Serendipity A bit of a snag

IN 1948, George de Mestral went for a quiet walk in the Swiss countryside. Just like millions of people before him, he returned home to find his trousers covered in burrs, but, unlike everybody before him, Mestral wanted to find out about the mechanism behind these pesky and persistent seed cases. He put one of the burrs under his microscope, and saw that its surface was covered in tiny hooks; these had been responsible for latching on to the loops of fibre in his trousers.

Mestral decided to replicate the hook and loop mechanism in order to produce a fastener for everyday use. Working with the recently developed nylon, he was able to mass-produce sturdy loops, but he was stymied when it came to making the accompanying hooks.

Eventually, he realised that he could create hooks simply by cutting the loops, and thus Velcro was born. The word is a combination of velvet and crochet (the French word for hook), and although it is commonly used to describe all hook and loop fasteners, it is actually a registered trademark, like Hoover and Sellotape.

Velcro is now ubiquitous. Astronauts use it to keep tools from floating away, and a stainless steel version of Velcro is used for attaching insulation in nuclear power plants, where the temperature is 500C. There is even a special silent Velcro used by the military.

Velcro is so strong that a patch as big as a CD can support the weight of a person, and yet the patch can be easily peeled away between two fingers. This mixture of strong bonding and easy peeling is a result of so-called dimensional reduction. If you try to pull apart a patch of hooks and a patch of loops, then the force is spread over the entire area and is ineffective. But if you try to peel the two patches apart, then the force is focused along a single line. In short, applying a force in two dimensions fails to separate the patches, but concentrating it along one dimension works.

The zip functions in exactly the same way, except it deals in one less dimension. If you grip two pieces of zippered fabric and try to pull them apart, the force is spread along the entire length (one dimension) of the zip, and the two pieces of fabric should hold fast. In contrast, the zipper mechanism that actually unravels the zip focuses all the force at a single point (zero dimensions).

Following Mestral's study of burrs, biologists have recently discovered other natural examples of Velcro. The predatory decorator crab uses hooks on its shell and legs to accumulate sponges and other marine life, thus camouflaging the crab. Conversely, sponges belonging to the family Cladorhizidae feed by using their in-built loops to snag crustaceans. Cells from the sponge then smother and digest the crustacean. .

Suggested Topics
Arts and Entertainment
Eddie Redmayne with his Screen Actors Guild award for Best Actor

film
Arts and Entertainment
Rowan Atkinson is bringing out Mr Bean for Comic Relief

TV
Arts and Entertainment

Theatre

Arts and Entertainment
V&A museum in London

Art Piece taken off website amid 'severe security alert'

Arts and Entertainment
Over their 20 years, the band has built a community of dedicated followers the world over
music
PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Arts and Entertainment

ebooksNow available in paperback
Arts and Entertainment

ebooks
Arts and Entertainment
Reese Witherspoon starring in 'Wild'

It's hard not to warm to Reese Witherspoon's heroismfilm
Arts and Entertainment
Word up: Robbie Coltrane as dictionary guru Doctor Johnson in the classic sitcom Blackadder the Third
books

Arts and Entertainment
The Oscar nominations are due to be announced today

Oscars 2015
Arts and Entertainment
Hacked off: Maisie Williams in ‘Cyberbully’

Maisie Williams single-handedly rises to the challenge

TV
Arts and Entertainment
Eddie Redmayne in The Theory of Everything and Benedict Cumberbatch in The Imitation Game are both nominated at the Bafta Film Awards
Arts and Entertainment

Academy criticised after no non-white actors nominated

Arts and Entertainment
Damian Lewis shooting a scene as Henry VIII in Wolf Hall
TV

Arts and Entertainment
A history of violence: ‘Angry, White and Proud’ looked at the rise of far-right groups

tv

An expose of hooliganism masquerading as an ideological battle

Arts and Entertainment

art

Lee Hadwin can't draw when he's awake, but by night he's an artist

Arts and Entertainment

TV

Arts and Entertainment
Michael Keaton in the 1998 Beetlejuice original

film

Arts and Entertainment

TV

Arts and Entertainment
Olivia Colman and David Tennant star in 'Broadchurch'

TV

Arts and Entertainment
Michael Kitchen plays Christopher Foyle in ITV's 'Foyle's War'

TV
Arts and Entertainment

TV
Arts and Entertainment
Downton Abbey star Joanne Froggatt will be starring in Dominic Savage's new BBC drama The Secrets

Arts and Entertainment
Vividly drawn: Timothy Spall in Mike Leigh’s ‘Mr Turner’
film
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    Syria crisis: Celebrities call on David Cameron to take more refugees as one young mother tells of torture by Assad regime

    Celebrities call on David Cameron to take more Syrian refugees

    One young mother tells of torture by Assad regime
    The enemy within: People who hear voices in their heads are being encouraged to talk back – with promising results

    The enemy within

    People who hear voices in their heads are being encouraged to talk back
    'In Auschwitz you got used to anything'

    'In Auschwitz you got used to anything'

    Survivors of the Nazi concentration camp remember its horror, 70 years on
    Autumn/winter menswear 2015: The uniforms that make up modern life come to the fore

    Autumn/winter menswear 2015

    The uniforms that make up modern life come to the fore
    'I'm gay, and plan to fight military homophobia'

    'I'm gay, and plan to fight military homophobia'

    Army general planning to come out
    Iraq invasion 2003: The bloody warnings six wise men gave to Tony Blair as he prepared to launch poorly planned campaign

    What the six wise men told Tony Blair

    Months before the invasion of Iraq in 2003, experts sought to warn the PM about his plans. Here, four of them recall that day
    25 years of The Independent on Sunday: The stories, the writers and the changes over the last quarter of a century

    25 years of The Independent on Sunday

    The stories, the writers and the changes over the last quarter of a century
    Homeless Veterans appeal: 'Really caring is a dangerous emotion in this kind of work'

    Homeless Veterans appeal

    As head of The Soldiers' Charity, Martin Rutledge has to temper compassion with realism. He tells Chris Green how his Army career prepared him
    Wu-Tang Clan and The Sexual Objects offer fans a chance to own the only copies of their latest albums

    Smash hit go under the hammer

    It's nice to pick up a new record once in a while, but the purchasers of two latest releases can go a step further - by buying the only copy
    Geeks who rocked the world: Documentary looks back at origins of the computer-games industry

    The geeks who rocked the world

    A new documentary looks back at origins of the computer-games industry
    Belle & Sebastian interview: Stuart Murdoch reveals how the band is taking a new direction

    Belle & Sebastian is taking a new direction

    Twenty years ago, Belle & Sebastian was a fey indie band from Glasgow. It still is – except today, as prime mover Stuart Murdoch admits, it has a global cult following, from Hollywood to South Korea
    America: Land of the free, home of the political dynasty

    America: Land of the free, home of the political dynasty

    These days in the US things are pretty much stuck where they are, both in politics and society at large, says Rupert Cornwell
    A graphic history of US civil rights – in comic book form

    A graphic history of US civil rights – in comic book form

    A veteran of the Fifties campaigns is inspiring a new generation of activists
    Winston Churchill: the enigma of a British hero

    Winston Churchill: the enigma of a British hero

    A C Benson called him 'a horrid little fellow', George Orwell would have shot him, but what a giant he seems now, says DJ Taylor
    Growing mussels: Precious freshwater shellfish are thriving in a unique green project

    Growing mussels

    Precious freshwater shellfish are thriving in a unique green project