From: Damien Broderick (d.broderick@english.unimelb.edu.au)
Date: Tue May 29 2001 - 21:01:14 MDT
http://www.telegraph.co.uk:80/et?ac=000947301843789&rtmo=ax8asxHL&atmo=rrrrr
rYs&pg=/et/01/5/27/nmurp127.html
Breakfast at Murphy's (or why the
toast lands butter-side down)
Robert Matthews,
Science Correspondent
NO longer ridiculed as a myth, scientists have proved that Murphy's Law is
true: if toast can land butter-side down, it will do.
Today, The Telegraph exclusively reveals the outcome of the world's
biggest-ever investigation into Murphy's Law, which states that, if things
can go wrong, they will go wrong. In a mass experiment carried out in
schools across the country, schoolchildren put toast on to plates, and
watched what happened when the slices slid off. And they proved beyond
reasonable doubt that Murphy's Law is at work at the breakfast table.
Of almost 10,000 trials, toast landed butter-side down 62 per cent of the
time - far more often than the 50 per cent predicted by sceptical
scientists. Based on so broad a study, the probability of achieving so big
a difference by chance alone is vanishingly small. So, for optimists
everywhere, there is no escaping the bleak reality of Murphy's Law.
For me, as a confirmed pessimist and scientific consultant to the project,
the outcome of the mass experiment marks the end of a seven-year quest to
confirm my darkest suspicions: that things go wrong because the universe is
made that way.
My quest began in June 1994, after I read a letter in New Scientist
magazine. Colin Morgan, from Warrington, claimed to have found the reason
why toast so often lands butter-side down: as it falls off a plate, it
doesn't have time to complete a full spin, bringing the buttered side back
up again before hitting the floor. Anyone doubting his explanation should
perform an experiment, said Mr Morgan: "Push a piece of bread slowly over
the edge of a table. See?"
Along with, I suspect, many other people, I initially thought that Mr
Morgan had simply not performed his experiment often enough. Had he done
so, he would surely have confirmed what every scientist knew: that toast is
just as likely to land butter-side up as down.
Indeed, a team of scientists had proved precisely this in an experiment
carried out in 1991. After getting people to toss buttered bread in the air
300 times, the results were statistically indistinguishable from the 50:50
split of a coin-toss. It seemed obvious that Murphy's Law of toast was
really nothing more than selective memory, with people remembering only the
50 per cent of times when the toast lands butter-down.
After repeating Mr Morgan's experiment with a paperback book, however, I
realised that he was on to something. The book unquestionably had a
tendency to land face-down, slowly spinning as it fell to land. This
clearly had implications for toast, which usually ends up on the floor
after sliding off plates - not after being tossed into the air. It dawned
on me that the "scientific" experiments had not disproved Murphy's Law at
all: the scientists had simply performed the wrong experiment.
Detailed calculations of the dynamics of tumbling toast confirmed my
suspicions, and revealed something else: that the presence of butter was
more or less irrelevant. Neither its weight nor aerodynamic properties had
much effect on how toast landed. The crucial factor is purely height - and
toast sliding off a plate spins so slowly that only if it falls from
heights above 8ft does it have much hope of regularly landing butter-up.
Publication of my calculations in the European Journal of Physics in 1995
sparked an enormous response: television crews from countries from
Australia to Brazil turned up, demanding to see toast fall butter-down on
my kitchen floor. Yet, all the while, I was nagged by the fact that my work
was, in the end, "theoretical". I still wasn't sure whether real toast
obeyed my back-of-the-envelope estimates.
After that, and putting my doubts about toast to one side, I moved on to
investigate other notorious manifestations of Murphy's Law, such as why the
queue you're in is so often beaten by the one next to you, and if the place
you're looking for in the road atlas can lie on an awkward part of the map,
it will. Time and again, these myths turned out to have a solid basis in
fact. My research won awards, and I was invited to give a discourse on my
findings to the Royal Institution. Yet still my worries over tumbling toast
remained.
The chance to resolve them finally came a year ago. Lurpak, the butter
manufacturer, was setting up an educational project for schools, and
wondered if I could devise an experiment based around Murphy's Law of
toast. Together with staff from the Maths Year 2000 programme of the
Department for Education, we drew up plans for the biggest-ever
investigation of Murphy's Law, involving schoolchildren from across Britain.
Here was a golden opportunity to put my calculations to the ultimate test:
a nationwide study that would produce thousands of data-points. The
experiment consisted of three tests. The first was aimed simply at finding
out whether toast really did land butter-side down more often than not. To
perform the experiment, each pupil was asked to put a piece of toast on a
plate, let it slide off 20 times and note which way up it landed.
The second experiment probed Murphy's Law of Toast a little deeper. This
time, the toast had nothing on it apart from a letter "B" written on one
side in marker pen. My calculations suggested that butter played little
role in deciding the fate of toast. If they were right, then even toast
marked only with a "B" should still land more often "B"-side down.
The third experiment studied the effect of height on tumbling toast.
Secondary school students were asked to let toast tumble from heights above
8ft. If the theory was correct, this would lead to toast landing
butter-side up significantly more often than down.
The Lurpak Tumbling Toast Test began in March and ended earlier this month;
more than 1,000 children took part, with toast tumbling off plates more
than 21,000 times - making it by far and away the biggest-ever study of
Murphy's Law.
The results, I'm relieved to say, were in complete agreement with the
theory. The first experiment, with its 62 per cent face-down rate, clearly
confirmed Murphy's Law. In the second test, designed to probe the effect of
butter, the toast still landed 58 per cent of the time on the side marked
"B" - a rate just four per cent lower than that with butter. This confirmed
that, despite what many believe, butter is not the prime cause of the trouble.
The real culprit was revealed by the outcome of the final experiment. Of
more than 2,000 tumbles from heights above 8ft, the toast landed face-down
only 47 per cent of the time - confirming that it is only from such a great
height that toast has much chance of landing butter-side up.
The children reported their results via the Maths Year 2000 website and it
was clear that they relished the chance to use science to test their own
theories about what was happening. Many came up with suggestions for
beating Murphy's Law - along with evidence to back their claims. My
favourite was from Hannah, seven, at the Good Shepherd Primary School in
west London: "Butter the other side."
Thanks to their efforts, the cause of a familiar source of frustration has
finally been identified. Toast lands butter-side down because we humans
aren't tall enough to let it land any other way. I am left with only one
small worry. If Murphy's Law really is true, how come all the experiments
went so well?
----------
4 March 2001: Pupils to judge Murphy's Law with toast test
<http://www.telegraph.co.uk:80/et?ac=000947301843789&rtmo=ax8asxHL&atmo=rrrr
rrYs&pg=/et/01/3/4/nmurph04.html>
5 April 1997: [Features] Murphy really does sock it to us
<http://www.telegraph.co.uk:80/et?ac=000947301843789&rtmo=ax8asxHL&atmo=rrrr
rrYs&pg=/et/97/4/5/eslaw05.html>
8 September 1996: It's just bad luck that the 13th is so often a Friday
<http://www.telegraph.co.uk:80/et?ac=000947301843789&rtmo=ax8asxHL&atmo=rrrr
rrYs&pg=/et/96/9/8/nthirt08.html>
15 April 1996: Long arm of Murphy's Law can turn life into a trial
<http://www.telegraph.co.uk:80/et?ac=000947301843789&rtmo=ax8asxHL&atmo=rrrr
rrYs&pg=/et/96/4/15/nsod14.html>
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