Acoustic levitation: how sound lifts objects, and what's new

Acoustic levitation uses sound you cannot hear to hold small objects in mid-air: a bead, a drop of liquid, even a tiny chemistry experiment that never touches a container. It sounds like science fiction, yet the basic version is now a weekend build, and in 2025 and 2026 researchers pushed it much further: floating objects nearly 40 cm away from the speakers, and keeping several levitated particles apart for the first time.

Why it matters: anything that touches a surface can be scratched, contaminated or changed by it. Holding a sample with sound alone opens doors for medicine, materials science, 3D displays and labs that handle dangerous substances. Here is how it works, what it is already used for, and what the newest results change.

How sound can lift things

Sound is a wave of tiny pressure changes travelling through the air. Most acoustic levitators use ultrasound at 40 kHz, about twice as high as the highest note a young person can hear, so the device is silent to us even though the sound inside is very intense.

The classic trick is a standing wave. Point a speaker at a reflector, or two speaker arrays at each other, and the waves going up and coming down overlap. They build a pattern that stays still in space, with quiet spots called nodes and loud spots called antinodes. Small, light objects get pushed towards the nodes and sit there, held by the sound pressure around them like a marble resting in a dip. At 40 kHz the wavelength in air is about 8.6 mm, so the “seats” are only a few millimetres apart, which is why levitated objects are usually small: polystyrene beads, droplets, tiny chips of material.

Diagram-like illustration of a standing sound wave between a speaker and a reflector, with small spheres resting in the quiet gaps between the wave bands. — A standing wave has quiet spots, called nodes, every few millimetres: that is where small objects sit · Illustration by DIGITAL WOXTER TECHNEWS.

From one floating bead to tractor beams

For decades levitators were single-axis tubes: one trap, one object, fixed in place. The big leap came from phased arrays, grids of many small ultrasonic speakers whose timing a computer controls one by one, like an orchestra playing slightly out of step on purpose. By shaping the sound field, researchers can move the traps around in 3D.

In 2015 a team from the universities of Bristol and Sussex used an array of 64 miniature speakers at 40 kHz to grab and move polystyrene beads up to 4 mm across with a one-sided “sonic tractor beam”, publishing the work in Nature Communications (University of Bristol). The sound fields took shapes the authors described as tweezers, twisters and bottles.

In 2019 a Sussex team turned the idea into a screen. Their multimodal acoustic trap display used two arrays of 256 speakers to fling a single coloured bead around so fast that our eyes see a floating 3D shape, drawn in less than a tenth of a second. The same sound field also produced audible sound and something you could feel with your fingers, as reported in Nature.

New in 2025-2026: more reach, more particles

Levitation 40 cm away, from one side only

Most strong levitators need speakers on two sides, which boxes the object in. Single-sided traps are more practical, but their grip weakens quickly with distance. In August 2026, researchers from the University of Tsukuba and the University of Bristol reported in Physical Review Letters that a special narrow beam, a zero-order Bessel beam, can hold a 1.5 mm polystyrene bead up to 397 mm from a 16 × 16 grid of 40 kHz transducers. That is about six times the previous single-sided record of 67 mm (University of Bristol). Unusually, the object sits in the loud core of the beam rather than in a quiet node, and the team also levitated several objects at once and held them beyond obstacles. The researchers see uses in automated experiments, 3D displays and handling fragile or hazardous materials.

Keeping floating particles apart

Here is a problem you might not expect: put several particles in the same sound field and they attract each other and collapse into one clump. Physicists at the Institute of Science and Technology Austria (ISTA) found a fix by giving the particles an electric charge, so their electric push balances the sound’s pull. Published in PNAS, the method produced fully separated groups, clumps, or a mix, and the team could switch between them by bouncing the particles off a charged reflector plate (Phys.org / ISTA). They even saw pairs of particles that chase each other, an effect predicted before but never observed because the particles always clumped. The authors point to materials science and micro-robotics as future uses.

What acoustic levitation is used for today

Medicines: scientists at Argonne National Laboratory levitated drops of drug solutions so they dried without ever touching a container. Contact with a container wall tends to push a drug into crystals; without it, the drug can stay amorphous (a disordered form that usually dissolves better in the body), as reported by ScienceDaily and Universe Today. It is still a lab method that works on small amounts.
Materials research: “containerless processing” lets researchers dry, melt, cool and study samples with no wall to contaminate them or make crystals form early. The Argonne levitator itself was originally designed for NASA to simulate microgravity.
Displays and touch: levitated beads can draw floating 3D images, and the same speaker arrays can create mid-air touch sensations, as the Sussex display showed.
Lab automation: long-range, one-sided traps like the 2026 Bessel-beam design could move fragile or dangerous samples between stations without grippers.

The limits

Acoustic levitation is not about to lift people or cars. The objects are small and light, typically millimetre-sized beads and drops, because the traps are only a few millimetres across and the force is gentle. Strong sound fields also need power and careful control, and an air draught or a hand in the wrong place can knock a sample out. Most of the exciting results above are lab demonstrations, not products yet.

How to try it yourself

You can build a levitator at home. TinyLev, published in 2017 by researchers at Bristol, uses two 3D-printed bowls holding 36 small 40 kHz transducers each, an Arduino Nano and a common motor-driver board; the paper gives about 20 V and 10 W of power, and IEEE Spectrum built one from a kit. The parts list, printable files and instructions are public, and kits exist too. Start with tiny polystyrene beads or water droplets, keep the power low, and watch them hang in the air. It is one of the most magical science projects you can put on a desk.

Want to go deeper before you build? The white paper by Nadia Weronika Brzostowicz walks through building two different acoustic levitators, compares them and looks at practical uses: a great companion for a first project.