DB Cooper Case Could Close Soon Thanks To Particle Evidence

January 23, 2024 by Kristina Panos 47 Comments

It’s one of the strangest unsolved cases, and even though the FBI closed their investigation back in 2016, this may be the year it cracks wide open. On November 24, 1971, Dan Cooper, who would become known as DB Cooper due to a mistake by the media, skyjacked a Boeing 727 — Northwest Orient Airlines Flight 305 — headed from Portland to Seattle.

During the flight, mild-mannered Cooper coolly notified a flight attendant sitting behind him via neatly-handwritten note that he had a bomb in his briefcase. His demands were a sum of $200,000 (about $1.5 M today) and four parachutes once they got to Seattle. Upon landing, Cooper released the passengers and demanded that the plane be refueled and pointed toward Mexico City with him and most of the original crew aboard. But around 30 minutes into the flight, Cooper opened the plane’s aft staircase and vanished, parachuting into the night sky.

In the investigation that followed, the FBI recovered Cooper’s clip-on tie, tie clip, and two of the four parachutes. While it’s unclear why Cooper would have left the tie behind, it has become the biggest source of evidence for identifying him. New evidence shows that a previously unidentified particle on the tie has been identified as “titanium smeared with stainless steel”.

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How To Refrigerate With Urine

January 9, 2024 by Maya Posch 13 Comments

It’s often said that the best science experiments are the ones which do not require any special devices or ingredients, which makes the use of what naturally comes out of one’s body clearly one of the winners. It’s also the beginning of yet another [Hyperspace Pirate] chemistry video that’s both fascinating and unforgettable — this time introducing a considerable collection of urine, and the many uses of the urea in it, including its use for refrigeration.

The respective cooling effect of a variety of compounds in solution. (Credit: Hyperspace Pirate)

As icky as this may sound, it doesn’t even rank in the top ten of quaint things people have historically done with urine, so extracting urea from it is rather benign. This is performed by adding sodium hydroxide to the starting component after heating, which creates gaseous ammonia (NH₃) which was then condensed into its liquid (dissolved) form. In order to create the target compound – being ammonium nitrate – nitric acid (HNO₃) had to be created first.

For this the older, but cheaper and easier Birkeland-Eyde process was used. This uses high-voltage electrical arcs to break down the nitrogen and oxygen in the air and cause the formation of nitric oxide (NO), that subsequently reacts with atmospheric oxygen to form nitrogen dioxide (NO₂). Running the NO₂ through water then creates the desired HNO₃, which can be combined with the ammonia solution to create ammonium nitrate. The resulting solution was then evaporated into solid ammonium nitrate, to use it in an aluminium cooling cylinder, with freshly added water.

This is the simplest way to use the cooling effect of such solutions (pictured), but the benefit of ammonium nitrate over the original urea seems minimal. The low efficiency of this cooling approach means that the next use of urine will involve a much more efficient vapor-absorption cycle, which we’re sure everyone is squeezing their legs together for in anticipation.

We’ve been covering the refrigeration experiments [Hyperspace Pirate] has been conducting for some time now. If you’re into the science of making things cold check out how seashells can be turned into dry ice, or what goes into building a home cryocooler.

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Aqueous Battery Solves Lithium’s Problems

January 4, 2024 by Bryan Cockfield 15 Comments

The demand for grid storage ramps up as more renewable energy sources comes online, but existing technology might not be up to the challenge. Lithium is the most popular option for battery storage right now, not just due to the physical properties of the batteries, but also because we’re manufacturing them at a massive scale already. Unfortunately they do have downsides, especially with performance in cold temperatures and a risk of fires, which has researchers looking for alternatives like aqueous batteries which mitigate these issues.

An aqueous battery uses a water-based electrolyte to move ions from one electrode to the other. Compared to lithium, which uses lithium salts for the electrolyte, this reduces energy density somewhat but improves safety since water is much less flammable. The one downside is that during overcharging or over-current situations, hydrogen gas can be produced by electrolysis of the water, which generally needs to be vented out of the battery. This doesn’t necessarily damage the battery but can cause other issues. To avoid this problem, researchers found that adding a manganese oxide to the battery and using palladium as a catalyst caused any hydrogen generated within the battery’s electrolyte to turn back into water and return to the electrolyte solution without issue.

Of course, these batteries likely won’t completely replace lithium ion batteries especially in things like EVs due to their lower energy density. It’s also not yet clear whether this technology, like others we’ve featured, will scale up enough to be used for large-scale applications either, but any solution that solves some of the problems of lithium, like the environmental cost or safety issues, while adding more storage to an increasingly renewable grid, is always welcome.

DIY Chemistry Points The Way To Open Source Blood Glucose Testing

January 4, 2024 by Dan Maloney 16 Comments

Every diabetic knows that one of the major burdens of the disease is managing supplies. From insulin to alcohol wipes, diabetes is a resource-intensive disease, and running out of anything has the potential for disaster. This is especially true for glucose test trips, the little electrochemical dongles that plug into a meter and read the amount of glucose in a single drop of blood.

As you might expect, glucose test strips are highly proprietary, tightly regulated, and very expensive. But the chemistry that makes them work is pretty simple, which led [Markus Bindhammer] to these experiments with open source glucose testing. It’s all part of a larger effort at developing an open Arduino glucometer, a project that has been going on since 2016 but stalled in part thanks to supply chain difficulties on the chemistry side, mainly in procuring glucose oxidase, an enzyme that oxidizes glucose. The reaction creates hydrogen peroxide, which can be measured to determine the amount of glucose present.

With glucose oxidase once again readily available — from bakery and wine-making suppliers — [Markus] started playing with the chemistry. The first reaction in the video below demonstrates how iodine and starch can be used as a reagent to detect peroxide. A tiny drop of glucose solution turns the iodine-starch suspension a deep blue color in the presence of glucose oxidase.

While lovely, colorimetric reactions such as these aren’t optimal for analyzing blood, so reaction number two uses electrochemistry to detect glucose. Platinum electrodes are bathed in a solution of glucose oxidase and connected to a multimeter. When glucose is added to the solution, the peroxide produced lowers the resistance across the electrodes. This is essentially what’s going on in commercial glucose test strips, as well as in continuous glucose monitors.

Hats off to [Markus] for working so diligently on this project. We’re keenly interested in this project, and we’ll be following developments closely. Continue reading “DIY Chemistry Points The Way To Open Source Blood Glucose Testing” →

Promethean Matches: The Ancestor To Modern Matches

December 25, 2023 by Maya Posch 7 Comments

The history of making fire at will is a long and storied one, stretching back to the days when we’d rub wooden sticks together, or use flint and steel to ignite tinder. An easier, albeit vastly more expensive and dangerous alternative came in the 19th century when chemists discovered auto-ignition using a potassium chlorate mixture and sulfuric acid. This method was refined and later patented by Samuel Jones in 1828 as the ‘promethean match’ after the God of Fire, Prometheus, which is the topic of a recent [NurdRage] chemistry video.

Using practically the same recipe of potassium chlorate and sugar as in the 19th century, [NurdRage] uses paper straws to contain this powder. Glue is used to section the paper straw into two compartments and seal in the components, with the smaller compartment used for a glass capsule containing sulfuric acid. This vial was produced from the tip of a glass pipette, using a hot flame to first seal the tip, then detach and seal the other end of the tip, resulting in the sulfuric acid capsule, ready to be added to the second compartment.

The moment this glass capsule is crushed, the sulfuric acid will soak into the paper, reaching the large compartment with the potassium chlorate and sugar mixture, causing a strongly exothermic reaction that ignites the paper. Yet as simple as this sounds, [NurdRage] found the three matches he made to be rather fickle, with one igniting beautifully after crushing the capsule with pliers, while one did nothing and the remaining match decided to violently explode rather than burn.

Considering the immense manual labor involved in making these matches, they never were very popular, and were quickly replaced by strike-anywhere matches, followed by safety matches, none of which require you to carry fragile glass capsules containing sulfuric acid with you. As a chemistry experiment, it is however a total blast that will set any boring chemistry class on fire.

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Homebrew Gel Fuel Keeps The Steam Coming, Legally

December 20, 2023 by Dan Maloney 31 Comments

All it takes is one knucklehead to go and do something stupid to screw things up for everyone. We’re not exactly sure who the knucklehead is behind the recent ban on hexamine fuel tablets, but given that it’s now proscribed in the UK under the “Control of Poisons and Explosives Precursors Regulations 2023,” we expect that that story is a doozy.

So what’s hexamine, and why should we care if it’s banned? As [Markus Bindhammer] explains, hexamine is a solid fuel commonly used to power model steam engines, among myriad other uses. Its ban leaves a bit of a hole in the model steam community, which [Markus] seeks to fill with this quick and easy gel fuel chemistry project.

The “California Snowball” is a homebrew version of what’s in those solid fuel cans you see heating chafing pans at catered events, with one common brand being Sterno. [Markus] used a saturated solution of calcium acetate (6 g in 50 ml of water) and added that to 150 ml of ethanol; commercial formulations usually use methanol to prevent anyone from drinking the stuff, with varying degrees of success. The calcium acetate forms a gel that looks like whipped cream and traps the ethanol inside. The gel can be easily scooped up and spread around, and burns with a clean, smokeless flame.

It may not exactly be a “plug and play” replacement for hexamine tablets, but one does what one can. And if there’s one thing we can celebrate about model steam engineers, it’s their persistence. We got a bunch of them together last year for a Hack Chat with [Quinn Dunki], and their passion for making things move with steam was pretty impressive.

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A Transistor, But For Heat Instead Of Electrons

December 20, 2023 by Donald Papp 31 Comments

Researchers at UCLA recently developed what they are calling a thermal transistor: a solid-state device able to control the flow of heat with an electric field. This opens the door to controlling the transfer of heat in some of the same ways we are used to controlling electronics.

Heat management can be a crucial task, especially where electronics are involved. The usual way to manage heat is to draw it out with things like heat sinks. If heat isn’t radiating away fast enough, a fan can be turned on (or sped up) to meet targets. Compared to the precision and control with which modern semiconductors shuttle electrons about, the ability to actively manage heat seems lacking.

This new device can rapidly adjust thermal conductivity of a channel based on an electrical field input, which is very similar to what a transistor does for electrical conductivity. Applying an electrical field modifies the strength of molecular bonds in a cage-like array of molecules, which in turn adjusts their thermal conductivity.

It’s still early, but this research may open the door to better control of heat within semiconductor systems. This is especially interesting considering that 3D chips have been picking up speed for years (stacking components is already a thing, it’s called Package-on-Package assembly) and the denser and deeper semiconductors get, the harder it is to passively pull heat out.

Thanks to [Jacob] for the tip!