Watch Scientists Levitate a Golf Ball-Sized Object With a Real-Life Tractor Beam

Monday, 15 August 2016 - 12:33PM
Physics
Monday, 15 August 2016 - 12:33PM
Watch Scientists Levitate a Golf Ball-Sized Object With a Real-Life Tractor Beam
Star Trek introduced the idea of a tractor beam, a beam of light that can pull objects towards it, with "Beam me up, Scotty!", and scientists have been trying to make a real-life equivalent ever since. The closest they've come, however, is an acoustic tractor beam, which uses sound waves rather than light waves, and which just levitated a golf ball-sized object for the first time.



Acoustic tractor beams first came into prominence in 2014, when scientists from the University of Dundee discovered that sound waves could lift small objects, like water droplets or miniature spheres. But researchers who studied this new technology believed that it might be impossible to extrapolate it to large-scale objects. The ability of the sound waves to lift an object depends on their frequency; the lower the frequency of the sound waves, the heavier the object that could be lifted. This means that the necessary sound waves could be dangerous to humans and, according to the initial research, the largest object that could be levitated was 4mm long.

We still might not be able to "beam up Scotty" yet, but scientists have managed to lift a larger object using lower-frequency acoustic waves. In fact, the object is 3.6 times larger than the acoustic wavelength, which scientists thought would be impossible. In order to accomplish this, the researchers modified the traditional method, which involves trapping the object in the pressure node of a standing wave, and instead created standing waves between three transducers and the sphere.

Acoustic Levitation

Opening quote
"In our paper, we demonstrate that we can combine multiple ultrasonic transducers to levitate an object significantly larger than the acoustic wavelength," co-author Marco Andrade from the University of São Paulo in Brazil told Phys.org. "We could increase the maximum object size from one quarter of the wavelength to 50 mm, which is approximately 3.6 times the acoustic wavelength."
Closing quote

Using this technique, the researchers were able to levitate the object at 7mm, approximately twice the size of the acoustic wavelength. There are still several limitations, most notably that the device is only capable of levitating rather than continuously moving the object, but they hope to discover new methods for contactless manipulation of objects in future research. 

Opening quote
"At the moment, we can only levitate the object at a fixed position in space," Andrade said. "In future work, we would like to develop new devices capable of levitating and manipulating large objects in air."
Closing quote

Via Science Alert

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