Blink free photos win IgNobel
Research that calculates the number of photos you need to take to make sure no one in the group has their eyes closed has won two Australians an Ig Nobel award.

Nic Svenson and Dr Piers Barnes of CSIRO Industrial Physics have been awarded the Ig Nobel Prize for mathematics at a ceremony at Harvard University.

"I end up doing a lot of group photographs and the number of people blinking in photographs is driving me nuts," says Svenson, a CSIRO communications officer.

So she thought there had to be some kind of rule to figure out how many photographs to take to make sure she got a good one.

Svenson researched basic information on how long a blink lasts, how many times people blink per minute and how fast camera shutters go.

Barnes, a physicist, worked out that blinks are random and that one person's blinks don't influence another person's blinks. And unless you have got something stuck in your eye, your blinks don't influence each other either.

"He came up with a graph showing the probability of having someone blink in a photograph," says Svenson.

"Then he was able to do the reverse of that equation, as it were, to come up with the number of photographs to take."

The two found out that when you're taking photos of a group with fewer than 20 people you divide the number of people by three to get the number of shots you need to take.

But in bad light the camera shutter is open for longer and this gives people more of a chance to blink while a photo is taken. So in bad light you need to divide the number of people by two to get the number of shots.

As the size of the group increases, the number of shots you need to take increases exponentially, says Svenson.

And by the time there are around 50 people in the group, she says you can "kiss your hopes of an unspoilt photo goodbye".

Fingernails scraping on a blackboard
The winner for the Ig Nobel prize for acoustics went to three scientists who investigated responses to the sound of fingernails scraping on a blackboard.

The study, called 'Psychoacoustics of a chilling sound', found that scraping fingernails was the most annoying sound out of 16 sounds tested.

It was much more annoying, for example, than the sound of a dragged stool, a metal drawer being opened, scraping wood, scraping metal or rubbing together two pieces of polystyrene foam.

The research, which was published in the journal Perception and Psychoacoustics in the 1980s, concludes that "acoustic energy in the middle range of frequencies audible to humans" is the culprit.

But it could not answer why such sounds were so grating to the ear.

Teen repellents and headache-free woodpeckers

Still on acoustics, the Ig Nobel peace prize went to the developers of a device that makes an annoying noise that teenagers can hear but not adults.

The device, which emits a super-high-pitched mosquito-like buzz, was originally used as an electromechanical teenager repellent and later used for telephone ringtones that teenagers could hear but not their teachers.

Still on mosquitoes, the Ig Nobel prize for biology went to researchers who reported in The Lancet that the female malaria mosquito, Anopheles gambiae, is attracted to the smell of Limburger cheese just as much as to the smell of human feet.

The Ig Nobel prize for medicine went to the authors of case reports in medical journals on the 'Termination of intractable hiccups with digital rectal massage'.

The winner of the Ig Nobel prize for ornithology was a professor of ophthalmology who helped explain why woodpeckers don't get headaches.

The Ig Nobel prizes honour achievements that first make people laugh and then make them think.

They are produced by the science humour magazine, The Annals of Improbable Research.

Author Anna Salleh
Publication ABC Science Online
Date 06 October 2006
Link www.abc.net.au