Japanese scientists have been successful in moving an object in a three-dimensional space through a complex system of acoustic levitation, surpassing previous research endeavors that lifted the objects in two dimensions.
In order to move expanded polystyrene particles of 0.6 mm and 2 mm in diameter, the Japanese scientists at the University of Tokyo and the Nagoya Institute of Technology had to place the objects inside a complex set-up of four arrays of speakers.
Using a refinement of the existing technology of sound wave management, bubbles, a screw and a tiny piece of wood were airlifted and moved around in all direction within the experiment’s confines.
Ever wanted to make an object float? You don't need magic; you just need science.
Researchers have used the power of sound to levitate objects and even move them around in midair. The findings could have huge implications for manufacturing processes, but are also just plain cool.
Researchers have been able to levitate small objects for years, including insects and fish. But this latest effort is a bit different; the levitated items can actually be moved around in midair. Accomplishing this feat, though, wasn't easy. The scientists had to be extremely precise in their use of sound in order to cause the objects to move.
Like other types of waves, sound waves exert pressure when they hit a surface. Usually, the effects of this pressure are too small to notice, according to The Washington Post. If you crank up the intensity of these waves high enough, though, you can create enough pressure to counteract the force of gravity. This, in turn, can make an object float.
You might imagine that the sound would be loud to humans, potentially making the process impractical. But that is, surprisingly, not the case. While the researchers did crank up the intensity to about 160 decibels, which is louder than standing near a rocket launch, they also modified the pitch. Instead of a blasting roar, the sound was instead more like a dog whistle; this caused the researchers to be unaffected by the noise.
In order to actually move objects, the researchers had to employ a different type of technique. They designed tiny transducers that were powerful enough to levitate objects but small enough to be packed closely together. By turning one transducer off while the one next to it slowly turned on, they were able to make objects float and move in midair, according to LiveScience.
"For the first time, you can move matter in a very controllable yet contactless manner," said Dimos Poulikakos of the Swiss Federal Institute of Technology, in an interview with NewScientist.
The new method could have quite a few practical uses--unlike the ability to simply levitate an object in one position. It could allow researchers to mix fluids in instances where contamination is an issue, which could be extremely useful for the pharmaceutical industry.
The findings are published in the journal Proceedings of the National Academy of Sciences.
Want to see the levitation for yourself? Check out the videos below,
Those who have been through combat know that post-traumatic stress disorder (PTSD) can be triggered by sounds as benign as thunder, taking them back to experiences on the battlefield that would rather be forgotten.
The same is true of others who have been through trauma – deep emotions can be set off by sounds that are non-traumatic in their essence, but result in feelings of great fear or anxiety. Until now, scientists didn’t know what caused this in the brain.
A team of researchers at the Perelman School of Medicine at the University of Pennsylvania has discovered how sound can be translated in the brain and distorted to dredge up fearful emotions. The senior author of the study, which was published in Nature Neuroscience, Maria N. Geffen, PhD, states: “Emotions are closely linked to perception and very often our emotional response really helps us deal with reality.” This also means that emotions can alter our experience of reality. She goes on to say:
“ . . .the fear response helps you escape potentially dangerous situations and react quickly. But there are also situations where things can go wrong in the way the fear response develops. That’s what happens in anxiety and also in PTSD — the emotional response to the events is generalized to the point where the fear response starts getting developed to a very broad range of stimuli.”
To break down what happens in the brain, what we hear is attached to our emotions through the auditory cortex, a part of the brain that mitigates auditory plasticity. Utilizing mice to investigate how hearing different frequencies were linked to emotional learning, or Pavlovian conditioning, scientists observed what happened in this particular area of the brain. The mice were observed to see how certain sounds would cause them to have a particular emotional response when repeatedly exposed to a sound that was either ‘safe’ or ‘potentially dangerous.’ The scientists in charge of the study, Mark Aizenberg, PhD and Geffen, designed a series of tasks meant to teach increasing levels of emotional discrimination.
What became interesting while observing the rats as they responded to the scientists’ experiments was how their emotional perception affected their ability to hear properly. A direct link was established through this observation, to the connection of sound and perception of the world. This has not been previously documented in other studies.
Geffen explains:
“The animals presented with sounds that were very far apart generalize the fear that they developed to the danger tone over a whole range of frequencies, whereas the animals presented with the two sounds that were very similar exhibited specialization of their emotional response. Following the fine conditioning task, they figured out that it’s a very narrow range of pitches that are potentially dangerous.”
She continues:
“There was a relationship between how much their emotional response generalized and how well they could tell different tones apart,” says Geffen. “In the animals that specialized their emotional response, pitch discrimination actually became sharper. They could discriminate two tones that they previously could not tell apart.”
All of this was mediated by the auditory cortex. While the specific of emotional learning originate in the amygdala, and sub-cortical areas of the brain, Geffen explained how their hypothesis is that amygdala and cortex alter “subcortical auditory processing areas”. She said that the sensory cortex, while responsible for the changes in frequency discrimination, is not necessary for the development of emotional responses. This is a puzzle.
Studies will now be aimed at understanding exactly how the emotional learning takes places in victims of PTSD, where generalized fear is the norm. Once the link between auditory plasticity and generalization of fear is understood more fully, it might be possible to retrain the brain to be more fearless with a different set of sounds, or new emotional programming.
