Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

Watch: Death Valley’s Mysterious ‘Sailing Stones’ Inspire Ice Slingshot That Propels Frozen Discs Without External Force
The Debrief ^ | August 17, 2025 | Christopher Plain

Posted on 08/19/2025 12:43:02 PM PDT by Red Badger

Virginia Tech engineers have designed an “ice slingshot” that can propel frozen disks of water across a flat, grooved surface without any external force. Previous experiments have demonstrated a similar forceless propulsion of dry ice on a layer of vapor. However, the novel ice slingshot produces a similar motion without harmful CO2.

The Virginia Tech team suggests their approach could lead to the development of energy generation devices or micro-transportation systems and potentially offer unique de-icing approaches.

In an email to The Debrief, Associate Professor Jonathan Boreyko from Virginia Tech’s School of Mechanical Engineering explained the process relies on a scientific concept known as ‘Laplace pressure.’ As a result, he said, “We’re calling it a ‘Laplace slingshot.”

“For the general audience, a simple ‘ice slingshot’ will suffice,” the professor added.

According to the study detailing the research team’s findings, scientists previously defined how droplets of water deposited on a superheated surface could levitate on a cushion of their own vapor. The team writes that several previous studies have demonstrated that these ‘Leidenfrost’ droplets can “self-propel across asymmetric sawtooth structures.” They also note that similar behavior has been observed with rigid blocks of sublimating dry ice, which is melting frozen CO2.

The effect has been achieved using “alternative geometries,” including V-shaped, herringbone groove patterns carved into a surface. Unlike superheated surfaces, these “Leidenfrost ratchets” can produce self-propulsion by the addition of these simple geometric patterns, a benefit the team describes as “particularly advantageous due to its ease of fabrication and Modeling.”

While there is a lack of detailed scientific data on the movement of ice due to surface geometry, the team highlights the mystery of Racetrack Plaza in Death Valley, where boulders have long been observed to mysteriously move across the desert seemingly on their own.

The Death Valley’s msyterious “sailing stones” seen near Racetrack Playa (Image Credit: Jon Sullivan)

========================================================================

Several theories have been proposed previously to explain this phenomenon. However, the team explained that video evidence captured in 2014, combined with scientific analysis, showed that the boulders were raised up on extremely thin sheets of ice made from water that resisted seeping into the desert’s hard surface and transported at speeds of 2 to 5 meters per minute over distances of “∼10−100 m.”

Some boulders have been reportedly witnessed moving in concert, resulting in the “racetrack” nickname. Still, much of that motion is attributed to winds pushing the floating boulders across the desert surface.

Inspired by these examples, the Virginia Tech experimental team, led by Ph.D. student Jack Tapocik working in Boreyko’s Nature-Inspired Fluids and Interfaces Lab, tested whether ice sheets placed on a grooved surface would be able to self-propel without any external force, including wind.

Testing an Ice Slingshot

The study’s “control” test case involved placing ice disks on a level surface without any etched patterns. Boreyko told The Debrief, when the team put ice disks on a featureless, smooth surface, “there was no longer any directionality.” Where the Racetrack Plaza’s boulders could achieve wind-assisted motion, the laboratory ice disks simply floated on their melting ice but did not move in any specific direction.

Next, the team etched a test surface with grooves of either 0.25mm or 0.5 mm deep in a herringbone pattern. Unlike some advanced materials applications that require expensive lasers or other specialized equipment to alter the test bed’s surface geometry, Boreyko told The Debrief his process was relatively straightforward and inexpensive.

“It was just basic milling in a machine shop, nothing fancy!” he said.

When the team placed ice disks on their etched aluminum surface, the meltwater that formed beneath them flowed along the surface channels in a uniform direction like guides. According to Tapocik, this directional meltwater flow “carried the ice disk along with it.”

“A good analogy is tubing on a river except here, the directional channels cause the flow instead of gravity,” the experimental scientist explained.

Because the motion is similar to Leidenfrost droplets moving on their own vapor, Boreyko told The Debrief that the grooved surface “can be called an ‘ice ratchet’”

Curious what would happen if they treated the etched aluminum with a superhydrophobic coating, the team conducted an additional set of experiments. Although the team suspected that the coating would simply accelerate the pace of the ice treatment, the experiments yielded an unexpected result.

VIDEO AT LINK...................

First, because the hydrophobic coating caused the meltwater from underneath the ice disk to move faster than the untreated surface, the disks initially became anchored in place. However, the team writes, after enough time has passed for the meltwater to generate a large puddle in front of the ice disk, the resulting difference in Laplace pressure “suddenly slingshots the ice across the surface” at a speed comparable to that of previously established Leidenfrost ratchets. As a result of this ‘pause and release’ of the ice disks on a treated and etched surface, the Virginia Tech researchers named the device an ice slingshot.

“By rectifying the flow of the underlying meltwater, we achieve self-propulsion of the solid without resorting to an external force (i.e., no wind flow),” they explained.

Technological Applications When asked about potential applications of the technology underlying the ice slingshot, Boreyko told The Debrief that energy generation devices could, theoretically, tap into the small but measurable force to provide small amounts of electricity.

“We already know that dry ice (CO2) that self-propels on its vapor in a circular motion can generate energy by turning an attached turbine,” the professor explained. “By the same reasoning, we could generate energy with self-propelled melting bodies like ice.”

Boreyko also noted that such a theoretical system would replace “expensive and toxic” CO2 with H20, expanding its potential applications. The researcher conceded that the rotation speed of an energy generator based on the Laplace pressure ice slingshot concept would be smaller than that of CO2-based devices. However, he also emphasized the other potential benefits of the discovery.

“In short, we expect our technology could be a cheaper means of generating energy, albeit less energy than with dry ice,” Boreyko said.

Another potentially immediate, low-cost application of ice slingshot technology involves de-icing of surfaces, such as airplane wings, windows, and buildings. To test the idea, Boreyko told The Debrief his team wants to “grow” frost on their superhydrophobic grooves to see if Laplace pressure can “slingshot (it) off the surface” once it has partially melted.

“If this works, it would dramatically increase the speed and energy efficiency of defrosting,” he concluded.

The study “Self-Propelled Ice on Herringbones” was published in ACS Applied Materials & Interfaces.


TOPICS: Outdoors; Science; Weather; Weird Stuff
KEYWORDS: iceicebaby; physics; science

1 posted on 08/19/2025 12:43:02 PM PDT by Red Badger
[ Post Reply | Private Reply | View Replies]

To: Red Badger
However, the novel ice slingshot produces a similar motion without harmful CO2.

Stopped right there.

2 posted on 08/19/2025 12:45:03 PM PDT by E. Pluribus Unum (Democrats are the Party of racism, anger, hate and violence.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Red Badger
However, the novel ice slingshot produces a similar motion without harmful CO2.

Earth to whomever: The evil CO2 was already with us when somebody compressed it into a solid.

3 posted on 08/19/2025 12:51:59 PM PDT by Carry_Okie (The tree of liberty needs a rope.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: Red Badger

Having visited the Racetrack a couple of times, the wind there can be pretty intense. With the slightest bit of water, rocks could act as sails and move along the lakebed. At least that is what it looked like to me.

And, Death Valley is hot and well under sea level…but it is not without water. I’ve been in the park after a rain storm. Some of the ground gets very slippery.


4 posted on 08/19/2025 12:54:33 PM PDT by Vermont Lt
[ Post Reply | Private Reply | To 1 | View Replies]

To: E. Pluribus Unum; dfwgator

Yep

Trees 🎄🎄🌳🌳🎄🎄🌳🌳🎄🎄
were not interviewed

Nor plants 🌿🪴🌼🌿🌱🪴🌼

Of course if they talked...

Or sang...cue dfwgator


5 posted on 08/19/2025 12:58:14 PM PDT by SaveFerris (Luke 17:28 ... as it was in the Days of Lot; They did Eat, They Drank, They Bought, They Sold ......)
[ Post Reply | Private Reply | To 2 | View Replies]

To: Red Badger
“expensive and toxic” CO2"

These must be the extra brilliant scientists.

6 posted on 08/19/2025 1:08:26 PM PDT by TangoLimaSierra (⭐⭐To the Left, The Truth is Right Wing Violence⭐⭐)
[ Post Reply | Private Reply | To 1 | View Replies]

To: E. Pluribus Unum
What is wrong with you guys???

CO2 isn't just harmful!
CO2 is evil!!!!
CO2 will result in the instantaneous death and destruction of everything that is good!!!!

Ahhh! Ahhh! AHHHHHHHHHHHHHHHHHH!!!

7 posted on 08/19/2025 1:08:43 PM PDT by z3n (Kakistocracy)
[ Post Reply | Private Reply | To 2 | View Replies]

To: z3n

How dare you!


8 posted on 08/19/2025 1:10:25 PM PDT by E. Pluribus Unum (Democrats are the Party of racism, anger, hate and violence.)
[ Post Reply | Private Reply | To 7 | View Replies]

To: Red Badger

"Let's see...'turn Left at Albuquerque'..."

9 posted on 08/19/2025 1:27:08 PM PDT by PLMerite ("They say that we were Cold Warriors. Yes, and a bloody good show, too. 😁 " - Robert Conquest )
[ Post Reply | Private Reply | To 1 | View Replies]

To: Vermont Lt
Having visited the Racetrack a couple of times, the wind there can be pretty intense. With the slightest bit of water, rocks could act as sails and move along the lakebed. At least that is what it looked like to me.

And, Death Valley is hot and well under sea level…but it is not without water. I’ve been in the park after a rain storm. Some of the ground gets very slippery.

The thing is the Racetrack in Death Valley sits at over 3,700 feet in elevation in the Panamint Mountains.

10 posted on 08/19/2025 4:32:39 PM PDT by Inyo-Mono
[ Post Reply | Private Reply | To 4 | View Replies]

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson