell of chokeberries and juice made of them? Are there, perhaps, some chemical compounds of same type in both the berries and tobacco plants? --2001:999:404:7509:5AE3:4A4:DD10:8B49 (talk) 13:15, 21 July 2023 (UTC)
 * Aronia has some info. Abductive  (reasoning) 00:00, 22 July 2023 (UTC)

Paired samples
For those interested (since there seems to be some slack there) – feel free to comment ideally within that thread. Best, Hildeoc (talk) 13:44, 21 July 2023 (UTC)