10 Amazing Ways Sound Is Transforming Science

When imagining the future of technology, we often miss the remarkable strides being made in the field of acoustics. Sound is rapidly becoming one of the key elements of tomorrow's innovations. Science is leveraging sound in more exciting ways than ever, and in the years ahead, we can expect to hear a lot more about its incredible potential.

10. Cooling Technology

This system was designed as a more eco-friendly alternative to conventional refrigerators. Unlike traditional models that rely on harmful chemical refrigerants, the thermoacoustic fridge utilizes inert gases like helium. If helium escapes into the atmosphere, it doesn't cause any damage, making this technology significantly greener than anything currently available. As the technology progresses, its creators hope that thermoacoustic refrigerators will eventually outperform traditional ones in terms of reliability, as they contain fewer moving parts that could fail.

9. Ultrasonic Fusion

Like many innovations, this one was stumbled upon by chance. Robert Soloff was experimenting with ultrasonic film-sealing technology when the probe he was using accidentally brushed against a Scotch tape dispenser on his desk. The unexpected result fused the two halves of the dispenser, leading him to realize that sound waves could travel along the edges and corners of rigid plastics to bond joints. Inspired by this discovery, Soloff and his team went on to develop and patent the technique known as the ultrasonic staking method.

Since that moment, ultrasonic welding has become a widely used technology across various sectors. From diapers to automobiles, it's applied wherever plastics need to be fused. Recently, the US Navy has begun testing the method to create ‘welded seams’ for its uniforms. If the fabric is a thermoplastic like nylon, ultrasonic welding can form seams that are lighter, stronger, and more insulating than those made by traditional stitching.

While companies like Patagonia and Northface have already integrated welded seams into their products, its military applications are still in the experimental phase. Typically, the technique is used for straight seams rather than those with curves, and the cost remains high. For the time being, hand-sewing remains the most affordable and versatile option.

8. Stealing Credit Card Information

Security expert Dragos Ruiu conceived this idea after observing something unusual with his MacBook Air: following an OS X installation, the computer's boot firmware updated on its own. It was infected with a powerful virus that blocked CD-ROM booting, could erase data, and make changes at will. Even after wiping the system, reinstalling the OS, and reconfiguring everything, the issue persisted. The most likely explanation for the virus's persistence was that it resided in the BIOS, enabling it to survive removal attempts. The other, more unlikely theory was that it used high-frequency sound waves transmitted between speakers and microphones to transfer data.

While this theory seems improbable, it was proven to be at least somewhat possible when a German research facility developed a method to replicate the effect. Using software designed for underwater communication, they created a malware prototype that could send data between non-networked laptops using only their speakers. During experiments, laptops were able to communicate from distances up to 20 meters (65 feet). The range could be increased by connecting infected devices to form a network, much like Wi-Fi repeaters.

The good news is that acoustic transmission is extremely slow, achieving a rate of only 20 bits per second. While this is insufficient for transferring large files, it is adequate for sending smaller data bursts such as keystrokes, passwords, credit card numbers, and encryption keys. Given that current malware can already handle these tasks faster and more effectively, it is unlikely that a new acoustic-based threat will emerge in the near future.

7. Acoustic Scalpels

Although the basic technology has existed since the late 1800s, the new scalpel was made possible by incorporating a lens coated with carbon nanotubes and a material called polydimethylsiloxane, which converts light into high-pressure sound waves. When focused enough, these sound waves generate shock waves and microbubbles that apply pressure at a microscopic scale. It has already been tested by detaching an ovarian cancer cell and drilling a 150-micrometer hole into an artificial kidney stone. The creators hope it can eventually be used for drug delivery or for eliminating small cancer tumors or plaques. The procedure may even be painless because the beam is so fine it can bypass nerve cells.

6. Charge Your Phone With Your Voice

Since sound is merely the compression and expansion of gases in the air, creating movement, it becomes a potential energy source. Researchers are exploring ways to charge your phone simply by using it—specifically when making calls. In 2011, a team in Seoul employed nano-rods of zinc oxide positioned between two electrodes to generate electricity from sound waves. This technology produced 50 millivolts from the sounds of bustling traffic. While not enough to charge most devices, London engineers managed to design a device capable of generating 5 volts—sufficient to charge a phone.

Charging phones using sound is great news for frequent talkers, but it’s also set to impact the developing world. The same thermoacoustic technology responsible for refrigerators can be applied to convert sound into electricity. The Score-Stove, which combines a cooker and fridge, captures energy from cooking with biomass fuels to produce a small amount of electricity—around 150 watts. Though modest, this is enough to provide limited power to the 1.3 billion people globally without access to electricity.

5. Transforming The Human Body Into A Microphone

The device they developed integrates a microphone with a computer. When someone speaks into the microphone, the computer records the speech as a loop, which is then converted into an inaudible signal. This signal is transmitted through a wire connected to the mic, then flows into the body of anyone holding it. The body generates a modulated electrostatic field that triggers a tiny vibration when the person touches anything. If they touch another person’s ear, the vibration is audible. The vibration can even transfer from one person to another if they are in physical contact.

4. Espionage

To achieve optimal outcomes, the algorithm needs a higher frame rate than the audio signal's frequency, which calls for a high-speed camera. For reduced results, it can still work with a regular digital camera to detect things like the number of people speaking in a room, their gender, and potentially even their identities. This breakthrough technology can be applied in fields such as forensic investigations, law enforcement, and intelligence operations. With this advancement, simply pointing a high-speed camera at a window could capture everything happening inside.

3. Touch-sensitive Holograms

Initially, this technology was designed to apply physical pressure on your skin when you make gestures to control various devices. For instance, a mechanic with greasy hands could use it to flip through a manual without getting it dirty. It's somewhat similar to the experience of flipping through physical pages on Amazon’s Kindle.

The technology relies on sound to generate vibrations that simulate the sensation of touch, and these vibrations can be adjusted for varying sensations. For example, a 4-hertz vibration feels like heavy rain, while 125 hertz gives the impression of touching foam. The only current limitation is that dogs can hear these frequencies, though the creators are working on a solution.

The device has evolved to generate virtual shapes like spheres and pyramids. However, there isn’t an actual projected shape; instead, it uses sensors to track your hand and emit sound waves in a way that mimics the shape. Though the objects currently lack detail and have minor shape inaccuracies, the designers believe that once integrated with a visible hologram, the human brain will automatically combine them into a coherent image. They aim to incorporate this technology into various products, from video games to tools enabling doctors to physically interact with objects in a CT scan.

2. Tractor Beams

For many years, scientists have endeavored to bring elements from Star Trek into the real world, particularly the tractor beam. While much of the research is centered on optical tractor beams that use heat to move objects, these advancements are limited to tiny items just a fraction of a millimeter wide. However, ultrasonic tractor beams are showing promise by successfully moving larger objects—around one centimeter in size. Although this still may seem small, the new beams possess a billion times greater force than their predecessors.

By directing two ultrasonic beams at a target, objects can be pulled towards the source of the beam by reflecting and scattering the waves in opposite directions. Even though the scientists weren’t able to create the ideal wave type for their method (known as a “Bessel beam”), they managed to replicate it sufficiently to develop a functional tractor beam. In the future, this technology could revolutionize medicine, potentially guiding objects and fluids inside the human body, allowing for precise drug delivery. Unfortunately for Star Trek fans, sound cannot travel through the vacuum of space, meaning it won’t be used to rescue any distressed ships.

1. Acoustic Cloaking

Scientists have designed a device capable of rendering objects undetectable to sound. Shaped like a peculiar pyramid full of holes, the structure modifies the path of sound waves, guiding them as if they had bounced off a flat surface. When this acoustic cloak is placed over an object on a flat surface, the object becomes inaudible from any angle.

Although it may not prevent someone from listening in on a conversation from the outside, this technology can obscure objects in areas where sound quality is critical, such as concert halls. Since the research was funded by the US military, it’s likely they have broader applications in mind. While it doesn’t trap sound, the device has the potential to shield objects from sound-based detection systems like sonar. As sound behaves similarly in water and air, acoustic cloaking could one day make submarines undetectable to sonar.