mix in corn amylum and pee gain for a crowd - pleasing raw material of science demos . The result substance looks like a liquid , buthardens instantly when you punch it — in fact , it ’s possible torun across a kitty of the stuff . Now physiciststhink they ’ve figured outjust what ’s hold out on when this unusual material switches from a liquid to a solid , hopefully ending a long - running debate . They described their findings ina new paper inPhysical Review Letters .
The concoction goes by many name , but the most common one is “ oobleck , ” a nod to the classic Dr. Seuss story , Bartholomew and the Oobleck . It ’s really simple to make your own . Just combine two cups of corn starch — add three drops of green food coloring if you desire that snot - like Seuss burden — and bit by bit mix in enough water to create a mixture that resemble pancake batter ( usually about equal parts starch and water supply ) .
https://gizmodo.com/what-happens-when-you-shoot-a-golf-ball-at-a-balloon-fi-1769486275
It ’s a all right instance of a so - called “ non - Newtonian fluid . ” Isaac Newton described the property of an “ ideal liquid state ” back in the 17th 100 , one of which isviscosity , slackly delineate as how much friction / resistance there is to flow in a given substance . Oobleck is the opposite of an idealistic liquid state . As Iwrote back in 2007 :
The friction arise because a flowing liquid is essentially a series of layer slide past one another . The faster one layer slides over another , the more opposition there is , and the tiresome one layer slue over another , the less resistance there is . Anyone who ’s ever stuck their arm out of the window of a moving car can attest that there is more air resistance the faster the car is motivate ( air is technically a fluid ) .
That ’s the basic principle . But the world is not an ideal place … . In Newton ’s ideal fluid , the viscosity is mostly pendant on temperature and force per unit area : body of water will continue to flow — i.e. , act like water — regardless of other effect acting upon it , such as being stirred or motley . In a non - Newtonian fluid [ like oobleck ] , the viscosity vary in response to an apply melody or shearing military unit , thereby straddling the boundary between liquid and square behavior .
have the 11th Doctor Who , Matt Smith , demonstrate :
That ’s the grownup - picture explanation , but physicist have been arguing for decades about exactly what ’s start on at the small ordered series , because experimentation and data processor modeling study have n’t agreed . From a physics standpoint , we ’re blab out about microscopical particles suspended in liquid ( colloids ) . On one side are physicist who think that friction between those suspended micro atom lock them in lieu to resist flow like a liquidity .
On the other are those who favor a hydrodynamical account : the micro particles are drive nigh together with the encroachment , and the liquid between them is forced out , producing resistance that slows them down sufficiently that they concisely interlace into so - name “ hydroclusters . ”
So who is good ? Physicists at Georgetown University and the National Institute of Standards and Technology call up they have the answer : both side are correct . The two competing possibility are really complementary . So it ’s kind of a win - win for physics .
“ This transition demonstrates that shear thickening is driven primarily by frictional contacts , with hydrodynamic forces play a supporting role at lower concentrations of corpuscle , when mixtures are less dense , ” lead author John Royer of NISTsaid in a program line .
Okay , but why should we care ? These kinds of effects “ dictate how much hooey you’re able to move and at what speed , ” Centennial State - author Daniel Blair , a Georgetown University physical science prof , said in a statement . “ In the chemical substance processing industriousness , you ’re looking for the most efficient style to move something through a pipe , without breaking a ticker . To do that , you want to know as much as you’re able to about fleece thickening so you’re able to command it . ”
Shear - thickening fluids are already being used on prototype bullet - proof vests and sporting equipment , because their predisposition to encroachment means they can good absorb the vitality of a gamey - velocity projectile or hard shock , while still being flexible enough to wear well . The US and Canadian skiers in the 2006 Winter Olympics wear out asimilar form of “ impudent armor”manufactured by a British company called d3o Labs .
[ NIST , Physical Review Letters ]
PhysicsScience
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