Static electricity often just seems like an everyday annoyance when a wool sweater crackles as you pull it off, or when a doorknob delivers an unexpected zap. Regardless, the phenomenon is much more fascinating and complex than these simple examples suggest. In fact, static electricity is direct observable evidence of the actions of subatomic particles and the charges they carry.

While zaps from a fuzzy carpet or playground slide are funny, humanity has learned how to harness this naturally occurring force in far more deliberate and intriguing ways. In this article, we’ll dive into some of the most iconic machines that generate static electricity and explore how they work.

What Is It?

Before we look at the fancy science gear, we should actually define what we’re talking about here. In simple terms, static electricity is the result of an imbalance of electric charges within or on the surface of a material. While positively-charged protons tend to stay put, electrons, with their negative charges, can move between materials when they come into contact or rub against one another. When one material gains electrons and becomes negatively charged, and another loses electrons and becomes positively charged, a static electric field is created. The most visible result of this is when those charges are released—often in the form of a sudden spark.

Since it forms so easily on common materials, humans have been aware of static electricity for quite some time. One of the earliest recorded studies of the phenomenon came from the ancient Greeks. Around 1000 BC, they noticed that rubbing amber with fur would then allow it to attract small objects like feathers. Little came of this discovery, which was ascribed as a curious property of amber itself. Fast forward to the 17th century, though, and scientists were creating the first machines designed to intentionally store or generate static electricity. These devices helped shape our understanding of electricity and paved the way for the advanced electrical technologies we use today. Let’s explore a few key examples of these machines, each of which demonstrates a different approach to building and manipulating static charge.

The Leyden Jar

Though not exactly a machine for generating static electricity, the Leyden jar is a critical part of early electrostatic experiments. Effectively a static electricity storage device, it was independently discovered twice, first by a German named Ewald Georg von Kleist in 1745. However, it gained its common name when it was discovered by Pieter van Musschenbroek, a Dutch physicist, sometime between 1745 and 1746. The earliest versions were very simple, consisting of water in a glass jar that was charged with static electricity conducted to it via a metal rod. The experimenter’s hand holding the jar served as one plate of what was a rudimentary capacitor, the water being the other. The Leyden jar thus stored static electricity in the water and the experimenter’s hand.

Eventually the common design became a glass jar with layers of metal foil both inside and outside, separated by the glass. Early experimenters would charge the jar using electrostatic generators, and then discharge it with a dramatic spark.

The Leyden jar is one of the first devices that allowed humans to store and release static electricity on command. It demonstrated that static charge could be accumulated and held for later use, which was a critical step in understanding the principles that would lead to modern capacitors. The Leyden jar can still be used in demonstrations of electrostatic phenomena and continues to serve as a fascinating link to the history of electrical science.

The Van de Graaff Generator

Perhaps the most iconic machine associated with generating static electricity is the Van de Graaff generator. Developed in the 1920s by American physicist Robert J. Van de Graaff, this machine became a staple of science classrooms and physics demonstrations worldwide. The device is instantly recognizable thanks to its large, polished metal sphere that often causes hair to stand on end when a person touches it.

The Van de Graaff generator works by transferring electrons through mechanical movement. It uses a motor-driven belt made of insulating material, like rubber or nylon, which runs between two rollers. At the bottom roller, plastic in this example, a comb or brush (called the lower electrode) is placed very close to the belt. As the belt moves, electrons are transferred from the lower roller onto the belt due to friction in what is known as the triboelectric effect. This leaves the lower roller positively charged and the belt carrying excess electrons, giving it a negative charge. The electric field surrounding the positively charged roller tends to ionize the surrounding air and attracts more negative charges from the lower electrode.

As the belt moves upward, it carries these electrons to the top of the generator, where another comb or brush (the upper electrode) is positioned near the large metal sphere. The upper roller is usually metal in these cases, which stays neutral rather than becoming intensely charged like the bottom roller. The upper electrode pulls the electrons off the belt, and they are transferred to the surface of the metal sphere. Because the metal sphere is insulated and not connected to anything that can allow the electrons to escape, the negative charge on the sphere keeps building up to very high voltages, often in the range of hundreds of thousands of volts. Alternatively, the whole thing can be reversed in polarity by changing the belt or roller materials, or by using a high voltage power supply to charge the belt instead of the triboelectric effect.

The result is a machine capable of producing massive static charges and dramatic sparks. In addition to its use as a demonstration tool, Van de Graaff generators have applications in particle physics. Since they can generate incredibly high voltages, they were once used to accelerate particles to high speeds for physics experiments. These days, though, our particle accelerators are altogether more complex. 

The Whimsical Wimshurst Machine

Another fascinating machine for generating static electricity is the Wimshurst machine, invented in the late 19th century by British engineer James Wimshurst. While less famous than the Van de Graaff generator, the Wimshurst machine is equally impressive in its operation and design.

The key functional parts of the machine are the two large, circular disks made of insulating material—originally glass, but plastic works too. These disks are mounted on a shared axle, but they rotate in opposite directions when the hand crank is turned. The surfaces of the disks have small metal sectors—typically aluminum or brass—which play a key role in generating static charge. As the disks rotate, brushes made of fine metal wire or other conductive material lightly touch their surfaces near the outer edges. These brushes don’t generate the initial charge but help to collect and amplify it once it is present.

The key to the Wimshurst machine’s operation lies in a process called electrostatic induction, which is essentially the influence that a charged object can exert on nearby objects, even without touching them. At any given moment, one small area of the rotating disk may randomly pick up a small amount of charge from the surrounding air or by friction. This tiny initial charge is enough to start the process. As this charged area on the disk moves past the metal brushes, it induces an opposite charge in the metal sectors on the other disk, which is rotating in the opposite direction.

For example, if a positively charged area on one disk passes by a brush, it will induce a negative charge on the metal sectors of the opposite disk at the same position. These newly induced charges are then collected by a pair of metal combs located above and below the disks. The combs are typically connected to Leyden jars to store the charge, until the voltage builds up high enough to jump a spark over a gap between two terminals.

The Wimshurst machine doesn’t create static electricity out of nothing; rather, it amplifies small random charges through the process of electrostatic induction as the disks rotate. As the charge is collected by brushes and combs, it builds up on the machine’s terminals, resulting in a high-voltage output that can produce dramatic sparks. This self-amplifying loop is what makes the Wimshurst machine so effective at generating static electricity.

The Wimshurst machine is seen largely as a curio today, but it did have genuine scientific applications back in the day. Beyond simply using it to investigate static electricity, its output could be discharged into Crookes tubes to create X-rays in a very rudimentary way.

The Electrophorus: Simple Yet Ingenious

One of the simplest machines for working with static electricity is the electrophorus, a device that dates back to 1762. Invented by Swedish scientist Johan Carl Wilcke, the electrophorus consists of two key parts: a flat dielectric plate and a metal disk with an insulating handle. The dielectric plate was originally made of resinous material, but plastic works too. Meanwhile, the metal disk is naturally conductive.

To generate static electricity with the electrophorus, the dielectric plate is first rubbed with a cloth to create a static charge through friction. This is another example of the triboelectric effect, as also used in the Van de Graaff generator. Once the plate is charged, the metal disk is placed on top of it. The disc then becomes charged by induction. It’s much the same principle as the Wimshurst machine, with the electrostatic field of the dielectric plate pushing around the charges in the metal plate until it too has a distinct charge.

For example, if the dielectric plate has been given a negative charge by rubbing, it will repel negative charges in the metal plate to the opposite side, giving the near surface a positive charge, and the opposite surface a negative charge. The net charge, though, remains neutral. But, if the metal disk is then grounded—for example, by briefly touching it with a finger—the negative charge on the disk can drained away, leaving it positively charged as a whole. This process does not deplete the charge on the dielectric, so it can be used to charge the metal disk multiple times, though the dielectric’s charge will slowly leak away in time.

Though it’s simple in design, the electrophorus remains a remarkable demonstration of static electricity generation and was widely used in early electrostatic experiments. A particularly well-known example is that of Georg Lichtenberg. He used a version a full two meters in diameter to create large discharges for his famous Lichtenberg figures. Overall, it’s an excellent tool for teaching the basic principles of electrostatics and charge separation—particularly given how simple it is in construction compared to some of the above machines.

Zap

Static electricity, once a mysterious and elusive force, has long since been tamed and turned into a valuable tool for scientific inquiry and education. Humans have developed numerous machines to generate, manipulate, and study static electricity—these are just some of the stars of the field. Each of these devices played an important role in furthering humanity’s understanding of electrostatics, and to a degree, physics in general.

Today, these machines continue to serve as educational tools and historical curiosities, offering a glimpse into the early days of electrical science—and they still spark fascination on the regular, quite literally. Static electricity may be an everyday phenomenon, but the machines that harness its power are still captivating today. Just go to any local science museum for the proof!

 

[Project 326] wanted to know exactly what gas was in some glass tubes. The answer, of course, is to use a spectrometer, but that’s an expensive piece of gear, right? Not really. Sure, these cheap devices aren’t perfect, but they are serviceable and, as the video below shows, there are ways to work around some of the limitations.

The two units in question are “The Little Garden” spectrometer and a TLM-2. Neither are especially sensitive, but both are well under $100, so you can’t expect much. Because the spectrometers were not very sensitive, a 3D printed jig and lens were used to collect more light and block ambient light interference. The jigs also allowed the inclusion of special filters, which enhanced performance quite a bit. The neon bulbs give off the greatest glow when exposed to high voltage. Other bulbs contain things like helium, xenon, and carbon dioxide. There were also tubes with mercury vapor and even deuterium.

We’ll admit it. Not everyone needs a spectrometer, but if you do, there’s a lot of really interesting info on how to get the most out of these cheap devices. Apparently, [Project 326] was frustrated that he couldn’t buy an X-ray spectrometer and has vowed to create one, so we’ll be interested to see how that goes.

Some homebrew spectrometers can get pretty fancy. Of course, there’s more to spectroscopy than just optics.

Although not as prevalent as Flash memory storage, ferroelectric RAM (FeRAM) offers a range of benefits over the former, mostly in terms of endurance and durability, which makes it popular for a range of (niche) applications. Recently [Ken Shirriff] had a look inside a Ramtron FM24C64 FeRAM IC from 1999, to get an idea of how it works. The full die photo can be seen above, and it can store a total of 64 kilobit.

One way to think of FeRAM is as a very small version of magnetic core memory, with lead-zirconate-titanate (PZT) ferroelectric elements making up the individual bits. These PZT elements are used as ferroelectric capacitors, i.e. the ferroelectric material is the dielectric between the two plates, with a positive voltage storing a ‘1’, and vice-versa.

In this particular FeRAM chip, there are two capacitors per bit, which makes it easier to distinguish the polarization state and thus the stored value. Since the distinction between a 0 and a 1 is relatively minor, the sense amplifiers are required to boost the signal. After a read action, the stored value will have been destroyed, necessitating a write-after-read action to restore the value, all of which adds to the required logic to manage the FeRAM. Together with the complexity of integrating these PZT elements into the circuitry this makes these chips relatively hard to produce and scale down.

You can purchase FeRAM off-the-shelf and research is ongoing, but it looks to remain a cool niche technology barring any kind of major breakthrough. That said, the Sega Sonic the Hedgehog 3 cartridges which used an FeRAM chip for save data are probably quite indestructible due to this technology.

Everyone knows that time’s arrow only goes in one direction, regardless of the system or material involved. In the case of material time, i.e. the ageing of materials such as amorphous materials resulting from glass transition, this material time is determined after the initial solidification by the relaxation of localized stresses and medium-scale reordering. These changes are induced by the out-of-equilibrium state of the amorphous material, and result in changes to the material’s properties, such as a change from ductile to a brittle state in metallic glasses. It is this material time which the authors of a recent paper (preprint) in Nature Physics postulates to be reversible.

Whether or not this is possible is said to be dependent on the stationarity of the stochastic processes involved in the physical ageing. Determining this stationarity through the investigation of the material time in a number of metallic glass materials (1-phenyl-1-propanol, laponite and polymerizing epoxy) was the goal of this investigation by [Till Böhmer] and colleagues, and found that at least in these three materials to be the case, suggesting that this process is in fact reversible.

Naturally, the primary use of this research is to validate theories regarding the ageing of materials, other aspects of which have been investigated over the years, such as the atomic dynamics by [V.M Giordano] and colleagues in a 2016 paper in Nature Communications, and a 2022 study by [Birte Riechers] and colleagues in Science Advances on predicting the nonlinear physical ageing process of glasses.

While none of these studies will give us time-travel powers, it does give us a better understanding of how materials age over time, including biological systems like our bodies. This would definitely seem to be a cause worthy of our time.

Header image: Rosino on Flickr, CC BY-SA 2.0.

One of the hardest things about studying electricity, and by extension electronics, is that you generally can’t touch or see anything directly, and if you can you’re generally having a pretty bad day. For teaching something that’s almost always invisible, educators have come up with a number of analogies for helping students understand the inner workings of this mysterious phenomenon like the water analogy or mechanical analogs to electronic circuits. One of [Thomas]’s problems with most of these devices, though, is that they don’t have any amplification or “fan-out” capability like a real electronic circuit would. He’s solved that with a unique mechanical amplifier.

Digital logic circuits generally have input power and ground connections in addition to their logic connection points, so [Thomas]’s main breakthrough here is that the mechanical equivalent should as well. His uses a motor driving a shaft with a set of pulleys, each of which has a fixed string wrapped around the pulley. That string is attached to a second string which is controlled by an input. When the input is moved the string on the pulley moves as well but the pulley adds a considerable amount of power to to the output which can eventually be used to drive a much larger number of inputs. In electronics, the ability to drive a certain number of inputs from a single output is called “fan-out” and this device has an equivalent fan-out of around 10, meaning each output can drive ten inputs.

[Thomas] calls his invention capstan lever logic, presumably named after a type of winch used on sailing vessels. In this case, the capstan is the driven pulley system. The linked video shows him creating a number of equivalent circuits starting with an inverter and working his way up to a half adder and an RS flip-flop. While the amplifier pulley does take a minute to wrap one’s mind around, it really helps make the equivalent electronic circuit more intuitive. We’ve seen similar builds before as well which use pulleys to demonstrate electronic circuits, but in a slightly different manner than this build does.

Down here at the bottom of our ocean of air, it’s easy to get complacent about the hazards our universe presents. We feel safe from the dangers of the vacuum of space, where radiation sizzles and rocks whizz around. In the same way that a catfish doesn’t much care what’s going on above the surface of his pond, so too are we content that our atmosphere will deflect, absorb, or incinerate just about anything that space throws our way.

Or will it? We all know that there are things out there in the solar system that are more than capable of wiping us out, and every day holds a non-zero chance that we’ll take the same ride the dinosaurs took 65 million years ago. But if that’s not enough to get you going, now we have to worry about gamma-ray bursts, searing blasts of energy crossing half the universe to arrive here and dump unimaginable amounts of energy on us, enough to not only be measurable by sensitive instruments in space but also to effect systems here on the ground, and in some cases, to physically alter our atmosphere.

Gamma-ray bursts are equal parts fascinating physics and terrifying science fiction. Here’s a look at the science behind them and the engineering that goes into detecting and studying them.

Collapsars and Neutron Stars

Although we now know that gamma-ray bursts are relatively common, it wasn’t all that long ago that we were ignorant of their existence, thanks in part to our thick, protective atmosphere. The discovery of GRBs had to wait for the Space Race to couple with Cold War paranoia, which resulted in Project Vela, a series of early US Air Force satellites designed in part to watch for Soviet compliance with the Partial Test Ban Treaty, which forbade everything except underground nuclear tests. In 1967, gamma ray detectors on satellites Vela 3 and Vela 4 saw a flash of gamma radiation that didn’t match the signature of any known nuclear weapon. Analysis of the data from these and subsequent flashes revealed that they came from space, and the race to understand these energetic cosmic outbursts was on.

Gamma-ray bursts are the most energetic phenomena known, with energies that are almost unfathomable. Their extreme brightness, primarily as gamma rays but across the spectrum and including visible light, makes them some of the most distant objects ever observed. To put their energetic nature into perspective, a GRB in 2008, dubbed GRB 080319B, was bright enough in the visible part of the spectrum to just be visible to the naked eye even though it was 7.5 billion light years away. That’s more than halfway across the observable universe, 3,000 times farther away than the Andromeda galaxy, normally the farthest naked-eye visible object.

For all their energy, GRBs tend to be very short-lived. GRBs break down into two rough groups. Short GRBs last for less than about two seconds, with everything else falling into the long GRB category. About 70% of GRBs we see fall into the long category, but that might be due to the fact that the short bursts are harder to see. It could also be that the events that precipitate the long variety, hypernovae, or the collapse of extremely massive stars and the subsequent formation of rapidly spinning black holes, greatly outnumber the progenitor event for the short category of GRBs, which is the merging of binary neutron stars locked in a terminal death spiral.

The trouble is, the math doesn’t work out; neither of these mind-bogglingly energetic events could create a burst of gamma rays bright enough to be observed across half the universe. The light from such a collapse would spread out evenly in all directions, and the tyranny of the inverse square law would attenuate the signal into the background long before it reached us. Unless, of course, the gamma rays were somehow collimated. The current thinking is that a disk of rapidly spinning material called an accretion disk develops outside the hypernova or the neutron star merger. The magnetic field of this matter is tortured and twisted by its rapid rotation, with magnetic lines of flux getting tangled and torn until they break. This releases all the energy of the hypernova or neutron star merger in the form of gamma rays in two tightly focused jets aligned with the pole of rotation of the accretion disk. And if one of those two jets happens to be pointed our way, we’ll see the resulting GRB.

Crystals and Shadows

But how exactly do we detect gamma-ray bursts? The first trick is to get to space, or at least above the bulk of the atmosphere. Our atmosphere does a fantastic job shielding us from all forms of cosmic radiation, which is why the field of gamma-ray astronomy in general and the discovery of GRBs in particular had to wait until the 1960s. A substantial number of GRBs have been detected by gamma-ray detectors carried aloft on high-altitude balloons, especially in the early days, but most dedicated GRB observatories are now satellite-borne

Gamma-ray detection technology has advanced considerably since the days of Vela, but a lot of the tried and true technology is still used today. Scintillation detectors, for example, use crystals that release photons of visible light when gamma rays of a specific energy pass through them. The photons can then be amplified by photomultiplier tubes, resulting in a pulse of current proportional to the energy of the incident gamma ray. This is the technology used by the Gamma-ray Burst Monitor (GBM) aboard the Fermi Gamma-Ray Space Telescope, a satellite that was launched in 2008. Sensors with the GBT are mounted around the main chassis of Fermi, giving it a complete very of the sky. It consists of twelve sodium iodide detectors, each of which is directly coupled to a 12.7-cm diameter photomultiplier tube. Two additional sensors are made from cylindrical bismuth germanate scintillators, each of which is sandwiched between two photomultipliers. Together, the fourteen sensors cover from 8 keV to 30 MeV,  and used in concert they can tell where in the sky a gamma-ray burst has occurred.

Ionization methods are also used as gamma-ray detectors. The Niel Gehrels Swift Observatory, a dedicated GRB hunting satellite that was launched in 2004, has an instrument known as the Burst Alert Telescope, or BAT. This instrument has a very large field of view and is intended to monitor a huge swath of sky. It uses 32,768 cadmium-zinc-telluride (CZT) detector elements, each 4 x 4 x 2 mm, to directly detect the passage of gamma rays. CZT is a direct-bandgap semiconductor in which electron-hole pairs are formed across an electric field when hit by ionizing radiation, producing a current pulse. The CZT array sits behind a fan-shaped coded aperture, which has thousands of thin lead tiles arranged in an array that looks a little like a QR code. Gamma rays hit the coded aperture first, casting a pattern on the CZT array below. The pattern is used to reconstruct the original properties of the radiation beam mathematically, since conventional mirrors and lenses don’t work with gamma radiation. The BAT is used to rapidly detect the location of a GRB and to determine if it’s something worth looking at. If it is, it rapidly slews the spacecraft to look at the burst with its other instruments and instantly informs other gamma observatories about the source so they can take a look too.

The B.O.A.T.

On October 9, 2022, both Swift and Fermi, along with dozens of other spacecraft and even some ground observatories, would get to witness a cataclysmically powerful gamma-ray burst. Bloodlessly named GRB 221009A but later dubbed “The BOAT,” for “brightest of all time,” the initial GRB lasted for an incredible ten minutes with a signal that remained detectable for hours. Coming from the direction of the constellation Sagittarius from a distance of 2.4 billion light years, the burst was powerful enough to saturate Fermi’s sensors and was ten times more powerful than any signal yet received by Swift.

Almost everything about the BOAT is fascinating, and the superlatives are too many to list. The gamma-ray burst was so powerful that it showed up in the scientific data of spacecraft that aren’t even equipped with gamma-ray detectors, including orbiters at Mars and Voyager 1. Ground-based observatories noted the burst, too, with observatories in Russia and China noting very high-energy photons in the range of tens to hundreds of TeV arriving at their detectors.

The total energy released by GRB 221009A is hard to gauge with precision, mainly because it swamped the very instruments designed to measure it. Estimates range from 10⁴⁸ to 10⁵⁰ joules, either of which dwarfs the total output of the Sun over its entire 10 billion-year lifespan. So much energy was thrown in our direction in such a short timespan that even our own atmosphere was impacted. Lightning detectors in India and Germany were triggered by the burst, and the ionosphere suddenly started behaving as if a small solar flare had just occurred. Most surprising was that the ionospheric effects showed up on the daylight side of the Earth, swamping the usual dampening effect of the Sun.

When the dust had settled from the initial detection of GRB 221009A, the question remained: What happened to cause such an outburst? To answer that, the James Webb Space Telescope was tasked with peering into space, off in the direction of Sagittarius, where it found pretty much what was expected — the remains of a massive supernova. In fact, the supernova that spawned this GRB doesn’t appear to have been particularly special when compared to other supernovae from similarly massive stars, which leaves the question of how the BOAT got to be so powerful.

Does any of this mean that a gamma-ray burst is going to ablate our atmosphere and wipe us out next week? Probably not, and given that this recent outburst was estimated to be a one-in-10,000-year event, we’re probably good for a while. It seems likely that there’s plenty that we don’t yet understand about GRBs, and that the data from GRB 221009A will be pored over for decades to come. It could be that we just got lucky this time, both in that we were in the right place at the right time to see the BOAT, and that it didn’t incinerate us in the process. But given that on average we see one GRB per day somewhere in the sky, chances are good that we’ll have plenty of opportunities to study these remarkable events.

One of the exciting aspects of some fields of physics is that they involve calculating the expected time until the Universe ends or experiences fundamental shifts that would render most if not all of the ‘laws of physics’ invalid. Within the Standard Model (SM), the false vacuum state is one such aspect, as it implies that the Universe’s quantum fields that determine macrolevel effects like mass can shift through quantum field decay into a lower, more stable state. One such field is the Higgs field, which according to a team of researchers may decay sooner than we had previously assumed.

As the Higgs field (through the Higgs boson) is responsible for giving particles mass, it’s not hard to imagine the chaos that would ensue if part of the Higgs field were to decay and cause a spherical ripple effect throughout the Universe. Particle masses would change, along with all associated physics, as suddenly the lower Higgs field state means that everything has significantly more mass. To say that it would shake up the Universe would an understatement.

Of course, this expected time-to-decay has only shifted from 10⁷⁹⁴ years to 10⁷⁹⁰ years with the corrections to the  previous calculations as provided in the paper by [Pietro Baratella] and colleagues, and they also refer to it as ‘slightly shorter’. A sidenote here is also that the electroweak vacuum’s decay is part of the imperfect SM, which much like the false vacuum hypothesis are part of these models, and not based on clear empirical evidence (yet).

NASA’s ACS3 (Advanced Composite Solar Sail System) is currently fully deployed in low Earth orbit, and stargazers can spot it if they know what to look for. It’s actually one of the brightest things in the night sky. When the conditions are right, anyway.

What conditions are those? Orientation, mostly. ACS3 is currently tumbling across the sky while NASA takes measurements about how it acts and moves. Once that’s done, the spacecraft will be stabilized. For now, it means that visibility depends on the ACS’s orientation relative to someone on the ground. At it’s brightest, it appears as bright as Sirius, the brightest star in the night sky.

ACS3 is part of NASA’s analysis and testing of solar sail technology for use in future missions. Solar sails represent a way of using reflected photons (from sunlight, but also possibly from a giant laser) for propulsion.

This perhaps doesn’t have much in the way of raw energy compared to traditional thrusters, but offers low cost and high efficiency (not to mention considerably lower complexity and weight) compared to propellant-based solutions. That makes it very worth investigating. Solar sail technology aims to send a probe to Alpha Centauri within the next twenty years.

Want to try to spot ACS3 with your own eyes? There’s a NASA app that can alert you to sighting opportunities in your local time and region, and even guide you toward the right region of the sky to look. Check it out!

The Voynich Manuscript is a medieval codex written in an unknown alphabet and is replete with fantastic illustrations as unusual and bizarre as they are esoteric. It has captured interest for hundreds of years, and expert [Lisa Fagin Davis] shared interesting results from using multispectral imaging on some pages of this highly unusual document.

We should make it clear up front that the imaging results have not yielded a decryption key (nor a secret map or anything of the sort) but the detailed write-up and freely-downloadable imaging results are fascinating reading for anyone interested in either the manuscript itself, or just how exactly multispectral imaging is applied to rare documents. Modern imaging techniques might get leveraged into things like authenticating sealed packs of Pokémon cards, but that’s not all it can do.

Because multispectral imaging involves things outside our normal perception, the results require careful analysis rather than intuitive interpretation. Here is one example: multispectral imaging may yield faded text visible “between the lines” of other text and invite leaping to conclusions about hidden or erased content. But the faded text could be the result of show-through (content from the opposite side of the page is being picked up) or an offset (when a page picks up ink and pigment from its opposing page after being closed for centuries.)

[Lisa] provides a highly detailed analysis of specific pages, and explains the kind of historical context and evidence this approach yields. Make some time to give it a read if you’re at all interested, we promise it’s worth your while.

Although we generally assume that opacity is the normal look for animals like us humans, this factoid is only correct for as long as you maintain the dissimilar optical refraction indices of skin and the more aqueous underlying structures. What if you could change the refraction index of skin? If you could prevent the normal scattering at the interface, you could reveal the structures underneath, effectively rendering skin transparent. [Zihao Uo] and others demonstrate this in a paper published in Science.

The substance they used was the common food dye known as tartrazine, which also goes by the names of Yellow 5 and E102 when it is used in food (like Doritos), cosmetics, and drugs. By rubbing the tartrazine into the skin of mice, the researchers were able to observe underlying blood vessels and muscles. Simulations predicted that the dye would change the refraction index mismatch between lipids and water which normally causes the light scattering that creates the skin’s opaque appearance. With the dye rubbed into the skin, the effect worked to a depth of about 3 mm, which makes it useful for some research and possible medical applications, but not quite at the ‘jellyfish-transparency’ levels that some seem to have imagined at the news.

Researchers and medical personnel have long wished for this kind of in vivo tissue transparency. A 2019 review article by [Mikhail Inyushin] and colleagues in Molecules provides an overview of the many possible ways, both genetic and chemical, that you might see through skin. Tartrazine has a significant advantage: it is generally considered to be a harmless food dye. In addition, reversing the effect is as simple as washing the dye off.

Naturally, human skin will be trickier than that of mice due to the varying presence of melanin. So it will take more work to use this technique on people, but there are many mice and other common lab test critters who are breathing a deep sigh of relief as the scalpel can be put away for some types of studies.

For now, better to stick with MRI. And fair warning: there’s no need to rush out to rub Doritos on your PCB — it doesn’t work.

What happens when an unfortunate bug ends up in a spider’s web? It gets bitten and wrapped in silk, and becomes a meal. But if the web belongs to an orb-weaver and the bug is a male firefly, it seems the trapped firefly — once bitten — ends up imitating a female’s flash pattern and luring other males to their doom.

Fireflies communicate with flash patterns (something you can experiment with yourself using nothing more than a green LED) and males looking to mate will fly around flashing a multi-pulse pattern with their two light-emitting lanterns. Females will tend to remain in one place and flash single-pulse patterns on their one lantern.

When a male spots a female, they swoop in to mate. Spiders have somehow figured out a way to actively take advantage of this, not just inserting themselves into the process but actively and masterfully manipulating male fireflies, causing them to behave in a way they would normally never do. All with the purpose of subverting firefly behavior for their own benefit.

It all started with an observation that almost all fireflies in webs were male, and careful investigation revealed it’s not just some odd coincidence. When spiders are not present, the male fireflies don’t act any differently. When a spider is present and detects a male firefly, the spider wraps and bites the firefly differently than other insects. It’s unknown exactly what happens, but this somehow results in the male firefly imitating a female’s flash patterns. Males see this and swoop in to mate, but with a rather different outcome than expected.

The research paper contains added details but it’s clear that there is more going on in this process than meets the eye. Spiders are already fascinating creatures (we’ve seen an amazing eye-tracking experiment on jumping spiders) and it’s remarkable to see this sort of bio-hacking going on under our very noses.

Ever needed a strong yet adhesive-free way to really stick PLA to glass? Neither have we, but nevertheless there’s a way to use aluminum foil and an IR fiber laser to get a solid bond with a little laser welding between the dissimilar materials.

It turns out that aluminum can be joined to glass by using a pulsed laser process, and PLA can be joined to aluminum with a continuous wave laser process. Researchers put them together, and managed to reliably do both at once with a single industrial laser.

By putting a sacrificial sheet of thin aluminum foil between 3D printed PLA and glass, then sending the laser through the glass into the aluminum, researchers were able to bond it all together in an adhesive-free manner with precise control, and very little heat to dissipate. No surface treatment of any kind required. The bond is at least as strong as any adhesive-based solution, so there’s no compromising on strength.

When it comes to fabrication, having to apply and manage adhesives is one of the least-preferable options for sticking two things together, so there’s value in the idea of something like this.

Still, it’s certainly a niche application and we’ll likely stick to good old superglue, but we honestly didn’t know laser welding could bond aluminum to glass or to PLA, let along both at once like this.

Researchers at the University of British Columbia leveraged an unusual discovery into ultra-black material made from wood. The deep, dark black is not the result of any sort of dye or surface coating; it’s structural change to the wood itself that causes it to swallow up at least 99% of incoming light.

The discovery was partially accidental, as researchers happened upon it while looking at using high-energy plasma etching to machine the surface of wood in order to improve it’s water resistance. In the process of doing so, they discovered that with the right process applied to the right thickness and orientation of wood grain, the plasma treatment resulted in a surprisingly dark end result. Fresh from the plasma chamber, a wood sample has a thin coating of white powder that, once removed, reveals an ultra-black surface.

The resulting material has been dubbed Nxylon (the name comes from mashing together Nyx, the Greek goddess of darkness, with xylon the Greek word for wood) and has been prototyped into watch faces and jewelry. It’s made from natural materials, the treatment doesn’t create or involve nasty waste, and it’s an economical process. For more information, check out UBC’s press release.

You have probably heard about Vantablack (and how you can’t buy any) and artist Stuart Semple’s ongoing efforts at making ever-darker and accessible black paint. Blacker than black has applications in optical instruments and is a compelling thing in the art world. It’s also very unusual to see an ultra-black anything that isn’t the result of a pigment or surface coating.

Here’s a novel ratchet mechanism developed by researchers that demonstrates how a single object — in this case a gear shaped like a six-pointed star — can rectify the disordered energy of its environment into one-way motion.

The Feynman–Smoluchowski ratchet has alternating surface treatments on the sides of its points, accomplished by applying a thin film layer to create alternating smooth/rough faces. This difference in surface wettability is used to turn agitation of surrounding water into a ratcheting action, or one-way spin.

This kind of mechanism is known as an active Brownian ratchet, but unlike other designs, this one doesn’t depend on the gear having asymmetrical geometry. Instead of an asymmetry in shape, there’s an asymmetry in the gear tooth surface treatments. You may be familiar with the terms hydrophobic and hydrophilic, which come down to a difference in surface wettability. The gear’s teeth having one side of each is what rectifies the chaotic agitation of the surrounding water into a one-way spin. Scaled down far enough, these could conceivably act as energy-harvesting micromotors.

Want more detail? The published paper is here, and if you think you might want to play with this idea yourself there are a few different ways to modify the surface wettability of an object. High voltage discharge (for example from a Tesla coil) can alter surface wettability, and there are off-the-shelf hydrophobic coatings we’ve seen used in art. We’ve even seen an unusual clock that relied on the effect.

Neon lamps are fun to play with. These old-school indicators were once heavily utilized in many types of equipment for indication purposes but now seem largely relegated to mains voltage indication duties. Here’s a fun video by [Ashish Derhgaen], discussing the photoelectric effect of neon lamps with some simple demonstrations.

[Ashish] demonstrates the well-known photoelectric effect by triggering a sub-biased neon lamp with visible light from an LED. Neon bulbs work on the principle of voltage-induced ionization, creating a visible glowing plasma. If the applied voltage is high enough, around 60 to 80 V, electrons get knocked off the neutral neon atoms. The now free electrons, roaming around highly energized, will eventually come across a neon ion (missing an electron) and recombine to make it neutral again.

The results are a lower total energy state, and the difference in energy is resolved by the emission of a photon of light, which, in the case of neon, is a dull reddish-orange. Nothing unusual there. However, nothing will happen if the applied voltage bias is just below this device-specific threshold. There’s not enough energy to strip electrons.

Apply an external light source, and this threshold can be exceeded. The photons from the LED are just energetic enough to strip a small number of electrons from the surface of the electrodes, and this causes a cascade, or avalanche effect, lighting up the plasma and turning on the neon lamp. Take away the external light source, and it dies down and goes dark.

The video also shows an interesting effect due to the wavelength of applied light. The photon energy needed to release an electron depends on the atom it strikes. Neon bulbs have all manner of electrode materials. [Ashish] shows that a particular neon lamp can be excited to emit a specific wavelength corresponding to a certain energy level. With some materials science work, this can then be used to ascertain what the electrode material is. Finally, the video shows some simple astable and relaxation oscillators initiated by light, making us wonder if one neon bulb could activate some neighboring bulbs and create a neat wave propagation effect for some electrode material and bias levels? You can see in the video that when the spectrum thrown from the prism is passed over the bulb, it illuminates in the orange section. So this could work. If you know, then do let us know with some examples.

Neon light hacks are plentiful around here. Neon lamps have many other uses beyond indication, even detecting sound. Of course, they look nice, but driving them is a hassle. Why not just fake the look with modern tech?

The simple definition of a mean is that of a numeric quantity which represents the center of a collection of numbers. Here the trick lies in defining the exact type of numeric collection, as beyond the arithmetic mean (AM for short, the sum of all values divided by their number) there are many more, with the other two classical Pythagorean means being the geometric mean (GM) and harmonic mean (HM).

The question that many start off with, is what the GM and AM are and why you’d want to use them, which is why [W.D.] wrote a blog post on that topic that they figure should be somewhat intuitive relative to digging through search results, or consulting the Wikipedia entries.

Compared to the AM, the GM uses the product of the values rather than the sum, which makes it a good fit for e.g. changes in a percentage data set. One thing that [W.D] argues for is to use logarithms to grasp the GM, as this makes it more obvious and closer to taking the AM. Finally, the HM is useful for something like the average speed across multiple trips, and is perhaps the easiest to grasp.

Ultimately, the Pythagorean means and their non-Pythagorean brethren are useful for things like data analysis and statistics, where using the right mean can reveal interesting data, much like how other types using something like the median can make a lot more sense. The latter obviously mostly in the hazy field of statistics.

No matter what approach works for you to make these concepts ‘click’, they’re all very useful things to comprehend, as much of every day life revolves around them, including concepts like ‘mean time to failure’ for parts.

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Top image: Cycles of sunspots for the last 400 years as an example data set to apply statistical interpretations to. (Credit: Robert A. Rohde, CC BY-SA 3.0)

[The Thought Emporium] has been fascinated by holograms for a long time, and in all sorts of different ways. His ultimate goal right now is to work up to creating holograms using chocolate, but along the way he’s found another interesting way to manipulate light. Using specialized diffraction gratings, a laser, and a few lines of code, he explores a unique way of projecting hologram-like images on his path to the chocolate hologram.

There’s a lot of background that [The Thought Emporium] has to go through before explaining how this project actually works. Briefly, this is a type of “transmission hologram” that doesn’t use a physical object as a model. Instead, it uses diffraction gratings, which are materials which are shaped to light apart in specific ways. After some discussion he demonstrates creating diffraction gratings using film. Certain diffraction patterns, including blocking all of the light source, can actually be used as a lens as the light bends around the blockage into the center of the shadow where there can be focal points. From there, a special diffraction lens can be built.

The diffraction lens can be shaped into any pattern with a small amount of computer code to compute the diffraction pattern for a given image. Then it’s transferred to film and when a laser is pointed at it, the image appears on the projected surface. Diffraction gratings like these have a number of other uses as well; the video also shows a specific pattern being used to focus a telescope for astrophotography, and a few others in the past have used them to create the illusive holographic chocolate that [The Thought Emporium] is working towards.

There may not be many radio astronomy printouts that have achieved universal fame, but the one from Ohio State University’s Big Ear telescope upon which astronomer [Jerry R. Ehman] wrote “WOW!” is definitely one of them. It showed an intense one-off burst that defied attempts to find others like it, prompting those who want to believe to speculate that it might have been the product of an extraterrestrial civilization. Sadly for them the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo has provided an explanation by examining historical data from the Arecibo telescope.

The radio signal in question lay on the hydrogen line frequency at 1420 MHz, and by looking at weaker emissions from cold hydrogen clouds they suggest that the WOW! signal may have come from a very unusual stimulation of one of these clouds. A magnetar is a type of neutron star which can create an intense magnetic field, and their suggestion is that Big Ear was in the lucky position of being in the right place at the right time to see one of these through a hydrogen cloud. The field would excite the hydrogen atoms to maser-like emission of radiation, leading to the unexpected blip on that printout.

There’s a question as to whether speculation about aliens is helpful to the cause of science, but in answer to that we’d like to remind readers that we wouldn’t be talking about magnetars now without it, and that the WOW! signal was in fact part of an early SETI experiment. Better keep on searching then!

Meanwhile readers with long memories will recollect us looking at the WOW! signal before.

In theory, water and electric current will cause electrolysis and produce oxygen and hydrogen as the water breaks apart. In practice, doing it well can be tricky. [Relic] shows an efficient way to produce an electrolysis cell using a few plastic peanut butter jars and some hardware.

The only tricky point is that you need hardware made of steel and not zinc or other materials. Well, that and the fact that the gasses you produce are relatively dangerous.

To that end, [Relic] includes an “I don’t want to explode switch” in the system by routing tubes of gas through a second jar filled with water so that the water will block its return.

Of course, we’ve seen the same setup created with a battery, two coils of wire, and some test tubes, but this can certainly produce more hydrogen faster. Like most of these designs, you can scale them by adding more steel parts. The more surface area, the more gas you’ll produce.

We’ve seen a number of similar generators before, but each one is a little different. If you want to get really fancy, you can turn to automation.