Making A Wax Motor For Micrometer-Level Control

November 4, 2026 by Maya Posch 12 Comments

Although not very glamorous, wax motors are a fairly common type of linear actuator. They use the thermal response of waxes and the resulting volumetric expansion or reduction to create a relatively fast, smooth, and highly predictable actuator that can work for decades. They can often be found operating valves and things like the door mechanisms of washing machines. As [BubsBuilds] demonstrates in a recent video, you can even build your own wax motor for very precise control.

Here simple paraffin wax is used, which changes in volume by 1.15 times when it goes from solid to its molten state. Calling it a ‘waxtuator’, [BubsBuilds] characterized this expansion rate over the temperature range between solid and fully molten to make it a controllable actuator. In his experiments, a gap of less than 5 µm was maintained over twelve hours, showing how precise this device can be if you can control the temperature that the wax is kept at.

One major issue is the low conductivity of paraffin wax, which as some commentators remark can be solved by mixing something like fine copper particles into the wax to increase the thermal conductivity. In the shown implementation instead multiple channels in the aluminium block are used, which are melted by a TEC element.

The wax exerts pressure on a working fluid, which then pushes on a hydraulic cylinder that can be used for whatever precise linear actuating task has to be performed. Although initially water was used as a working fluid, this posed many issues with wax-water interface compatibility and vacuum degassing.

Although ethylene glycol makes for a better working fluid, this proved to be its own hassle. With the water-wax version a displacement sensor was thus used to measure and calibrate the whole setup. The electronics used to control the TEC in combination with the current temperature and displacement are a story in itself, but essential for making this device work.

While not something we often see tackled in the DIY space, we’ve covered a few teardowns of commercial units over the years.

Continue reading “Making A Wax Motor For Micrometer-Level Control” →

From Germanium To Diamond: The Many Shapes Of Semiconductors

November 4, 2026 by Maya Posch 4 Comments

It seems fair to say that semiconductor technology has been one of the most influential inventions in human history. Practically overnight it turned human technology from being large, cumbersome and power-hungry into an increasingly sleeker, more power-efficient and much more capable form. It has become practically impossible at this point to imagine modern society without semiconductor technology.

That said, we didn’t always use today’s silicon-based semiconductor technology, and although silicon-based semiconductors are exceedingly versatile and adaptable, they do have their limitations. The past years we have seen for example gallium-nitride semiconductors make big inroads in power switching technology, and more exotic forms like diamond-based semiconductors keep making their tantalizing appearances.

In this article we’ll take a look at how we ended up at silicon as the default for semiconductor technology, as well as why we may want to consider moving to other materials.

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Detecting An Eight Magnetic Pole State Using Chiral Phonons

November 3, 2026 by Maya Posch 5 Comments

The idea that magnetism doesn’t necessarily always have a dipolar configuration is not a new one, but it’s not an easy theory to find evidence for. Most recently a team of scientists at the University of Toronto used a new method involving vibrational energy in the form of phonons to find evidence for an octupolar magnetic order.

In the associated paper in Physical Review Letters (paywalled, arXiv version) by [Ruairidh Sutcliffe] et al. we can find more details on this method and what their findings may mean for various fields. Naturally, this is a quantum-level phenomenon that requires Raman spectroscopy to be detectable via said phonons.

The materials investigated here are also somewhat exotic, ranging from actinides like NpO₂ to transition metal oxides like Sr₂MgReO₆, while having on common strong spin-orbit coupling. Where the phonons come into play is that they can be used to indirectly measure crystal lattice distortions due to the pseudo-angular momentum assigned to the phonons. This generates pseudo-chiral phonons which then show up in the Raman spectroscopy.

Although finding evidence for octopolar magnetic order is interesting in itself, this way to measuring a crystal lattice’s structure makes for another fascinating research tool that can be used to study many similar phenomenon.

These quantum-level magnetic states could conceivably be used for anything from sensors to magnetic data storage, though any such research is unlikely to be commercialized any time soon.

The Components For Life May Not Have Arrived By Comet

November 3, 2026 by Maya Posch 14 Comments

When it comes to abiogenesis, i.e. the formation of the first biological cells on Earth, there are many theories on how this got kickstarted. One of the more popular theories involves the primordial Earth being seeded with the organic building blocks by comets hurtling through the atmosphere. Although organic compounds have been discovered on such comets, the question of whether these compounds could survive hurtling through Earth’s atmosphere and the rapid deceleration upon impact remained unanswered.

Hydrothermal vent in the Atlantic Ocean. (Source: NOAA)

Now a study by [Richard J. Anslow] et al. in Scientific Reports posits that the answer here is a very probable ‘no’. Using detailed cometary impact simulations and our current understanding of the formation and presence of these volatile organic molecules on comets it was found that the possibility of such molecules surviving the impact was extremely low.

The focus here was on hydrogen cyanide (HCN), with simulations showing a negligible amount of it surviving to make it onto Earth’s surface. Naturally from there other influences like hydrolysis will further dilute and degrade such molecules, making their effect on any biological activity highly unlikely. Meanwhile this comet-based delivery method was much more effective on a historical Mars – one capable of retaining liquid water – with more than five times successful deliveries of HCN.

Realistically, the much more likely source of such ingredients and the energy for the formation of the first biological cells on Earth would have been found near hydrothermal vents, which even today provide a rich mixture of chemicals that sustains entire ecosystems that are quite unlike those found here on the surface. For smaller planets like Mars the cometary route could however been a viable method for biological activity, which provides exciting prospects for similar bodies like Europa once we start exploring its oceans.

Turning Syngas Into Hydrocarbons With The Right Alpha

November 1, 2026 by Maya Posch 12 Comments

Although the Fischer-Tropsch synthesis (F-T synthesis) process is well-known and on face value quite straightforward, using it for DIY production of a somewhat defined length hydrocarbons is fairly tricky. This is the topic of a recent video by [Hyperspace Pirate], in which he goes over getting the right alpha value for his FT reactor in order to not just create the equivalent of crude oil.

This alpha value is determined by the temperature and pressure inside the reactor as the syngas – consisting of carbon monoxide and hydrogen – is encouraged by the catalyst material to turn into proper carbohydrates. At very low alpha values this process will finish very quickly, creating mostly methane (CH₄), while a higher number creates increasingly longer carbohydrate chains before they terminate with their final hydrogen molecules.

Since this process is exothermic, this creates many exciting opportunities for a production batch to be ruined unless you can somewhat control the temperature and pressure inside the reactor vessel. In the video a heater is used to kickstart the reaction, before it is turned off. As a catalyst an iron-based material is created that is packed inside the steel tube which forms the reactor vessel.

Through this the syngas is led, with the initial experiments producing a few mL of what appears to be pentane and hexane, with the rest apparently being gaseous methane, ethane and similar. This points to a fairly low alpha value, which is not ideal if your goal is to synthesize a specific hydrocarbon. With how complex this process is, there’s a good argument to be made that using F-T synthesis at a high alpha to churn out crude for standard distillation might be the easier method.

Continue reading “Turning Syngas Into Hydrocarbons With The Right Alpha” →

A clear plastic block is shown on a workbench. The plastic block has channels running through it, with liquid flowing through the channels. A pressure gauge is mounted to the top of the block, and an alcohol burner is placed near the base.

3D Printed Einstein-Szilard Refrigerator Cools With Fire

October 31, 2026 by Aaron Beckendorf 16 Comments

They may not deliver the highest efficiency, but absorption refrigerators have earned a persistent place in camper vans and industrial plants thanks to a few distinct advantages: they can operate using waste heat alone as an energy source, and they can be quite reliable due to their lack of moving parts. It can be a bit hard to understand their working principles, though, which is why [Ben Krasnow] built a transparent Einstein-Szilard refrigerator.

Most absorption refrigerators use ammonia and water as their working fluids; since the ammonia gas needs to condense at room temperature, the refrigerator requires pressures above what can be comfortably held in a glass or plastic enclosure. The Einstein-Szilard design, by contrast, uses a third liquid as its refrigerant. A strong solution of ammonia in water is separated by boiling, and the ammonia gas induces the refrigerant to evaporate by decreasing its partial pressure. The refrigerant and ammonia gasses then mix with water, in which the ammonia dissolves, leaving the refrigerant vapor to condense and start the cycle again. The newly reformed water-ammonia solution flows back into the boiler.

The refrigerant is usually butane, but since [Ben] was powering this pressurized system with an open flame, he opted instead for nonflammable perfluoropentane. The refrigerator body itself was 3D printed in clear resin, with a copper block transferring heat from the flame to the boiler chamber; ammonia solutions do dissolve copper, so this isn’t a long-term solution, but it works for a demonstration. The single internal path of the refrigerator presented some difficulties: since almost no pressure builds up between different parts of the system, a bubble in the wrong place can easily airlock it. In the end, [Ben] managed to get it working well enough to reach five degrees Celsius below the ambient temperature. Conveniently, he notes that, for alcohol at a sufficiently high concentration, you could cool your drink by burning a portion of it.

Ammonia-based refrigerators are a tough build for most hackers, but we have seen a salt-water-based absorption refrigerator before. For more less-known refrigerators, check out our article on strange cooling methods.

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Battery Prototype Uses Superextensive Quantum Effects To Charge Faster

October 28, 2026 by Maya Posch 18 Comments

Although the term ‘quantum battery’ is a bit of a vague term, the cell that [Kieran Hymas] et al. demonstrate in a recent paper does seem to suggest that it uses quantum effects to charge faster than would otherwise be possible, with this rate increasing faster than its volume, meaning at a superextensive rate.

The general idea behind a quantum battery is that these somehow use a quantum effect to store and release energy faster than would be possible using classical physics. First proposed in 2013, the initial Dicke model saw its theoretical quantum advantage shot down by 2020, leading to the search for alternative models.

We have previously seen claims of a quantum advantage in batteries based on the Sachdev-Ye-Kitaev model, such as by [Davide Rossini] et al., but this new paper may be the first prototype cell demonstrating a reproducible effect.

In the here demonstrated cell a microcavity is created with strong light-matter coupling, allowing for both energy storage and discharging, with the illuminated particles super-absorbing the light with what the researchers claim to be due to these particles cooperating using a quantum mechanism. Effectively scaling up the cell would thus scale up the charge- and discharge rate faster than in a conventional chemical cell.

Whether this demonstration can be replicated and expanded upon remains to be seen, naturally. The stored energy in this experiment was very small and the storage time only very brief, so for now it serves primarily as an interesting experimental result for researchers to dig through.