A clock for math whizzes

Update 7:40 p.m. PST January 6: Thanks to alert reader OneGB for supplying the origin of the clock. The central design may look like a bungled biohazard symbol, but it in fact is another three-nine reference, the "hurricane" symbol of a high-IQ organization called the Triple Nine Society. The group also sells Triple Nine aprons, mugs, bibs, underwear, and other whatnot at CafePress.com.

(Credit: Dean Hunt, StreetLessons)

Math enthusiasts who don't want to move totally into the digital realm might appreciate this analog clock.

Each number is expressed as a calculation involving three instances of the number 9.

For example, 5 o'clock is the square root of nine (3), factorial (3x2x1 = 6), minus 9/9 (6-1 = 5).

The trickiest time is 7 o'clock, whose calculation works out to 6.99999..., with an infinite number of nines. Wikipedia assures us that 0.99999... really does equal 1, so no worries that the clock is cheating there.

While we're on the subject of archaic clock technology, how come clocks and watches with Roman numerals represent 4 o'clock with IIII rather than the traditional IV? A friend told me it was because it was easier for illiterate people to comprehend, but I'd love to see some history about this.

(Via Bad Astronomy Blog.)

[kallemia]

IIII vs IV

Lots of supposed reasons.... take your pick at: http://www.ubr.com/clocks/frequently-asked-questions-faq/faq-
roman-iiii-vs-iv-on-clock-dials.aspx

[MCOjerry]

This seems like a plausible explanation...

http://www.bhi.co.uk/hints/roman.htm

[Fe1d]

The two most compelling reasons: (1) Roman numerals were based on tally sticks without subtractive notation, which later became optional, and only became standard in modern times. (2) By using IIII, clock makers could cast one mold of VIIIIIX four times, then separate them as V IIII IX, VI II IIX, VII III X, and VIII I IX to make all the numbers.
http://en.wikipedia.org/wiki/Roman_numerals#IIII_vs._IV

[Hogleg MacDrillun]

IIII vs IV

My brother (the horologist) tells me that it is assumed that "IIII" balances out the "VIII" from the 8 opposite the 4 when painting watch dials. He has added that historically, no one is sure why they use "IIII", and he has heard about every excuse. I asked him once about the illiteracy story and he basically didn't buy it, arguing that the kind of people likely to own a watch were most likely capable of simple arithmetic.

[Shankland]

True, but there were also public clocks

I'm sure there was a correlation with wealth, education, and the availability of clocks, but there were a fair number of publicly visible clocks in urban areas, notably churches I'd think. Anyway, just a thought.

[megapenitent]

why not...

why not (√9) + (9/9) for 7?

PS: sorry if someone already posted that one, my mac is suffering
from crippling lag.

[megapenitent]

square root character is not recognized, apparently...

and i also left out the factorial, so it would be ([SQUARE ROOT]9)! +
(9/9)

[Rarb3]

Re: Why not Fact(SqrRt(9)) + (9/9) ...

Because it wouldn't be very imaginative, given that the solution for 5 was almost the same:
Fact(SqrRt(9)) - (9/9)

[OneGB]

Since a source for the clock wasn't given...

Check out the Triple Nines:
http://www.triplenine.org

Or you can get the clock at their cafepress site:
http://www.cafepress.com/triplenine#housewares

[p_manohar]

Why not...

Well, I would say why not use the following -
(9/sqrt9)+(9/sqrt9)+(9/9)?

[markdoiron]

Too Many Nines

The clock uses only three instances of nine at each hour digit. --mark d.

[atanasentchev]

Stretching It

A kind of funny concept that doesn't quite click...

Like you need to actually perform the calculations to find out what time it is. Some of the most popular watch interfaces do not include any numbers on the face (Rolex). Others (Movado), do not include ANY MARKERS, except for a shiny thingy at 12.

[otterskibum]

but very cool nonetheless.....

That's what makes it so unique and very cool. Very different from
any other clock....

[andyengle]

Hmm... what time is my date again?!

Oh wait, with this clock I probably won't be getting any dates, so it
doesn't matter.

[mbelisle]

Also 7.000...01 = 7

But 0.99999... really is equal to 1, so the result is exactly 7 and just
as accurate. Summarizing a proof in the Wikipedia article, 1/9 =
0.11111.... Hence, 9/9 = 9*1/9 = 0.99999... = 1.

[mbelisle]

See megapenitent comment above for context

This was supposed to be a response to "Why didn't CNET code
the..." by megapenitent above. The "Reply to Story" and "Reply to
this Comment" buttons are like right next to each other.

[volterwd]

7.0000....01 is not a number

unless its a finite length.

In other words there is no number immediately after 7. Or immediately after any other number for that matter.

[godseyesore]

7

6.999.....to infinity does not equal 7.
Clock is broken from get-go!

[volterwd]

If this was tongue in cheek...

where was your tongue... 6.999... is 7.