The upside-down watch mystery

[@ttookkyyoo]

I can't believe nobody made the 'Australia' joke just because the clock was upside down

[@LelouchVee]

ɹǝɥʇᴉǝ ʇᴉ ǝʌǝᴉlǝq ʇ,uɐɔ I

[@scottcampbell96]

They were afraid of the klaxon.

[@PrestonFrankel]

@@scottcampbell96 Blue whale!

[@DadgeCity]

These guys are 5heads, not 0.5heads

[@nirmalsuresh7964]

That takes a lot of self control

[@fademejake]

In next weeks episode Tom will pose a question involving a slide rule and the symbols on a commodore 64 keyboard and truly confuse the rest of the panel.

[@WyvernYT]

I would be the correct panelist for that; I've used both of those things.

[@zumabbar]

@@WyvernYT time to go to bed, grandpa

[@mulgerbill]

The week after that he'll teach them to play minesweeper in Win98 via the command line

[@thomaswhite3059]

"CALL ME OLD WILL YOU? I'LL SHOW YOU!"

[@nivalshade]

BTW Korean here. Koreas don't use half time anymore. North Korea used UTC+8:30 since August 15th 2015(Korean independence day) while South Korea uses UTC+09:00. In May 5th 2018, North Korea returned to UTC+09:00.

[@nivalshade]

en.m.wikipedia.org/wiki/Time_in_North_Korea

[@KirkWaiblinger]

Taha's answer of 6.5 hours is nearly just as valid. Rotating it once will advance the time 5.5 hours, and then rotating it again will advance the time 6.5 hours. Considering a full rotation most get the clock back where it started, the two times must add to 12, so there has to be a pair of answers. Some other thoughts I found interesting: the "nudging the hour hand" refers to the fact that you need to imagine the hour hand is 30 minutes back from where it is. This is due to the fact that clocks do not have continuous rotational symmetry. There are 11 times a day that have both hands pointing in the same direction. 12:00, 1:(60/11 minutes), 2:(2*60/11) minutes, etc. So, the clock hands have rotational symmetry every 11th of full turn. However, half a turn is not expressable as an integer number of 11ths of a turn, so, really an upside down clock is not a valid clock at all. If you also have a clock where the hours are marked (just the positions matter; ignore the values of the numbers), then the hour markings themselves have symmetry of a 12th of a turn, which is incompatible with the hand symmetry of 11th of a turn, therefore, there is only one valid marked clock orientation and that is right-side up. The obvious way to see the problem with half turns is to note that a clock that reads 1200 flips to have both hands facing down. But, wait, 30 minutes past the hour means that the hour hand should be between two hours too, not pointing directly at hour 6. While at first glance you might want to read both hands down as 630, the system Tom is referring to would actually read that as 530 (the rule being to nudge the hour hand back by half an hour, or, equivalently, if the minute hand is 30 or greater, read one hour less). Well, I suppose that's a fine system if you really want your watch flipping to work at 5.5 hour difference. But, you could also consider the hour hand to be the source of truth, which would give you 6 hour offset, and then just move the minute hand 30 minutes (just imagine it's pointing the opposite way). (So, when both hands are pointing down, pretend the minute hand is pointing up, and read the clock simply as 6:00). This has the appealing property that a half turn is half of 12 hours, both times you rotate the clock. Moral of the story: clock rotating is not as clean as you might expect going into it, mostly due to the redundant minute hand. If we used a clock with just an hour hand, you could rotate to your heart's desire. Edit: also, there absolutely are 24 hour watches and so Sabrina's answer of 12 hours could also be valid too.

[@random832]

Both rotations obviously do the same thing, they advance the hour hand by 6 hours and the minute hand by 30 minutes. When you've got the watch upside down, when the minute hand is at the "top" of the clock the hour hand will be in a halfway position, so it's not *really* fully valid for *any* time zone, just sort of close enough for either a 5.5 or 6.5 hour time difference.

[@KirkWaiblinger]

@@random832 yes

[@mutantgeralt]

This guy clocks

[@Naf623]

I used to have a backwards clock. Agter a while it becomes just as automatic to tell the time on it; but its hilarious seeing how people react when they come to visit and try to see what time it is.

[@Lyarrah]

I've got one too, it's one of my favorite things I own, but admittedly now I take a minute to translate real ones.

[@mikefurlong8025]

I'm trying to figure out whether that's evil, or pure genius! 😃

[@rageagainstthebath]

I own a binary watch and got fluent in binary up to 60. A great habit for electronic engineers

[@PouLS]

An anti-clockwise clock

[@JACKHARRINGTON]

Honestly, I prefer counterclockwise to clockwise. And in my own house, I'd have a clock that swaps the length of the hands because having the longer unit with the shorter hand and the shorter unit with the longer hand is NOT compatible with the intuition I have for maths/physics.

[@AndrewHansford]

Bonus question: What was the date that woman found in the arrivals lounge? India is always UTC+5.5. The time at Heathrow is UTC+0 for ~5 months of the year and UTC+1 for about ~7 months of the year. So the trick only works when the UK is on GMT between the last weekend in October and the last weekend in March. If you would like the riddle to work year round you can use Keflavik Airport in Iceland which is on UTC+0 all year. This also means Myanmar (UTC+6.5) works as and answer for Heathrow for more of the year then does India.

[@harrodharrod5239]

The fact Sabrina's camera is mirrored and the clock face is weird on its own makes this so much funnier.

[@bazzers]

Totally. The Roman numerals -- radial, top-out orientation on the watch face, with the individual numerals symmetric on horizontal reflection -- helped make it much more confusable so even funnier. Was staring at a pause of her watch face for a little bit until I burst out laughing, realizing the horizontal mirroring.

[@literallyjustgrass]

I was just staring at that watch going "why the hell is there an 8 and a 4 on there"

[@Wecoc1]

I had a teacher that always wore an upside-down watch so when holding the book the kids would know what time it was just by looking at it 😅

[@stevencowan37]

I'm pleasantly surprised that Tom can discuss timezones after his traumatic experience with them in the past...

[@munjee2]

Being from Pakistan, I Knew it would be India because as a kid I wanted to watch the show "young justice" but I always missed most of it, even when I rushed home, because it aired at "2:30" India but "2:00" PST, so I just assumed every country just went half an hour ahead from the last

[@Mr.Unacceptable]

PST is pacific standard time. Do you also use this acronym for a Pakistani time zone?

[@munjee2]

@@Mr.Unacceptable not sure if its official but TV channels called it "Pakistan Standard time" which I always found weird sincewe only have the one time zone

[@ClementinesmWTF]

You can actually use the mental nudging trick to also make it work for *Myanmar (not Korea) and Australia for UTC+6:30 (and for anyone wondering, the other country with UTC+5:30 is Sri Lanka; they do it to keep in lockstep with their largest trading partner and closest neighbor, similar to Samoa moving the International Date Line to be closer to New Zealand/Australia economically)

[@costie31]

A while back I designed Escape Rooms - one of them had a puzzle with wall analog watches in witch they had to use the time as a for digit code. You could not belive the struggle they had to get to the correct answer- no mather the age. Thank you for the ”brain candy” 🧠

[@Milamberinx]

Is English a second language to you? Or is there somewhere that says "wall analog watches" instead of "clocks" in English? Not being sarcastic, just interested.

[@costie31]

@@Milamberinx your guess is correct - I have not practiced for a while and it shows😞 Thank you for the correction😁

[@Seth9809]

@@costie31 Watches are worn on the arm.

[@questioner1596]

The same trick works for travel from NL to AK! I never knew that but it's the same 5.5h. I'm guessing there aren't as many direct flights as from NL to AB.

[@davidwilliss5555]

I caught the "as stopped clock is right twice a day comment". By extension, a clock going backwards also reads the correct time twice a day. And the interval between instances of it being right get shorter the faster the clock is going. So logically, a clock going backwards infinitely fast is always right - but very hard to read.

[@MartinPoulter]

A clock going backwards reads the correct time not just twice a day, but four times. The true clock and the backwards clock cross over twice as often as the true clock and broken clock.

[@daggern15]

@@JustOneAsbesto Proverb, not joke.

[@daggern15]

@@JustOneAsbesto As opposed to you

[@KusaneHexaku]

@@JustOneAsbesto congratulations

[@elmomertens]

Small correction! Korea currently does not have half-hour time difference. North Korea was on UTC+8:30 for a while in mid to late 2010s, but they are now back to UTC+9 and South Korea has been consistently on UTC+9 for more than 6 decades now.

[@JoeBleasdaleReal]

I was born in 1997, so am too young to be millennial but too old to be Gen Z. I related to the slot machines in Scarborough but also not being able to read an analogue clock. This episode gave me a huge identity crisis 😂

[@analogicparadox]

97 makes you gen Z by definition. In any case, as a younger person I'm scared of hearing you say you can't read a clock.

[@adamsbja]

That Gen Whatever stuff is heavily regional anyway but gets glossed over. Even just the rich and poor parts of a country/state when you're talking about adopting technology.

[@markusklyver6277]

Born in May 1997 here, never used a slot machine and I do use analog clocks

[@zumabbar]

you're a zillennial

[@Pengu1nRL]

i actually figured this out quite quickly i feel like an absolute genius

[@brandonm8901]

At 0:21 I thought Sabrina got it nice and quick - but the misunderstanding of how a clock works really threw me 😂 Don't know ho no one got it with that really close guess

[@Armadeus]

love how taha brought back the friday horse thing in the newest episode!

[@retroforager]

love that sabrina and i made the same guess and mistake at the same time.

[@zumabbar]

i'm starting to suspect that Melissa had never seen an analogue clock face up until this episode edit: typo

[@apg13997]

06:03 In Tom's defence, performing isn't that far from what he does in all those rallies.

[@akuthia]

This answer should totally be Australian, just so the watches can be "upside down" like the rest of the country :D

[@r0bhumm]

noticed Tom said you had to nudge the hour hand a bit. Think about it if the clock reads exactly 12 o’clock that is both and point to the 12 can you turn it upside down it looks like both has appointed to the sixth and that never happens it’s one of the forbidden positions o’clock hands, in fact, you should be able to tell if a clock is upside down by looking at the weather for the position of the hour hand and the minute hand, even if the numbers were removed.

[@holgerchristiansen4003]

Even as a not Gen Z person, it was interesting to think about a clock face again for the first time in quite a while.

[@bramnet]

To answer Tom's question, the Apple Watch does have accelerometers, but that doesn't rotate the display. What you do instead, is tell the wrist which wrist it is on, and which way and it'll adjust accordingly.

[@jerrymyahzcat]

The Watch will flip upside down but you have to tell it in the settings which wrist you wear it on and which side you have the crown on.

[@cwaldrip]

The Apple Watch does have a feature to change the direction of the face - for left or right handed users.

[@arkarnyay]

So, in the during the clock change or daylight saving time, the upside-down watch can tell UK time and Myanmar time.

[@lakhankabra7722]

As an Indian, I knew the answer after Tom said difference is of 5.5 hours😌

[@undine120]

As a software developer, same.

[@SilverEye91]

Their discussions around what a clock looks like upside down hurts me deeply lol

[@blindleader42]

I think it's adorable that these people say "digital watch" and think "Apple watch" . Ah, youth. According to Douglas Adams, once upon a time, people thought digital watches were a pretty neat idea. Apparently they still do, silly humans.

[@quinnobi42]

The full quote of that is one of my favorite Douglas Adams quotes.

[@mk_rexx]

I think they just put it to the extreme because a digital watch upside down doesn't make much sense in the riddle but a smart watch makes even less sense but it's more comical

[@Squant]

@@mk_rexx When I think of an Apple Watch I picture a digital version of an analogue clock. Isn't that what most people use now?

[@aiocafea]

having used slightly older lcd watches, i can 100% understand what he meant the hour is 88:88 or simply ⬛️⬛️ until you try the right angle, light, mood, spin also there is a video online where he explains himself more about the watch thing

[@giddyaunt9953]

Not sure the question mentioned it was winter - during the summer months India is 4 1/2 hours ahead.

[@ArtSurvivesArtist]

It's hard to make fun of people who make fun of themselves so well.

[@TrondBørgeKrokli]

Interesting to see that Sabrina uses mirrored camera, meaning that her part of the screen shows everything mirrored, hence we see the upside down number XII as correct, although we should have seen the number as IIX (negative 8 if the Romans had known about negative numbers).

[@paulthomas8262]

most webcam conferencing programs do this becuase when you move to the left you don't expect the image of yourself to move to the right, you expect it to follow you like in a mirror. Much of our perception of ourselves is based on our mirror image.

[@globalincident694]

In fact rotating and reflecting like that won't change any number with a horizontal line of symmetry, ie a roman numeral containing no V, L or M

[@AnnaNicole.]

@@paulthomas8262 Maybe Zoom changed since I looked at their settings, but they do have an option to mirror your display... but it only changes what you see of yourself. Others still see you normally. Although I know this has confused some people... I've seen some mirror their virtual background so it would "show up right to others" when they mirrored their own display, yet that really just made it wrong for everyone else.

[@TrondBørgeKrokli]

@@globalincident694 Fair point, although in this case, after having rewatched this video and paused it at the right moments, I found that IX reads as XI (as expected) and III is unchanged (only 12, 3, 6, and 9 is displayed in Roman numerals, the rest is just gradient lines). Why, though, is the V on top reading as a V and not "Ʌ" ?

[@globalincident694]

@@TrondBørgeKrokli When she holds the watch the correct way up (no rotation), it is vertically mirrored, so X, V and I do not change individually, but are reordered. It's only after she applies a rotation that the V becomes Ʌ.

[@Destructificial]

How To Read Clocks with Tom Scott

[@AA_21861]

This also appeared on an episode of QI, where Stephen Fry demonstrated this with his watch.

[@hairyairey]

Got this straight away, but I am obsessive about time zones. It was deliberate, then we went and ruined by adding daylight savings time

[@quinnobi42]

I'm not older than the answer in progress crew and I can read an analogue watch, which made it kind of surprising that they took so long to figure it out.

[@PianoKwanMan]

I've spent too many seconds in hotel foyers where they have clicks of international locations to know this answer straight away. I think it's amounts to minutes over 30 years

[@ragreen2]

I often will turn my watch upsidedown (or put it on the other wrist) in lieu of tying a string on my finger to remind me of something.

[@rebelmage6929]

I always wear a watch, so I could look at my own watch for this, which made me figure out the half hour thing. I didn't know what countries have it, but I did remember there are countries with a UTC-offset that isn't just a whole hour... (Also, looking at your own watch upside down is uncomfortable.)

[@shaunhouse8469]

It kind of changes the time by 5 and a half hours I think, which would mean she'd be from India. The hour hand is off by half a sector. It could be read as 6.5 hours to because of little hand being half an hour off but no-one works on British time + 6.5

[@guessundheit6494]

When it said "upside down" I was expecting it to involve the pin and wearing the watch on the left arm. There are left handed watches with the time adjusting pin on the LEFT side, so that the watch can be worn on the RIGHT arm. For ignorant right handers who can't figure out why, it's so that the watch doesn't catch on the table or other things as a left handed person uses a pen or a pencil.

[@whynotanyting]

I kept thinking it was a novelty 24 hour analog clock

[@hmoham]

My parents returned from their holidays in India just last week, so soon as the five and half hour was mentioned I guessed India.

[@happyowl08]

Won’t the watch show either a 5.5 or 6.5 hour difference depending on whether in the first or second half of the hour?

[@timothymclean]

No? Why would the time jump forward or backwards by an hour when the minute hand crosses the twelve?

[@happyowl08]

@@timothymclean Try drawing 1:15, 1:30, and 1:45 on a clock face and turn the drawings upside down. I see 7:45, 7:00, and 7:15, respectively. The issue is that the rotation makes the minute hand always 30 minutes off, but the hour hand *doesn’t* change. In the first half of the hour, being 30 minutes off means going forward within the hour, and in the second half it means going backward.

[@CallieMasters5000]

I heard this decades ago. I thought this was fairly well known.

[@jannepeltonen2036]

But how can young people *not* be familiar with analog clocks? Aren't there public clocks on railway stations, church towers, municipal houses etc? Wouldn't you be seeing those every day, even if you yourself didn't have one?

[@DuncanJimmy]

The immediate thought I has was of nurses who used to wear an analogue watch upside down hanging from a ribbon at the top of their blouse/ apron. This had two obvious benefits: - the more buxom the lady, the easier it was for her to read the watch; - he/ she never had to worry about a wristwatch carrying germs from one patient to the next because of how difficult they are to clean on top of doing hands every 5 minutes.

[@Slikx666]

🤔 never knew that.

[@JohnDoe-tx8lq]

To change an analogue watch you just spin a tiny dial on the side... it's QUICKER than taking the thing off, putting it back on and then constantly trying to look at the weird numbers to tell the time... naaa, no point!! 🙂

[@justandy333]

Afghanistan also has the time difference in half hour increments. But it wouldn't have worked in this situation as its 4 1/2 hours difference from GMT. The only reason I know this is because a friend of mine served in the RAF at Kandahar Airfield.

[@nmanbamboo1980]

My dad told me this thing is school in 2nd grade, turn the clock face upside down and you get London time.

[@purplelord8531]

6:00 performing is accurate, lmao

[@jerrygaguru]

Also Ethiopia

[@Pencilneckgeek216]

Afghanistan also has a half hour time difference and borders Pakistan, so I was a little surprised to hear that it was India, although that it definitely a more "major" country than Afghanistan.

[@Pencilneckgeek216]

Also, it's definitely a 6.5 hour difference if you flip the clock upside down.

[@seraphina985]

@@Pencilneckgeek216 To be fair a time difference of -0530 or +0630 would both work with a 12 hour clock you are correct on that. This of course being because they display the same output regardless whether it is AM or PM. Thus starting at 12 pm for example you can flip it upside down and read it as either 6:30 am (-05:30) or 6:30pm (+06:30). Of course there is nowhere with a time difference of +06:30 from London Heathrow thus why with the story as presented there is only one valid solution that makes it work simply due to the fact the other possible time zone is not in use. Actually come to think of it that doesn't actually work for India as it is +05:30 so seems like someone buggered up the story somewhere actually.

[@lateralcast]

The question says "visiting". Her watch was originally 12.30pm in the UK, where she lives. When she flies abroad, rather than reset her watch, she turns it upside down to get 6pm, local India time. (As Tom mentions, you have to nudge the hour hand slightly in your head.) She is found back in the arrivals lounge before she's had a chance to turn the watch back around.

[@teh-maxh]

They do make watches that have a 24-hour dial.

[@fltchr4449]

Jokes on me! My watch has a 24 hour dial! Looking at it now, 19:30 becomes 8:00, if I take the hour hand to be ahead. So that's a 12 1/2 or 11 1/2 hour difference, if I did the math right. So, a 24 hour dial is flippable for the difference between mountain time in the United States and India?

[@sandwich2473]

This is a towards the end guess but Isn't Afghanistan a country with a .5 hour timezone?

[@sandwich2473]

Aoouuggghhhhh not quite

[@meganesia1]

Please post the footage of Sabrina’s cat!

[@lateralcast]

twitter.com/lateralcast/status/1632702365382877185

[@meganesia1]

@@lateralcast yayyyyy!

[@WyvernYT]

Thank you! That's adorable. Also, the cat does not look impressed with us.

[@m4rcyonstation93]

wrong description

[@m4rcyonstation93]

they fixed it

[@GryphLane]

Smug mode because I knew what the answer was going to be before hearing the question

[@GryphLane]

(She was from southern Asia, -5.5 from GMT)

[@donkfail1]

She had been in The Upside Down?

[@marpintado]

It´s a lazy person trick, when someone asks you the time you just show the watch and the watch face will be upright to the person🙃

[@terrydactil]

Not quite true! Normal clock has the hour hand aligned with the hour marking when the minute hand is vertical up (->0/12) Upside down clock with minute hand vertically up (->6/30) will have the hour hand halfway between the hour digits. You will need to read the minutes with zero at the bottom, or just ignore the minute hand completely.

[@ToppyTree]

4:53 "you have to nudge the hour hand a bit in your head"

[@AngryKittens]

My guess (haven't finished the video): she was from Fiji EDIT: India? I still don't understand. EDIT2: Oh. It only works if you imagine the position of the numbers remain the same. So only the hour and minute hands get reversed.

[@jordansean18]

This whole episode seemed unfairly difficult for gen Z 😅

[@jordansean18]

@@EightThreeEight well, I can't, because I'm merely a millennial making observations 😅

[@I_Love_Learning]

@@EightThreeEight I am a substitute teacher, and from my inference, about half of current day students know how to tell the time, and it doesn't really seem to correspond to having digital watches and such. I think it was a skill that people learned but was really skipped over and you could only really learned if you cared.

[@jannepeltonen2036]

So I had xclock running on another virtual desktop, changed there, and turned my laptop upside down, and realized immediately what happens to the minute hand :D

[@arimago]

a few of the more significant assumptions made by this riddle, each one of which i think is enough to make it an invalid or "bad" riddle: - the minute hand, not hour hand, is exactly correct on the resulting watch face. this creates an ambiguity wherein: - the hour hand misaligned by 15° is assumed to be running ahead (as in India), not behind (as in Myanmar) - someone at Heathrow Airport is native to London, or to the GMT time zone generally (Heathrow is in this time zone for about 43% of the year; about one-third of travellers at Heathrow are connecting) - the analogue watch in question reads 12-hour time, rather than 24-hour or any alternative time representation methods - the watch is set correctly and the wearer is knowledgeable about its correct orientation (it's not for fashion or as a covert signal) - the wearer somehow prefers turning the watch upside-down to simply setting it correctly for the new time zone. most watches allow you to set the time by turning the side crown - the wearer suffers from a severe skill issue in which basic maths cannot be used to tell time in two time zones at once

[@lateralcast]

There might be 10 other reasons why she wears the watch that way, but this trick is used by many people and is a likely solution. If we have to list all the possibilities, the show never ends.

[@gorgonzola86]

How would they have known she was not from Nepal instead?

[@Phoenix_Vizvai]

6 ½ is 5 ½ on a clock 😂

[@oooSIDEooo]

So, was she Indian and visiting the UK, or British and visiting India?

[@metfan999]

I dont understand how flippping your watch would do any good.

[@JudithOpdebeeck]

I keep thinking this is a bit pointless. Like they still don’t know who she is or anything. They literally only know where she went

[@abel6846]

India!

[@ankitsonariya918]

Performing is usually the right word for Narendra Modi, Tom😂

[@Gracefitzknits]

I used to wear my watch upside-down because I was qUiRkY and rAnDoM

[@cykkm]

Fk, I computed UTC+06:30 and Myanmar even before Tom ended reading the question. Turning clock at angles is not an easy feat. I'm a PhD. You mean, _the security guard immediately calculated it correctly?_ Either 💯 believable, or I lived my life for nothing-I should have become a security guard, not an insecure grad...

[@mnchls]

...but why did she not have any identification?

[@UserUnknown07]

Someone stole her purse

[@Z_MIB]

There's no way to tell what country she came from since anyone can put their watch on upside down.

[@randomperson-oi9vj]

today i learned that the brits spell the word "analog" differently than in the us

[@zumabbar]

taha is pakistan??

[@christam949]

the zoomers just killing the olds with not knowing what an analog clock face looks like or the very common nickname for slot machine haha also, addendum, i think andy zaltsman on the bugle or one of his guests had mentioned this fact too having travelled to india.

[@UserUnknown07]

Narendra Modi 🔥

[@glkglkglkglk9193]

You really think he came up with it..

[@UserUnknown07]

@@glkglkglkglk9193 Well, he shared it.