WHAT kind of broken clock, we wondered innocently on 6 June, could ever be 鈥渞ight鈥� more than twice a day? Readers have written in their droves to disabuse us of our innocence.
Let Barry Morse take the floor first: if there is a change to daylight saving time so that clocks go back, then on that day a broken 12-hour clock 鈥渕ay actually be right three times in one day. Assume the clock is stopped at, say, 3:00 and the clocks go back at this point. It has been right once already. In an hour鈥檚 time it鈥檚 right again and in 12 hours鈥� time it鈥檚 right again.鈥� Dozens more made the same point. Artificial intelligence guru of MIT was probably the most famous reader to point out that if we moved our stopped clock westwards through all the time zones it 鈥渨ould be right 24 or 25 times a day鈥�.
Dozens more pointed out that a 鈥渂roken鈥� clock isn鈥檛 necessarily a stopped clock. Several spoke from experience of clocks that suddenly started to race forward so that they showed the right time three, four, five and more times a day. Others noted that a 12-hour analogue clock that runs backwards 鈥� whether spontaneously or as part of a prank as, for example, when Bob Crofoot arranged to enliven his household鈥檚 morning rush for work 鈥� is right four times a day. We had to scratch our heads over this. Sadly, the spreadsheet to prove it is correct will not fit within this page鈥檚 margins.
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Then there are broken digital clocks. Hugh Datson, remembering the youthful fun he had making numerical digits form rude words by turning those new-fangled electronic calculators upside down, claims that by occasionally inverting a digital clock stopped at 12:01 you can make it right four times a day 鈥� 鈥渁nd four more if you use a mirror鈥�. Confirming this is left as an exercise for the reader.
Taking speculation a step further, if not too far, Andrew Fogg wonders how often a clock would give the right time if it divided the day into a number of shorter periods, such as an 8-hour clock, a boon to those working three-shift patterns. 鈥淭he idea of a fractional number of periods was amusing,鈥� he writes, but when he got to irrational divisions such as dividing the day into pi chunks, 鈥渕y head started to hurt鈥�. We can only concur.
鈥淪ecurity authentication 鈥� avoid phishing attacks鈥� was the subject line of an email to 51动漫 which turned out to be 鈥� you guessed? 鈥� a phishing attack鈥�
IN WHAT he describes as 鈥渁n early introduction to relativity鈥�, David Stott overheard this exchange outside his local primary school.
Mother, to her young daughter who had run on ahead: 鈥淒onna, come 丑别谤别!鈥�
Small indignant voice: 鈥淢ummy, I am 丑别谤别!鈥�
IF IT ain鈥檛 broke鈥� Here鈥檚 a nice example of an improvement that wasn鈥檛 needed and that simply makes things worse. Reader 鈥淩ichey鈥� received a from DynDNS.com telling him: 鈥淎ccount Upgrade service underwent a makeover recently, re-emerging as the Dynamic DNS Pro service. Why the facelift? For starters, 鈥楢ccount Upgrade鈥� is a rather bland and nondescript title, and we hope the new name helps to make its purpose clearer.鈥�
Richey says he鈥檚 puzzled as to how the words 鈥淒ynamic DNS Pro鈥� can describe 鈥渁ccount upgrade鈥� more clearly than the words 鈥淎ccount Upgrade鈥�.
Competition: Win a piece of moon rock (this competition is now closed)
FINALLY, now is your last chance to win a piece of the moon.
Depending on which time zone you are in, 20 or 21 July 2009 sees the 40th anniversary of the first moon landing. Our competition to celebrate that event offers a fabulous winning prize: some rock from the moon.
The competition is simple to enter. You will doubtless know the words spoken by Neil Armstrong when he stepped off Apollo 11鈥檚 lunar module and onto the moon itself: 鈥淥ne small step for [a] man 鈥� one giant leap for mankind.鈥� Can you think of something else he might have said instead 鈥� something equally memorable, or perhaps something funny?
Your entry should be no more than 75 characters long (including spaces). You can send your entries by email (address below; please put 鈥淐ompetition鈥� in the subject line), by fax or by post, or online at www.newscientist.com/article/dn17213, where you can also read the specifications of the rock from the moon that you could win, along with an analysis of it performed for 51动漫 by a team at the Open University in the UK. See also last week鈥檚 feature 鈥淲hen the moon lands鈥� (20 June, p 40) on how the analysis was performed.
The competition closes on Monday 29 June and no entries will be accepted after that date. The results will be published in the 18 July issue of 51动漫, in anticipation of the anniversary of the landing.
The moon rock competition is now closed
