Scientists Crack the Case of 'Screeching' Scotch Tape (arstechnica.com) 30
The screeching sound that Scotch tape makes when you rip it off a surface -- that fingernails-on-a-chalkboard noise most people try not to think about -- is produced by shock waves from micro-cracks that travel across the peeling tape at supersonic speeds, according to a new paper published in Physical Review E.
Researchers led by Sigurdur Thoroddsen of King Abdullah University in Saudi Arabia used simultaneous high-speed imaging and synchronized microphones to capture both the propagating fractures and the sound waves they generate in the surrounding air. The team's earlier work, in 2010, had identified a sequence of transverse cracks racing across the width of the adhesive during peeling, and a 2024 follow-up established a direct correspondence between those cracks and the screeching sound, but neither study pinpointed a mechanism.
The new findings show that a partial vacuum forms between the tape and the surface as each crack opens, and because the crack moves faster than air can rush in to fill the void, the vacuum travels along until it reaches the tape's edge and collapses into the stationary air outside, producing a discrete sound pulse.
Researchers led by Sigurdur Thoroddsen of King Abdullah University in Saudi Arabia used simultaneous high-speed imaging and synchronized microphones to capture both the propagating fractures and the sound waves they generate in the surrounding air. The team's earlier work, in 2010, had identified a sequence of transverse cracks racing across the width of the adhesive during peeling, and a 2024 follow-up established a direct correspondence between those cracks and the screeching sound, but neither study pinpointed a mechanism.
The new findings show that a partial vacuum forms between the tape and the surface as each crack opens, and because the crack moves faster than air can rush in to fill the void, the vacuum travels along until it reaches the tape's edge and collapses into the stationary air outside, producing a discrete sound pulse.
Scotch tape (Score:1)
The sound doesn't bother me half as much as packing tape.
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The glue on the packing tape smells a lot worse than the tape screeches.
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Re:Scotch tape (Score:4, Insightful)
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I suggest using X-Ray radiation from said tape (see below for method)
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Then I suggest you come up with a better way to tidy one's nose hair!
I use a Dremel tool.
Pickup Lines. (Score:5, Funny)
(Scientist in a bar) "Damn right baby. I know how to handle simultaneous high-speed imaging and synchronized microphones to capture both the propagating fractures and the sound waves they generate in the surrounding air."
(Woman) "Mmmm. And what's that for?"
(Scientist) "Ninjas wrapping Christmas presents."
Good try... (Score:4, Funny)
The sound is actually caused by the cracks temporarily abrading the fabric of reality, which lets through the sound of the Langoliers gnawing at the timeline.
Re: (Score:3)
I thought it was turtles all the way down - possibly taped together?
I was more interested by the radiation (Score:5, Funny)
I was more interested by the radiation emitted. Supposedly the cracking bonds of the adhesive release Xrays. People even took xrays of stuff on a youtube channel somewhere by ripping tape fast over those xray imaging films and got a weak picture.
Makes me think twice before ripping it fast. Going slow made far less xrays.
Re:I was more interested by the radiation (Score:4, Interesting)
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Not if you need that vacuum chamber.
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There have been university-level demonstrations where people unroll Scotch tape in a vacuum chamber and generate enough X-rays to image people's finger bones.
And as a bonus, the vacuum will pretty effectively stifle the screeching sound of the tape being peeled off!
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Well not in *my* movie!!!!!
-- Georges Lucas
Re:I was more interested by the radiation (Score:4, Informative)
Makes me think twice before ripping it fast. Going slow made far less xrays.
You missed something. I think if you're standing in a vacuum (which is necessary for this to work) you probably have bigger concerns than some xrays (mainly the ability to breath). Scotch tape is known to give of slight amounts of visible light when pulled really quickly in an atmosphere, but it's essential for all those experiments you've seen to work in a very low vacuum. VERY low vacuum. Plenty of people have tried duplicating the experiment on Youtube and found that run of the mill vacuum chambers aren't sufficient, you need something well below 0.1torr to generate x-rays (so you're looking at mid triple digit $$$ on your vacuum chamber).
And even then you need to unroll at high speed and sustain that speed (what do you need that much tape for) in the end only to have enough x-rays to take a very long exposure of your finger using sensitive tape.
If you sit down in your vacuum right up against that tape, and use a power drill to quickly tear off 100 rolls of Scotch tape, you'll have still absorbed less radiation than a pilot does on a typical workday.
Radiation is like electricity. It can't be seen, it's not easy to understand, so people are irrationally afraid of it.
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Radiation is like electricity. It can't be seen, it's not easy to understand, so people are irrationally afraid of it.
I think it is because it can affect people without them actually having to be touched. I've worked with radioactive materials, and just consider them poisons with a little reach. Beats hell out of the irrational fear.
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Just think, those people who protest tritium exit signs don't think twice about ripping scotch tape fast.
cavitation (Score:3)
Sounds like cavitation, but not in a liquid.
Re:cavitation (Score:4, Insightful)
That's not at all far off and tape adhesive is a high viscosity liquid.
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"Engineers call the glue in Scotch tape a pressure-sensitive adhesive. It does not stick by forming chemical bonds with the material it is placed on, says Alphonsus Pocius, a scientist at the 3M Corporate Research Materials Laboratory in St. Paul, Minn. Instead applied pressure forces the glue to penetrate the tiniest microscopic irregularities on the material’s surface. Once there, it will resist coming back out, thus keeping the tape stuck in place. The glue “has to be halfway between liquid a
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I wonder how that works with graphene? Lay a strip of Scotch tape on a chunk of graphene and peel it off and you have a one atom thick two dimensional layer of graphene.
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"Engineers call the glue in Scotch tape a pressure-sensitive adhesive. It does not stick by forming chemical bonds with the material it is placed on, says Alphonsus Pocius, a scientist at the 3M Corporate Research Materials Laboratory in St. Paul, Minn. Instead applied pressure forces the glue to penetrate the tiniest microscopic irregularities on the material’s surface. Once there, it will resist coming back out, thus keeping the tape stuck in place. The glue “has to be halfway between liquid and solid,” Pocius explains: fluid enough to spread under pressure but viscous enough to resist flowing."
https://www.scientificamerican... [scientificamerican.com]
My take is still cavitation.
Yes, I'd be shocked if it wasn't cavitation. Just in a liquid with an extremely high Reynolds number.
Is this ... (Score:5, Funny)
Asking for a friend.
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Asking for a friend.
Rip the duct tape off your friend's mouth and ask them.
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Asking for a friend.
Hey, I didn't want to, but she said it would be fun.
How much contributed by the cellophane itself? (Score:2)
Did they filter the difference between the adhesive fractures and the tape? Sorry, who actually RTFA?
In tape (Score:3)
no one can hear you scream. I'll see myself out.