1. The curse of Friday 13th?
A paper published in the British Medical Journal in 1993 examined whether Friday the 13th is bad for your health. The researchers found that, despite there being fewer vehicles on the road on Friday the 13th, there were more injuries from transport accidents.
However, whilst emergency admissions due to accident or poisoning were found to be higher on Friday the 13th than on Friday the 6th, the differences were not statistically significant.
2. Fingers crossed!
Crossing your fingers is a popular and enduring superstition to bring good luck or show support in many western countries. Pagans believed that the cross (made by two people crossing index fingers or their own index and middle fingers) was a powerful symbol and that at the intersection there was a concentration of good spirits.
They could therefore wish on the mid-point of the cross to fulfil their wishes and fight off evil spirits. But beware: in Vietnam, crossing your fingers is seen as an obscene gesture!
To try and ward off bad karma, if given the race number 13, riders will often wear it upside down.
3. Race number ‘13’
Professional cyclists are a superstitious bunch, perhaps with good reason, as so many aspects of bike racing are out of a rider’s control.
The tragic events on Friday the 13th July 1967 during the 13th stage of the Tour de France when Tommy Simpson died on the ascent of Mont Ventoux have done little to reduce superstitions in the peloton. To try and ward off bad karma, if given the race number 13, riders will often wear it upside down.
4. Unlucky for some
In many countries, the number 13 is commonly associated with bad luck, but it isn’t the only ‘unlucky’ number. In China, the pronunciation of ‘4’ is similar to that of ‘death’ or ‘decease’. Many buildings do not have any floors starting with 4, and patients avoid having surgery on a date containing a 4.
VIXI (an anagram of ‘17’ in Roman numerals) is Latin for ‘I have lived’ and is commonly found on headstones in Italy. Consequently, the number 17 is unlucky and is associated with tempting death. Alitalia misses out row 17 on its aircraft.
5. Omen-ous thunderstorms
Ancient cultures believed that thunder and lightning were messages from the gods. The Romans feared thunder and believed that hearing it on your right side was bad luck. Depending on which day of the week thunder was heard, it could signify anything from the death of a beggar to widespread death.
In the Middle Ages it was thought that thunder signified demons in the sky and dark-arts practitioners specifically performed ceremonies during thunderstorms, believing that evil spirits were close to the Earth. However, the Victorians believed that thunder at a funeral signified a soul being accepted into Heaven.
6. Always check your units
July 23rd 1983. An Air Canada Boeing 767 crash landed at an air force base/motor-racing track in Gimli, Manitoba, having glided down from 12,000 metres after running out of fuel.
The main cause was that ground staff and the pilot used the wrong units when re-fuelling.
The main cause was that ground staff and the pilot used the wrong units when re-fuelling, calculating the fuel on board in pounds rather than kilogrammes and hence taking on 4,900 litres rather than the 20,000 they needed.
They were unlucky for four reasons: Canada was new to the metric system and flight paperwork still featured imperial conversion factors; the 767 was only four months old and checklists were still in flux; fuel gauges were faulty; the 767 was the first plane to have a pilot and co-pilot, but no flight engineer, who normally checked the fuel. However, the captain was an experienced glider pilot, and all 61 passengers (plus motor racers) walked away uninjured!
7. Fluttering in the breeze
The Tacoma Narrows Bridge collapse is particularly famous amongst engineers. The suspension bridge in Washington state opened in 1940 and collapsed spectacularly in the same year. Moderate winds (under 40mph/64km/hr) generated huge twisting oscillations in the bridge deck that ultimately tore it to pieces.
The cause was a phenomenon called “aeroelastic flutter”, in which aerodynamic forces generate and feed a resonant vibration in the structure.
8. Killed by Code
The Therac-25 was a computer-controlled radiation therapy machine that was withdrawn from the market in 1987 following an intensive investigation into over-dosage treatments, which led to the death of four patients and life-changing injuries to two others.
Two software bugs were found to be the cause of the malfunctions, but perhaps more fundamentally, the hardware interlocks present in earlier systems had been replaced with computer control.
The poor system design, minimal risk and fault analyses, and inadequate testing of the Therac-25 has had a significant influence on the design and development processes of medical devices today.