Wikipedia:Reference desk/Archives/Science/2016 May 7

Science desk
< May 6	<< Apr | May | Jun >>	May 8 >

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.

May 7

Mechanisms and or Functionalities sought

Apparently this exists in the game. If so,

1. What's the mechanism(s)/functionality(s)
2. How it does what it is suppose to do?

Apostle (talk) 09:45, 7 May 2016 (UTC)

When I googled world of warplanes ufo mechanism, I came to this site. Take note of the date (April 1) and the comment "Thanks for laughing along with us on April 1st!" under the picture and see if you can come to any conclusions on your own. In the future, questions about games should probably go in the Entertainment desk. Matt Deres (talk) 12:16, 7 May 2016 (UTC)

For proposed actual use of flying saucers in the military, see Avrocar. StuRat (talk) 15:09, 7 May 2016 (UTC)

Unsatisfying. Thank you (both) anyway -- Apostle (talk) 18:40, 7 May 2016 (UTC)

Place with the largest observable part of the other celestial hemisphere

In what place on Earth the largest part of the other celestial hemisphere could be observed at night (such as in northern celestial hemisphere with the largest number of southern hemisphere objects or vice versa)? Thanks.--93.174.25.12 (talk) 13:47, 7 May 2016 (UTC)

The closer you get to the equator, the more of the "other" celestial hemisphere you should be able to see. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:55, 7 May 2016 (UTC)

A tall vantage point should help as well. Combining the two, Chimborazo should be a good choice. Kilimanjaro wouldn't be a bad choice either. --82.164.37.199 (talk) 14:34, 7 May 2016 (UTC)

preheating oven pointless?

I notice that to put food in I have to basically open the door all the way and for at least 2 or 3 seconds...all the hot air is let out..if google "preheating oven pointless" a lot comes up to suggest it's true....true??68.48.241.158 (talk) 16:36, 7 May 2016 (UTC)

No, definitely not pointless because the thermal capacity of the heating elements and the metal structure of the oven far exceeds the thermal capacity of the air released on opening. The cooler air that flows in is quickly heated to the temperature of the metal that surrounds it. Dbfirs 16:40, 7 May 2016 (UTC)

what you say is scientifically true, of course...I wonder about the practical difference...is there that much of a significant practical difference considering how quickly modern ovens heat up...??68.48.241.158 (talk) 16:51, 7 May 2016 (UTC)

Yes, I was thinking of older ovens with a high thermal capacity. If the oven heats up to the required temperature in a few seconds, then pre-heating is indeed almost pointless, but only my small halogen oven does this. Dbfirs 16:58, 7 May 2016 (UTC)

well, seems like it get to 400F in 6 or 7 minutes...to 300F in 4 or 5 minutes...68.48.241.158 (talk) 17:05, 7 May 2016 (UTC)

It also depends on what you are using your oven for. Baking often needs a constant even temperature for a relatively short time, so pre-heating is important. If you are roasting a joint then you can just add five minutes to your cooking time instead of pre-heating. Dbfirs 17:09, 7 May 2016 (UTC)

Preheating where needed is probably not mostly about times or temperatures. These are factors, but the biggest one is probably that during heating the elements or burners give of a lot of infrared which may not be want you want. BTW, this was discussed before on the RD, see Wikipedia:Reference desk/Archives/Science/2009 October 9#Why preheat the oven?

You gave figures for how long it takes to reach the desired temperature from cold, but not how long it takes to return to the temperature after opening (if the elements even come on again). If it's 1 minutes vs 4 minutes this is still a very big difference if the total time is short. Note that if you've been using an oven enough with a variety of different things, it's not that hard to see how big a difference having the elements on as well as not preheating can make.

Also if you read some of the results from your search, you'll likely find people with similar comments e.g. [1] [2] [3]. There are a few who appear to be speaking from actual experience (rather than simply theoretical which to be frank is likely too spherical cow to be useful) e.g. [4] (and some of the comments in the discussions) but it's not always clear what the specific experience involves.

I'm sure people preheat in a lot of cases where it's not really particularly useful. And I'm sure preheating with modern ovens and smaller ones is often less important than with older ones and larger ones. But this is different from saying preheating is always useless (other than for time saving if you remember to preheat during prep) with most resonable size home ovens.

Nil Einne (talk) 20:39, 7 May 2016 (UTC)

I imagine for things like roast potatoes that bringing them slowly up to temperature in a bath of cold duck fat would result in a quite different outcome to dropping them into hot fat. Similarly with roast chicken, the skin would dry rather than crisp. For stews and the like I doubt it makes much odds. Greglocock (talk) 00:01, 8 May 2016 (UTC)

Its simply a timing issue, because recipies need to set a reliable time frame to cook or roast something properly. For one oven may need 15 minutes and another only 5 minutes to heat up, you can not include that. With some cooking experience you can estimate and include the preheating phase with your oven and very likely save some time. --Kharon (talk) 00:53, 8 May 2016 (UTC)