Science

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Everything You Ever Wanted To Know About The Manhattan Project (But Were Afraid To Ask)

September 12, 2025 by 2 Comments

There have been plenty of books and movies about how the Manhattan Project brought together scientists and engineers to create the nuclear bomb. Most of them don’t have a lot of technical substance, though. You know — military finds genius, genius recruits other geniuses, bomb! But if you want to hear the story of the engineering, [Brian Potter] tells it all. We mean, like, all of it.

If you’re looking for a quick three-minute read, you’ll want to give this a pass. Save it for a rainy afternoon when you can settle in. Even then, he skips past a lot of what is well known. Instead, he spends quite a bit of time discussing how the project addressed the technical challenges, like separating out U235.

Four methods were considered for that task. Creating sufficient amounts of plutonium was also a problem. Producing a pound of plutonium took 4,000 pounds of uranium. When you had enough material, there was the added problem of getting it together fast enough to explode instead of just having a radioactive fizzle.

There are some fascinating tidbits in the write-up. For example, building what would become the Oak Ridge facility required conductors for electromagnets. Copper, however, was in short supply. It was wartime, after all. So the program borrowed another good conductor, silver, from the Treasury Department. Presumably, they eventually returned it, but [Brian] doesn’t say.

There’s the old story that they weren’t entirely sure they wouldn’t ignite the entire atmosphere but, of course, they didn’t.  Not that the nuclear program didn’t have its share of bad luck.

Ore Formation Processes, Part Two: Hydrothermal Boogaloo

September 8, 2025 by 2 Comments

There’s a saying in mine country, the kind that sometimes shows up on bumper stickers: “If it can’t be grown, it has to be mined.” Before mining can ever start, though, there has to be ore in the ground. In the last edition of this series, we learned what counts as ore (anything that can be economically mined) and talked about the ways magma can form ore bodies. The so-called magmatic processes are responsible for only a minority of the mines working today. Much more important, from an economic point of view, are the so-called “hydrothermal” processes.

Come back in a few million years, and Yellowstone will be a great mining province.
Image: “Gyser Yellowstone” by amanderson2, CC BY 2.0

When you hear the word “hydrothermal” you probably think of hot water; in the context of geology, that might conjure images of Yellowstone and regions like it : Old Faithful geysers and steaming hot springs. Those hot springs might have a role to play in certain processes, but most of the time when a geologist talks about a “hydrothermal fluid” it’s a lot hotter than that.

Is there a point on the phase diagram that we stop calling it water? We’re edging into supercritical fluid territory, here. The fluids in question can be hundreds of degrees centigrade, and can carry things like silica (SiO2) and a metal more famous for not dissolving: gold. Perhaps that’s why we prefer to talk about a “fluid” instead of “water”. It certainly would not behave like water on surface; on the surface it would be superheated steam. Pressure is a wonderful thing.

Let’s return to where we left off last time, into a magma chamber deep underground. Magma isn’t just molten rock– it also contains small amounts of dissolved gasses, like CO2 and H2O. If magma cools quickly, the water gets trapped inside the matrix of the new rock, or even inside the crystal structure of certain minerals. If it cools slowly, however? You can get a hydrothermal fluid within the magma chamber.

Continue reading “Ore Formation Processes, Part Two: Hydrothermal Boogaloo” →

A laboratory benchtop is shown. To the left, there is a distillation column above a collecting flask, with a tube leading from the flask to an adapter. The adapter has a frame holding a glass tube with a teflon stopper at one end, into which a smaller glass tube leads. At the other end of the larger tube is a round flask suspended in an oil bath.

Building A Rotary Evaporator For The Home Lab

September 8, 2025 by 6 Comments

The rotary evaporator (rotovap) rarely appears outside of well-provisioned chemistry labs. That means that despite being a fundamentally simple device, their cost generally puts them out of reach for amateur chemists. Nevertheless, they make it much more convenient to remove a solvent from a solution, so [Markus Bindhammer] designed and built his own.

Rotary evaporators have two flasks, one containing the solution to be evaporated, and one that collects the condensed solvent vapors. A rotary joint holds the evaporating flask partially immersed in a heated oil bath and connects the flask’s neck to a fixed vapor duct. Solvent vapors leave the first flask, travel through the duct, condense in a condenser, and collect in the second flask. A motor rotates the first flask, which spreads a thin layer of the solution across the flask walls, increasing the surface area and causing the liquid to evaporate more quickly.

Possibly the trickiest part of the apparatus is the rotary joint, which in [Markus]’s implementation is made of a ground-glass joint adapter surrounded by a 3D-printed gear adapter and two ball bearings. A Teflon stopper fits into one end of the adapter, the evaporation flask clips onto the other end, and a glass tube runs through the stopper. The ball bearings allow the adapter to rotate within a frame, the gear enables a motor to drive it, the Teflon stopper serves as a lubricated seal, and the non-rotating glass tube directs the solvent vapors into the condenser.

The flasks, condenser, and adapters were relatively inexpensive commercial glassware, and the frame that held them in place was primarily made of aluminium extrusion, with a few other pieces of miscellaneous hardware. In [Markus]’s test, the rotovap had no trouble evaporating isopropyl alcohol from one flask to the other.

This isn’t [Markus]’s first time turning a complex piece of scientific equipment into an amateur-accessible project, or, for that matter, making simpler equipment. He’s also taken on several major industrial chemistry processes.

Heart Rate Monitoring Via WiFi

September 5, 2025 by 22 Comments

Before you decide to click away, thinking we’re talking about some heart rate monitor that connects to a display using WiFi, wait! Pulse-Fi is a system that monitors heart rate using the WiFi signal itself as a measuring device. No sensor, no wires, and it works on people up to ten feet away.

Researchers at UC Santa Cruz, including a visiting high school student researcher, put together a proof of concept. Apparently, your heart rate can modify WiFi channel state information. By measuring actual heart rate and the variations in the WiFi signal, the team was able to fit data to allow for accurate heart rate prediction.

The primary device used was an ESP32, although the more expensive Raspberry Pi performed the same trick using data generated in Brazil. The Pi appeared to work better, but it is also more expensive. However, that implies that different WiFi chipsets probably need unique training, which, we suppose, makes sense.

Like you, we’ve got a lot of questions about this one — including how repeatable this is in a real-world environment. But it does make you wonder what we could use WiFi permutations to detect. Or other ubiquitous RF signals like Bluetooth.

No need for a clunky wristband. If you could sense enough things like this, maybe you could come up with a wireless polygraph.

A worker inspects JUNO's acrylic sphere under the watching eye of PMTs

Worlds Largest Neutrino Detector Is Collecting Data In China

September 1, 2025 by 16 Comments

To say that neutrinos aren’t the easiest particles to study would be a bit of an understatement. Outside of dark matter, there’s not much in particle physics that is as slippery as the elusive “ghost particles” that are endlessly streaming through you and everything you own. That’s why its exciting news that JUNO is now taking data as the world’s largest detector.

First, in case you’re not a physics geek, let’s go back to basics. Neutrinos are neutral particles (the name was coined by Fermi as “little neutral one”) with very, very little mass and a propensity for slipping in between the more-common particles that make up everyday matter. The fact that neutrinos have mass is kind of weird, in that it’s not part of the Standard Model of Particle Physics. Since the Standard Model gets just about everything else right (except for dark matter) down to quite a few decimal points, well… that’s a very interesting kind of weird, hence the worldwide race to unravel the mysteries of the so-called “ghost particle”. We have an explainer article here for anyone who wants more background.

Continue reading “Worlds Largest Neutrino Detector Is Collecting Data In China” →

A 3D-printed case encloses a number of electronic components. In the top left of the case, a laser diode is mounted. In the top right, the laser beam is shining into a cuvette, which is glowing red from scattered light. In the bottom right, a small breadboard has an integrated circuit and a few parts mounted. In the bottom left is a large red circuit board marked “Rich UNO R3.”

Measuring Nanoparticles By Scattering A Laser

August 30, 2025 by 6 Comments

A fundamental difficulty of working with nanoparticles is that your objects of study are too small for an optical microscope to resolve, and thus measuring their size can be quite a challenge. Of course, if you have a scanning electron microscope, measuring particle size is straightforward. But for less well-equipped labs, a dynamic light scattering system, such as [Etienne]’s OpenDLS, fits the bill.

Dynamic light scattering works by shining a laser beam into a suspension of fine particles, then using a light sensor to measure the intensity of light scattered onto a certain point. As the particles undergo Brownian motion, the intensity of the scattered light changes. Based on the speed with which the scattered light varies, it’s possible to calculate the speed of the moving particles, and thus their size.

The OpenDLS uses a 3D printed and laser-cut frame to hold a small laser diode, which shines into a cuvette, on the side of which is the light sensor. [Etienne] tried a few different options, including a photoresistor and a light sensor designed for Arduino, but eventually chose a photodiode with a two-stage transimpedance amplifier. An Arduino samples the data at 67 kHz, then sends it over serial to a host computer, which uses SciPy and NumPy to analyse the data. Unfortunately, we were about six years late in getting to this story, and the Python program is a bit out of date by now (it was written in Python 2). It shouldn’t, however, be too hard for a motivated hacker to update.

With a standard 188 nm polystyrene dispersion, the OpenDLS calculated a size of 167 nm. Such underestimation seemed to be a persistent issue, probably caused by light being scattered multiple times. More dilution of the suspension would help, but it would also make the signal harder to measure, and the system’s already running near the limits of the hardware.

This isn’t the only creative way to measure the size of small particles, nor even the only way to investigate small particles optically. Of course, if you do have an electron microscope, nanoparticles make a good test target.

An image of a pigeon on the left and a breakdown of six of the different kind of feathers on the bird. The bird's right wing is white with black dots and has an arrow pointing to it saying, "Developing wing with feather buds." The left wing is grey with one feather highlighted in pink with the text "Adult wing with feathers" at the end of an arrow pointing to it. The six feather types on the right side of the image are flight feathers, illustrated in pink with the text "enable flight, support aerodynamic loads, morph depending on flying style, building blocks for wing planaform." In green, we have tail feathers and the text "Maneuverability and controlability." In blue are the contour feathers, accompanied by the text, "streamline, camouflage, and sexual display. Found above filoplumes and semiplumes." A black floofy branched structure shows us the downy feathers next to the text "thermal insulation." Filoplumes and semiplumes look to be both thin and bushy feathers in black with the text "Sense underlying feathers, found above downy feathers." Finally, we have a black, stick-like bristle feather with the text "Protect face and eyes, sense surroundings."

Feathers Are Fantastic, But Flummoxing For Engineers

August 29, 2025 by 7 Comments

Birds are pretty amazing creatures, and one of the most amazing things about them and their non-avian predecessors are feathers. Engineers and scientists are finding inspiration from them in surprising ways.

The light weight and high strength of feathers has inspired those who look to soar the skies, dating back at least as far as Ancient Greece, but the multifunctional nature of these marvels has led to advancements in photonics, thermal regulation, and acoustics. The water repellency of feathers has also led to interesting new applications in both food safety and water desalination beyond the obvious water repellent clothing.

Sebastian Hendrickx-Rodriguez, the lead researcher on a new paper about the structure of bird feathers states, “Our first instinct as engineers is often to change the material chemistry,” but feathers are made in thousands of varieties to achieve different advantageous outcomes from a single material, keratin. Being biological in nature also means feathers have a degree of self repair that human-made materials can only dream of. For now, some researchers are building biohybrid devices with real bird feathers, but as we continue our march toward manufacturing at smaller and smaller scales, perhaps our robots will sprout wings of their own. Evolution has a several billion year head start, so we may need to be a little patient with researchers.

Some birds really don’t appreciate Big Brother any more than we do. If you’re looking for some feathery inspiration for your next flying machine, how about covert feathers. And we’d be remiss not to look back at the Take Flight With Feather Contest that focused on the Adafruit board with the same name.