Wikipedia:Reference desk/Archives/Miscellaneous/2010 January 23

= January 23 =

Visible ink, invisible when photocopied
I remember, many years ago, using a pen that enabled us to write openly on a master document (e.g. MASTER) and photocopy from it without that writing showing up on the copies. Googling for "invisible photocopy pen" and the like doesn't work: I get sites about ink that is invisible under normal circumstances but shows up in photocopies, which is the opposite of what I want. Any ideas what this sort of pen or ink is called, and where they are for sale? Thanks. BrainyBabe (talk) 09:14, 23 January 2010 (UTC)
 * Many years ago, ordinary light blue ink often did not show up on photocopies, but the technology has been much improved since then. Ghmyrtle (talk) 09:37, 23 January 2010 (UTC)
 * Non-photo blue? 80.219.8.3 (talk) 09:46, 23 January 2010 (UTC)
 * You can always write "Master if [colour x] " with a [colour x] pen, then black and white photocopies will not be confused for the master... Aaadddaaammm (talk) 10:59, 23 January 2010 (UTC)
 * Standards Australia used to do something like that (I don't know if they still do). When you bought a printed copy of a standard from them, it was stamped with "". Mitch Ames (talk) 03:49, 24 January 2010 (UTC)
 * I spent many hours of my youth playing music that said If this writing is not in red, this is an illegal photocopy. It was always black. 86.179.150.105 (talk) 19:34, 25 January 2010 (UTC)

Highlighter pens (the yellow colour) usually don't show up in photo-copies. Also this yahoo-answers suggests a 'non-repro' blue pens (http://www.shoplet.com/office/db/PIL16002.html) (source: http://uk.answers.yahoo.com/question/index?qid=20081205040756AAJ2yQ3). ny156uk (talk) 15:58, 23 January 2010 (UTC)
 * My office use Yellow Highlighters too - doesn't show when photocopied... Gazhiley (talk) 13:34, 27 January 2010 (UTC)


 * The older black and white only copiers usually had one colour they couldn't detect very well (often red, but sometimes blue). I occasionally found my hand-written notes would have disappeared.  Like Mitch hints at above, you could also get a coloured ink-stamp that said "Original" in the colour the copier couldn't see; that way any copies were not marked original and could in theory have been altered without authorisation (very important in security-consious industries like defence).  Astronaut (talk) 05:11, 25 January 2010 (UTC)
 * Unless the person doing the altering had the same stamp... Nil Einne (talk) 10:57, 28 January 2010 (UTC)

Thanks all, appreciated. BrainyBabe (talk) 22:46, 27 January 2010 (UTC)

Tivo To VHS
I'm trying to get something from a friend's Tivo--specifically, an episode of YRU-Up that I hosted--to a VHS tape. My friend says that we need something called an SV cable, but Google talks of many different kinds. So for those who are Tivo savvy: how can I get a program into a tape and what sort of SV cable would I need? Thank you. Tuesday42 (talk) 20:07, 23 January 2010 (UTC)
 * Does your friend mean an S-Video cable? If you have a composite video cable lying around you can use that, as well. All you need is something to connect one of the secondary (i.e. not used for TV) outputs to a VCR recording on its input channel - usually 3 or 4. This is assuming the Tivo has two tuners - i.e. the capability to output a live program to the TV and the recorded program to the VCR. In a worst-case scenario, if the Tivo has a coaxial cable output and both your VCR and your TV have the same input, you can rig them together with two lengths of coaxial cable, play the recording as if you were watching it, and record. Xenon54 / talk / 20:49, 23 January 2010 (UTC)
 * So would a generic S-Video cable work or is there a specific kind I would need? Tuesday42 (talk) 23:55, 23 January 2010 (UTC)
 * Any cable will provide an adequate recording - just make sure it's long enough. (I once had the misfortune of buying a $35 HDMI cable that was six inches too short! Fortunately, I think S-Video cables are only that expensive when you get to 20 feet or so.) Xenon54 / talk / 00:01, 24 January 2010 (UTC)
 * My Tivo (in the UK) uses SCART cables. To write to VHS, you connect a SCART to the Tivo's VHS out connector and connect the other end to the recorder.  Then start the recorder and select "Save to VHS".  --Phil Holmes (talk) 22:20, 23 January 2010 (UTC)
 * Thanks for the info, but I live in the U.S., so SCART cables are out. Tuesday42 (talk) 23:55, 23 January 2010 (UTC)
 * Aparantly, SCART cables are called EIA Multiports in the US. 89.242.94.72 (talk) 23:42, 24 January 2010 (UTC)


 * If the back of your friend's Tivo looks like this image from the Tivo article, you would need either the above mentioned S-video cable (if your VCR has an S-video input) or a set of video copying cables with 3 RCA connectors at one end (red, white and yellow - just like in this image) and probably the same at the other end for your VCR. Once you have connected the Tivo output to the VCR input and got the VCR on the correct input source, it is a simple matter to hit record on the VCR when you hit play on the Tivo.  Astronaut (talk) 04:57, 25 January 2010 (UTC)

School day start time
This article got me thinking about why school days start at the time they do. The article is about children suffering through lack of sleep, and mentions that, in the USA, children who start school later tend to perform better. It goes on to say that "obstacles against later start times are numerous", but doesn't say what these obstacles might be. So my question is, what debates are there around what time the school day should begin? I'm not interested in when the school day starts in any particular country, just in what the pros and cons are to starting earlier vs. starting later. I was surprised to read that 85% of public high schools in America start their day before 8.15am. That seems far too early to me, and I can't imagine why anyone would argue in favour of such an early start time. The only arguments I can think of in favour are (a) more daylight after school in the winter months and (b) more time to do after-school activities, but these seem heavily outweighed by the arguments put forward in the article in favour of a later start time. Thanks. --Richardrj talkemail 20:16, 23 January 2010 (UTC)


 * Early starts are convenient for working parents. I'm not in the least surprised that later starts appear to be associated with better performance. DuncanHill (talk) 20:25, 23 January 2010 (UTC)


 * A few years ago, there was some talk here locally about changing start times for schools. Roughly speaking, schools here start with a schedule something like this:
 * High Schools run from 7:15-2:15
 * Middle Schools run from 7:45-2:45
 * Elementary Schools run from 8:15-3:15
 * I've made those numbers up, but they capture the general idea of the schedule here in Raleigh, North Carolina. From my memory of the discussion, the idea was to "flip-flop" the schedule, so that Elementary schools would run from 7:15-2:15 and High Schools would run from 8:15-3:15.  The reasons cited in support of the move were pedagogical/psychological.  Apparently several studies had been done that found that older children reached "peak performance" later in the day than younger children; that is from a pedeagogical perspective it made more sense to have younger kids in school earlier and older kids in school later, since it better matched their own diurnal schedules.  The opposition to this plan was based around non-educational factors, such as 1) after school activities (for example, a sports team playing an "away" game would miss more class time, since they would still need to leave to travel) 2) families depend on having the older children home FIRST to watch after the younger children, and the proposed changes would have left lots of elementary-aged children home without supervision for some time.  3) High school students often have after-school jobs, and such a change in schedule would affect that.  I distinctly remember #2 being the biggest factor in deciding NOT to enact a later start time for HS students.  -- Jayron  32  21:28, 23 January 2010 (UTC)


 * Hmm ... an interesting article. I was surprised to read about how early some schools start in the US. Around 8:45 a.m. would be the average starting time for UK schools.  Of course, an earlier start doesn't have to mean less sleep, but late bedtimes are becoming a cultural norm everywhere. As the article says: Overscheduling of activities, homework, lax bedtimes, television sets and mobile phones in the bedroom all contribute [to lack of sleep]. So does guilt; home from work after dark, ­parents want time with the children and are ­reluctant to order them to bed.    D b f i r s   21:34, 23 January 2010 (UTC)
 * (E/C, not a biggy) I don't think the Grauniad article mentioned the UK example. In short, they started school an hour later. given the average teaching in a day is about 5 hours, this cut teaching time by a fifth. There are plenty of reasons why they didn't extend the day, eg. abov. This lead many people to question whether the gain in "productivity" (undisputed in itself) was worth it. Also, people here are mindful of the continent, and French and German schools start earlier, in most cases. I believe German schools start at least an hour earlier, if not more. (An appeal to popularity, as it were.) - Jarry1250 [Humorous? Discuss.] 21:40, 23 January 2010 (UTC)
 * School in Germany, at least for younger children, begins between 7:30 and 8:15 (the majority are closer to the later end of that range) and can end as early as 12:00, though it's usually closer to 12:30 - 13:00 and definitely no later than 13:30. For higher grades, there are usually "afternoon lessons" that extend past 13:30, sometimes well in the afternoon. This depends on the school; if that is the case then an in-school lunch break, a foreign concept to German students who are used to going home for lunch, may be provided.Xenon54 / talk / 21:53, 23 January 2010 (UTC)
 * My high school (early-mid '90s) began at 7:30, with the middle school having a later start and the elementary school the latest start. The idea was to ensure the oldest kids got home first so they would already be there when the youngest kids got home. I had the misfortune of having math class first period one year and fell asleep in class just about every day. -- Mwalcoff (talk) 23:01, 23 January 2010 (UTC)
 * Wow looking at all these times make me feel glad that in New Zealand schools (at least for me, but I'm not aware of much variation) start at around 8:30 for both primary and secondary schools. --antilivedT 23:46, 23 January 2010 (UTC)
 * Many American students use school buses, so they have to stagger the start times unless it's a really tiny school district. If everyone came to school at the same time, they'd have to buy three times as many buses and hire three times as many drivers. -- Mwalcoff (talk) 00:35, 24 January 2010 (UTC)
 * A later start would be better in almost every way. Unfortunately you can't get it to happen, because of football.  Schools start early to allow football practice after school &mdash; slightly oversimplified, maybe, but not much.
 * I would like to see competitive sport very much de-emphasized in secondary school. This is very different from the question of physical fitness, which if anything needs more emphasis.  But physical fitness is best attained through individual activity, not team sport. --Trovatore (talk) 04:04, 24 January 2010 (UTC)

Two comments. (1) Someone above mentioned convenience for the parents, but what's convenient for the parents will vary depending on typical working hours in the particular city (and perhaps on how far the parents typically have to commute). And (2) In the 5 different schools I attended in two different provinces of Canada, the start time was invariably 9 am or within 10 minutes of that. When I got to university, the earliest lectures were 8:30, but that time slot was relatively little used and it was often possible to start the day at 9:30 or later. --Anonymous, 05:02 UTC, January 24, 2010.


 * The school I attended typically started at 9am and finished around 3:30 or 4 pm. That still left me with a couple of hours after school with no parental supervision.  It leaves me wondering how an 8am or earlier start is more convenient for parents if the kids are kicking around town most of the afternoon til their parents return from work at 5 or 6pm?  Astronaut (talk) 04:38, 25 January 2010 (UTC)
 * Well I guess it goes back to the typical start time of a working day. As the anon said above these will vary, but in general working days start between 8am and 9am.    The later the school day starts, the harder it becomes for the parent to get to work on time. --Richardrj talkemail 06:21, 25 January 2010 (UTC)
 * That's why they send the high-school kids home so early -- so there's more likely to be an older sibling at home when the younger kids get there. -- Mwalcoff (talk) 00:48, 26 January 2010 (UTC)