Science desk
< December 22	<< Nov \| December \| Jan >>	December 24 >

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

December 23

Sweet Heavy water

According to this youtube video: [ https://www.youtube.com/watch?v=MXHVqId0MQc ] it appears that heavy water (deuterium oxide, ²
H
₂O) tastes sweet. Our article on Heavy water has two citations[1][2] that contradict each other on this. I am trying to figure out why the taste would be different, given that different isotopes typically have the same chemical properties. If we could find a reliable source, I could expand the heavy water article a bit, but of course a youtube video isn't good enough. --Guy Macon (talk) 12:46, 23 December 2016 (UTC)[reply]

Not quite the same chemical properties -- heavy water forms a slightly stronger hydrogen bond than regular water. 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 12:56, 23 December 2016 (UTC)[reply]

For any element heavier than hydrogen, the chemical differences between isotopes is so subtle as to be basically non-existent. But Deuterium has twice the mass of ¹H, which makes an observable difference. -Arch dude (talk) 21:18, 24 December 2016 (UTC)[reply]

Exactly. From Advanced Inorganic Chemistry by Cotton and Wilkinson p.216: "For most elements a change of one or several mass units in the nucleus is such a small percentage change that, owing to the very indirect way in which nuclear mass can effect chemical behavior, the chemical differences between isotopes are not detectable. However, for the lightest elements, B, C, N and especially H, reactions involving different isotopes do proceed at slightly but measurably different rates." The name for this is the kinetic isotope effect, however our article is more likely to leave you confused than enlightened, and I would instead suggest an inorganic chemistry text; most should cover the concept. (This does not establish a taste difference between H2O and D2O, but only provides a possible explanation if there is a taste difference. Also, the above linked ScienceDirect article appears to be about heavy water affecting the taste of things dissolved in it rather than the taste of heavy water itself, though the avoidance behavior that the article mentions was observed in previous studies must have some cause.)--Wikimedes (talk) 19:56, 28 December 2016 (UTC)[reply]

Juicy Fruit (not the snack)

What was the gas codenamed "Juicy Fruit" which they used in the Vietnam War (mentioned in The Rescue of Streetcar 304 by Kenny Wayne Fields)? 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 12:48, 23 December 2016 (UTC)[reply]

Sounds like Agent Orange to me.--TammyMoet (talk) 13:14, 23 December 2016 (UTC)[reply]

The book is referring to a sleeping gas, which is clearly not agent orange. An officer tells the pilot to use his oxygen mask because they will be dropping "juicy fruit" to knock out the enemy for about 15 minutes. So, if true, it is referring to a knockout gas used in Laos. 209.149.113.5 (talk) 14:14, 23 December 2016 (UTC)[reply]

There's really no such useful thing as "sleeping gas". Physiologically it's too difficult a problem, to randomly spread such a gas across a variety of targets and give each one a dose adequate for anaesthesia, but not fatal. Even in a relatively confined and controlled space like the 2002 Moscow theater hostage crisis, the chemical agent used killed more of the hostages than the kidnappers did. Andy Dingley (talk) 14:58, 23 December 2016 (UTC)[reply]

Now that it is clear that it was referring to CS gas, it appears that the book meant that the combatants would be "disabled" rather than "knocked out." 209.149.113.5 (talk) 15:18, 23 December 2016 (UTC)[reply]

This book (Cheating Death: Combat Air Rescues in Vietnam and Laos by George J. Marrett) identifies "Juicy Fruit" as "CBU-19", a riot control agent. This site (probably not a reliable source) identifies "CBU-19" as CS gas, although other riot control agents were used in Vietnam. Tevildo (talk) 14:39, 23 December 2016 (UTC)[reply]

It makes sense to call cs gas "juicy" as it makes so much liquid come out of everyone's nose. 209.149.113.5 (talk) 15:12, 23 December 2016 (UTC)[reply]

The book "Leave No Man Behind: The Saga of Combat Search and Rescue" states that CS gas from the CBU-19 bomb was codenamed "Juicy Fruit." 209.149.113.5 (talk) 15:15, 23 December 2016 (UTC)[reply]

Thanks, all! So, "Juicy Fruit" was just ordinary tear gas like the stuff that the riot police use? 2601:646:8E01:7E0B:F88D:DE34:7772:8E5B (talk) 03:27, 24 December 2016 (UTC)[reply]