Science

1280 Articles

Co-Extrusion Carbon Fiber FDM Filament Investigated

January 7, 2026 by 7 Comments

After previously putting carbon fiber-reinforced PLA filament under the (electron) microscope, the [I built a thing] bloke is back with a new video involving PLA-CF, this time involving co-extrusion rather than regular dispersed chopped CF. This features a continuous CF core that is enveloped by PLA, with a sample filament spool sent over by BIQU in the form of their CarbonCore25 filament.

In the previous video chopped CF in PLA turned out to be essentially a contaminant, creating voids and with no integration of the CF into the polymer matrix. Having the CF covered by PLA makes the filament less abrasive to print, which is a definitely advantage, but does it help with the final print’s properties? Of note is that this is still chopped CF, just with a longer fiber length (0.3-0.5 mm).

Samples of the BIQU filament were printed on a Bambu Lab H2D printer with AMS. In order to create a clean fracture surface, a sample was frozen in liquid nitrogen to make it easy to snap. After this it was coated with gold using a gold sputtering system to prepare it for the SEM.

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Faraday Effects Emerging From The Optical Magnetic Field

January 6, 2026 by 15 Comments

As an electromagnetic radiation phenomenon, it’s perhaps not so surprising that light is affected by a magnetic field. This Faraday effect (FE) has been used since its discovery by [Michael Faraday] in 1845 for a wide range of applications, allowing for the manipulation of light’s polarization, something which is very useful in the field of optics, for remote sensing and spintronics. Despite this being such a well-known property of EM radiation a recent study claims to have made a new discovery here, with what they claim is about the ‘optical magnetic field’.

Their central claim is that it is not just the electrical component that contributes to the FE, but also the magnetic one, due to Zeeman energy that expresses itself from the magnetic component as a form of inverse FE. Based on their experimental findings they estimate that it contributes to the final measured FE by about 17% at a wavelength of 800 nm.

While definitely a very niche physics paper, and with no immediate implications, if independently confirmed it could deepen our understanding of the Faraday effect, and how to use it in future technologies.

Close-Up Look Reveals That Raindrops Are More Erosive Than Assumed

January 5, 2026 by 18 Comments

Whenever it rains, people generally don’t look too closely at what the drops do exactly when they hit a surface. We generally assume that stuff will get wet and depending on the slope of the surface it’ll run off downhill at some point, probably in a nice, neat flow. Of course, reality doesn’t work that way, as Swiss researchers recently found when they pointed high-speed cameras at simulated raindrops. Their findings were published recently in Applied Physical Sciences, which is sadly paywalled, but the summary article over at phys.org provides some details, including a video.

The researchers set up a 1.2 meter long dry silicate sand surface with a 30° slope on which the drops were released. In the top image you can see two stills of the result, with the full video showing the drops turning into either peanut- or doughnut-shaped forms that gathered significant amounts of sand grains. These grains mix with the water, allowing a single drop to erode significant amounts of material from a slope, more than was previously assumed in existing soil erosion models.

Beyond erosion, these findings also offer insights for similar dynamics in other fields, all thanks to a group of researchers who got curious during a rainy walk and decided to take a closer look.

Illustration of Chladni's technique for producing his figures, from John Tyndall's Sound (1869)

Popular Science Experiments In Sound During The 19th-Century

January 5, 2026 by 13 Comments

Check one, two; check one, two; is this thing on? Over on The Public Domain Review [Lucas Thompson] takes us for a spin through sound, as it was in Britain around and through the 1800s.

The article begins by introducing the Father of Acoustics, German physicist Ernst Chladni. After placing grains of sand on a thin metal plate and drawing a violin bow along one edge Chladni figures appear, making manifest that which previously could only be heard, that is, sound waves.

It’s fun to think that it wasn’t so long ago that the physics of sound was avant-garde. Middle class Victorian society was encouraged to reproduce cutting edge experiments with equipment in their own homes, participating in a popular science which was at the same time part entertainment and part instruction, for young and old alike. Throughout the rest of his article [Lucas] lists a number of popular science books from the period and talks a little about what was to be found within.

See the video below the break for a demonstration of Chladni figures from The Royal Institution. Of course the present state of the art regarding sonics is well advanced as compared with that of the 19th century. If you’re interested to know more check out Building A Wall-Mounted Sound Visualizer and Seeing Sound For Under $200.

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Virus-Based Thermoresponsive Separation Of Rare-Earth Elements

December 31, 2025 by 9 Comments

Although rare-earth elements (REEs) are not very rare, their recovery and purification is very cumbersome, with no significant concentrations that would help with mining. This does contribute to limiting their availability, but there might be more efficient ways to recover these REEs. One such method involves the use of a bacteriophage that has been genetically modified to bind to specific REEs and release them based on thermal conditions.

The primary research article in Nano Letters is sadly paywalled, but the supporting information PDF gives some details. We can also look at the preceding article (full PDF) by [Inseok Chae] et al. in Nano Letters from 2024, in which they cover the binding part using a lanthanide-binding peptide (LBP) that was adapted from Methylobacterium extorquens.

With the new research an elastin-like peptide (ELP) was added that has thermoresponsive responsive properties, allowing the triggering of coacervation after the phages have had some time in the aqueous REE containing solution. The resulting slurry makes it fairly easy to separate the phages from the collected REE ions, with the phages ready for another cycle afterwards. Creating more of these modified phages is also straightforward, with the papers showing the infecting of E. coli to multiply the phages.

Whether the recovery rate and ability to scale makes it an economically feasible method of REE recovery remains to be seen, but it’s definitely another fascinating use of existing biology for new purposes.

Photographing Cosmic Rays With A Consumer Camera

December 28, 2025 by 18 Comments

The reason photographic darkrooms are needed is because almost any amount of light can ruin the film or the photographic paper before they are fixed. Until then these things are generally kept in sealed, light-proof containers until they are ready to be developed. But there are a few things that can ruin film even then, most notably because some types of film are sensitive to ionizing radiation as well as light. This was famously how [Henri Becquerel] discovered that uranium is radioactive, but the same effect can be used to take pictures of cosmic rays.

In [Becquerel]’s case, a plate of photographic material was essentially contaminated from uranium by accident, even though the plate was in a completely dark area otherwise. Cosmic rays are similar to this type of radiation in that they are also ionizing and will penetrate various materials even in places we might otherwise think of as dark. For this artistic and scientific experiment, [Gabriel] set up a medium-format digital camera in a completely dark room and set it to take a 41-minute exposure. The results are fairly impressive and are similar to [Becquerel]’s experiment except that [Gabriel] expected to see something whereas the elder scientist was more surprised.

Like cosmic rays or radiation from uranium, there is a lot flying around that is invisible to the human eye but that can be seen with the right equipment and some effort. Although [Gabriel] is using a camera with a fairly large sensor that we might not all have access to, in theory this could work with more off-the-shelf digital photography equipment or even film cameras. A while ago we even saw a build that used UV to see other invisible phenomena like electrical arcing.

What To Do When Your Foucault Pendulum Stops Swinging

December 27, 2025 by 41 Comments

At the Houston Museum of Natural Science they recently made a disturbing discovery: their Foucault pendulum had stopped swinging for the first time since its installation in the 1970s. (Video, embedded below.)

While some might take this as yet another sign of the end times, here it is simply a sign that the electromagnetic system that kicks the pendulum developed a fault and will need to be fixed.

Their explainer video of this Herzstein Foucault pendulum is also worth watching, as it explains both the underlying physics and this particular pendulum’s construction. Every 48 hours the 81.6 kg heavy pendulum completes a full rotation, like clockwork, with pins along the circumference being tipped over one by one as the pendulum precesses.

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