Skip to main content

Scientists use bounced lasers to determine whether a glass of water is pure

Testing Liquids at the Speed of Sound

From DIY water-testing kits to checking out the U.S. Environmental Protection Agency’s databases, there are various ways you can go about testing whether or not water is safe to drink before you elect to pour it down your throat. Scientists from the University of Missouri and Mexico’s Universidad de Guanajuato have come up with an alternative solution — and it’s a high tech doozy!

Recommended Videos

Their approach involves using a tattoo removal laser machine to flash out a series of brief bursts of light, each lasting around 10 nanoseconds. These flashes of light travel through a fiber optic cable, which is wrapped on one end with paint-on liquid electrical tape. The cable’s end is submerged in the liquid to be tested, converting the laser light into sound. The sound is recorded by a microphone, and the data analyzed in real time.

In short, it uses sonar technology to measure the purity of liquid. It does this by measuring the length of time which passes between each laser flash and the sound reaching the microphone. This allows the researchers to work out how quickly sound waves are traveling in the water — which lets them establish whether there is something in the water that is causing the sound waves to not move as fast as they should.

“This phenomenon is known as the photoacoustic effect,” Dr. Gerardo Gutiérrez Juárez at the Universidad de Guanajuato, told Digital Trends. “The photoacoustic effect is the generation of sound with light. If the PA effect is produced by a nanosecond or pulsed lasers, the frequency of generated sound is in the range of the ultrasound. … With our technology, we can measure the velocity of sound in fluids. This physical magnitude is very important because is correlated with other physical magnitudes like density, which are hard to measure.”

What the technology doesn’t do — unless some other liquid analysis technologies we’ve covered — is to tell you what is present in the liquid. It will tell you whether a liquid sample is as pure as you hope it to be, but not what is contaminating it or the concentration of this contaminant. It is a quick and easy method of forensic quality control.

A paper describing the work, titled “Laser-induced sound pinging: A rapid photoacoustic method to determine the speed of sound in microliter fluid volumes,” was recently published in the journal Sensors and Actuators, B: Chemical.

Luke Dormehl
I'm a UK-based tech writer covering Cool Tech at Digital Trends. I've also written for Fast Company, Wired, the Guardian…
Zoox recalls robotaxis after Las Vegas crash, citing software fix
zoox recall crash 1739252352 robotaxi side profile in dark mode

Amazon's self-driving vehicle unit, Zoox, has issued a voluntary safety recall after one of its autonomous vehicles was involved in a minor collision in Las Vegas. The incident, which occurred in April 2025, led the company to investigate and identify a software issue affecting how the robotaxi anticipates another vehicle’s path.
The recall, affecting 270 Zoox-built vehicles, was formally filed with the National Highway Traffic Safety Administration (NHTSA). Zoox said the issue has already been addressed through a software update that was remotely deployed to its fleet.
Zoox’s robotaxis, which operate without driving controls like a steering wheel or pedals, are part of Amazon’s entry into the autonomous driving space. According to Zoox’s safety recall report, the vehicle failed to yield to oncoming traffic while making an unprotected left turn, leading to a low-speed collision with a regular passenger car. While damage was minor, the event raised flags about the system’s behavior in complex urban scenarios.
Establishing safety and reliability remain key factors in the deployment of the relatively new autonomous ride-hailing technology. Alphabet-owned Waymo continues to lead the sector in both safety and operational scale, with services active in multiple cities including Phoenix and San Francisco. But GM’s Cruise and Ford/VW-backed Argo AI were forced to abandon operations over the past few years.
Tesla is also expected to enter the robotaxi race with the launch of its own service in June 2025, leveraging its Full Self-Driving (FSD) software. While FSD has faced heavy regulatory scrutiny through last year, safety regulations are expected to loosen under the Trump administration.
Zoox, which Amazon acquired in 2020, says it issued the recall voluntarily as part of its commitment to safety. “It’s essential that we remain transparent about our processes and the collective decisions we make,” the company said in a statement.

Read more
Mitsubishi’s back in the EV game—with a new electric SUV coming in 2026
mitsubishi bev 2026 momentum 2030 line up

Mitsubishi is officially jumping back into the U.S. electric vehicle scene—and this time, it’s not just dipping a toe. The company confirmed it will launch a brand-new battery-electric SUV in North America starting in summer 2026, marking its first fully electric model here since the quirky little i-MiEV left the stage back in 2017.
The new EV will be a compact crossover, and while Mitsubishi is keeping most of the juicy details under wraps, we do know it’ll be based on the same next-gen platform as the upcoming Nissan Leaf. That means it’ll ride on the CMF-EV architecture—the same one underpinning the Nissan Ariya—which supports ranges of up to 300+ miles. So yeah, this won’t be your average entry-level EV.
Designed in partnership with Nissan, the new model will be built in Japan and shipped over to U.S. shores. No word yet on pricing, battery size, or even a name, but Mitsubishi has made it clear this EV is just the beginning. As part of its “Momentum 2030” plan, the company promises a new or updated vehicle every year through the end of the decade, with four electric models rolling out by 2028. And yes, one of those might even be a pickup.
Mitsubishi says the goal is to give customers “flexible powertrain options,” which is marketing speak for: “We’ll have something for everyone.” So whether you're all-in on electric or still into gas or hybrid power, they're aiming to have you covered.
This mystery EV will eventually sit alongside Mitsubishi’s current U.S. lineup—the Outlander, Outlander PHEV, Eclipse Cross, and Outlander Sport—and help the brand move beyond its current under-the-radar status in the electric world.
In short: Mitsubishi’s finally getting serious about EVs, and if this new SUV lives up to its potential, it might just put the brand back on your radar.

Read more
Toyota unveils 2026 bZ: A smarter, longer-range electric SUV
toyota bz improved bz4x 2026 0007 1500x1125

Toyota is back in the electric SUV game with the 2026 bZ, a major refresh of its bZ4X that finally delivers on two of the biggest demands from EV drivers: more range and faster charging.
The headline news is the improved driving range. Toyota now estimates up to 314 miles on a single charge for the front-wheel-drive model with the larger 74.7-kWh battery—about 60 miles more than the outgoing bZ4X. All-wheel-drive variants also get a boost, with up to 288 miles of range depending on trim.
Charging speeds haven’t increased in terms of raw kilowatts (still capped at 150 kW for DC fast charging), but Toyota has significantly improved how long peak speeds are sustained. With preconditioning enabled—especially helpful in colder weather—the new bZ can charge from 10% to 80% in about 30 minutes. Also new: Plug and Charge support for automatic payment at compatible stations and full adoption of the North American Charging Standard (NACS), meaning access to Tesla Superchargers will be standard by 2026.
Under the hood, or rather the floor, Toyota has swapped in higher-performance silicon carbide components to improve efficiency and power delivery. The AWD version now produces up to 338 horsepower and sprints from 0–60 mph in a brisk 4.9 seconds.
Toyota didn’t stop at just the powertrain. The exterior has been cleaned up, with body-colored wheel arches replacing the black cladding, and a sleeker front fascia. Inside, a larger 14-inch touchscreen now houses climate controls, giving the dash a more refined and less cluttered appearance. There’s also more usable storage thanks to a redesigned center console.
With the 2026 bZ, Toyota seems to be responding directly to critiques of the bZ4X. It’s faster, more efficient, and more driver-friendly—finally bringing Toyota’s EV efforts up to speed.

Read more