Seeing Bacteria, Nanoprisms, And More With An Atomic Force Microscope

July 5, 2026 by Aaron Beckendorf 4 Comments

Unlike almost every other kind of microscope, atomic-force microscopes (AFMs) don’t use any kind of optical beam to image their subjects. Instead, they physically detect the subject’s surface with a tiny probe, repeating this thousands of times to build up a height map of the subject, sometimes with a resolution below a single nanometer. [Ben Krasnow] got to use an AFM in an investigation of one of his projects, and shared some unusual uses of it in his latest video.

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A black plastic cube is shown in front of another, larger rectangular black plastic box. The plastic cube has a silver microscope objective protruding from one side, with green light being emitted from it into a small plastic tube held on a positioning stage.

2026 Frikkin Lasers Challenge: A 3D-Printed Raman Spectrometer

July 5, 2026 by Aaron Beckendorf 19 Comments

When light reflects off a surface, not all of it reflects off at the same wavelength; some photons impart a portion of their energy to raising the vibrational energy of the surface’s molecules, and are thus scattered away at a lower energy and longer wavelength. This is called Raman scattering, and the precise wavelength shifts are characteristic of the particular molecule being illuminated. It can therefore be used in Raman spectroscopy to identify molecules; these spectrometers are normally elaborate, expensive instruments, but [Allegedly Science] was able to build a simple system with surprising sensitivity.

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Settling The Debate On Soldered Versus Crimped High-Current Connectors

July 3, 2026 by Maya Posch 82 Comments

For some reason there’s heated debate around the topic of whether high current carrying wiring ought to use crimped or soldered connections, even though the industry standard is to crimp everything. As a practical demonstration of why this is the case, [Will Prowse] set up a test involving a rig capable of dispensing a few hundred amps through both a crimped and a soldered copper cable.

Prior to making things go spicy, [Will] made sure to check the resistance of the two cables, noting that the soldered version had significantly lower resistance than the crimped connectors. This could be one metric that proponents of soldered connectors can point to as a benefit.

Of course, the main benefit of crimping is that you create a cold weld if crimped properly, which is a sold-state welding process that effectively blends two metal surfaces together. This is also why wire wrap is generally considered to be so very reliable, as it creates a gas-free, solid connection that does not rely on a softer, dissimilar material like solder to hold things together. Of note here is also that the cold weld process tends to continue for a while, so this kind of connection is likely to get better over time.

In the subsequent testing this difference is demonstrated quite well, especially when both cables are subjected to the sort of mechanical abuse that would be expected in an installation, such as vibrations and direct impacts. Here the soldered connections quickly begin to fail, resulting in one soldered connector even unsoldering itself due to heat development. Ultimately cold welding is simply superior over relying on a flimsy and capricious interface of intermetallic compounds.

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Trying Out Viewer Suggestions For Levitation On An Induction Cooker

July 1, 2026 by Maya Posch 3 Comments

Doing something once is fun, but if you get interesting feedback from viewers on how to make things even more fun, you can only follow all of these instructions and put more random objects on top of an induction cooker, as [Brainiac75] fortunately did.

Much like in the first video, the goal here is to use the Lorentz force that is induced in the object for levitation, ideally without having said object depart for orbit, melt into a puddle of molten metal or be a general hazard to anyone standing in the same room.

Some of the suggestions were rather benign, such as improving the aluminium foil ring by adding four times more layers to create more mass. Unfortunately adding more layers here had the device refuse to turn on due to the absence of a suitable ferromagnetic target. The difference between the working versions with one to three layers was here also not really noticeable. Various aluminium and copper tape configurations were then attempted, but without much success.

Of note is that while levitating, the metal gets pretty hot. At one point a CD even gets melted to aluminium foil. Even the use of water-filled aluminium cans will only give you so much time, and ramping down the power level on the induction cooker only revealed that this particular model operates only at either at full blast or off. Correspondingly a new induction cooker with claimed constant output was obtained for the next experiments at lower levels.

Interestingly, it was this new induction cooker set to a more reasonable output level that showed the first reasonably static levitation results without immediate conflagration or molten metal splatter risk. Whether this is the kind of levitation display that you want to set up in your living room in lieu of a boring magnetic one is still a good question, but at least this demonstration got downgraded to something potentially safe enough to play around with in a physics class.

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From Sugar To Ethanol Fuel With A Little Microbial Help

June 30, 2026 by Maya Posch 65 Comments

In these trying times it seems appropriate to work through some ‘what if ‘ scenarios, such as the local gas station suddenly not having any more gasoline to sell you, or said gas station ceasing to exist altogether. In that case it can be incredibly useful to be able to create your own gasoline alternative in the form of ethanol. As demonstrated by [Hyperspace Pirate] in a recent video this process is fairly straightforward once you have procured an appropriate feedstock, such as here sugar (sucrose).

Although baker’s yeast (Saccaromyces cerevisiae) is more commonly associated with the production of ethanol-laced drinks, there’s nothing that says that you cannot distill out the approximately 10-15% ethanol that results from a yeast feeding frenzy and resulting waste products.

How to do this distillation step is explained in the video, with the mixture heated and put through a self-made reflux column to deal with the fact that the water/ethanol mixture is an azeotropic mixture, meaning that a lot of water is expected to make its way out of the condenser along with ethanol without this measure to condense as much of the water vapor before it can make its way to the top of the column.

Ultimately the conversion rate of plain white sugar to ethanol is about 54%, with the rest turning into CO₂. With an appropriately converted combustion engine for running on 100% ethanol, it runs pretty well, though the final cost per liter of ethanol will heavily depend on your feedstock.

With the full costs of the electric heater of the distillation column taken into account – at 2.57 kWh/L – as well as the cost of the off-the-shelf sugar, [Hyperspace Pirate] with his Florida kWh cost of $0.12 paid around $2.62/L, or $9.91 per gallon. Even with how much prices at the gas pump have shot up recently, you’d pretty much need to find a free source of feedstock and otherwise optimize the process for it to make much sense, even in this economy.

That said, it’s crazy that the world of Mad Max doesn’t run on ethanol. If tomorrow a certain bubble were to implode and the global economy fell apart as a result, producing bioethanol would seem to be a highly marketable skill.

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How To Remove Bounce When Bouncy Objects Encounter Bounciness

June 30, 2026 by Maya Posch 7 Comments

We all love a good bit of bounce now and then, with everything from trampolines to bouncy castles and bouncy balls forming the staple of a wholesome childhood for many. That said, most of our bouncy experiences in day to day life concern bouncy objects that meet immovable or rigid objects, including said child having a blast in a bouncy castle. Where the physics get arguably more interesting and less intuitive is when you combine two objects that are both bouncy, with [Steve Mould] recently taking a look at the tuning of said bounciness to even kill the bounce completely.

Understanding how to achieve this tuning means understanding how the kinetic energy is stored in each flexible material, and how to dissipate it in a way that doesn’t result in the aforementioned bounciness. In the simple physical demonstration setup the addition or removal of weights to the lower sprung platform tunes the response to the bouncy ball that is dropped on top of it.

After going through the science behind bounciness and springiness using the practical application of this science in the context of golf balls and clubs, [Steve] introduces the simulation tool that he created. This allows you to tweak the parameters of such a double spring system, which may bring back some high school physics lessons for some.

In a system like that of a golf club and the ball, having undesirable oscillations (bouncing) reduces the final kinetic energy transferred to the ball. Although ‘bouncy’ is perhaps not the first thought that comes to mind when handling a golf ball or a club, ultimately they are just as bouncy as a bouncy ball or an electric switch, just on their own scales, with their own opportunities for optimization and analysis.

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Retro Gear And The Mystery Of Cables Melting Into Cases While In Storage

June 30, 2026 by Maya Posch 26 Comments

The phenomenon of cable-shaped indents in the plastic cases of retro systems is one that’s probably painfully familiar to many a collector of such systems. Although in these situations neither side got hot enough to cause any melting – especially while disconnected in storage – it still has that same melted appearance. The real cause here is not heat, but plasticizer migration, as detailed in a recent video by [Run Stop Restored] over on YouTube.

Plasticizers are an additive to many plastics that aim to make it more flexible (‘plastic’), as well as improve other characteristics of the base material, with PVC in particular relying on plasticizers to give it its desired properties for applications where PVC has to be flexible. Here the flexible cable insulation of these devices generally uses PVC, which over time can migrate to other polymers when brought into close contact for extended periods of time.

The – usually ABS – enclosures of e.g. Commodore tape drives as in this video demonstration thus get correspondingly inundated with the same type of plasticizers that ABS is also highly susceptible to. Since in storage the cables tend to be wrapped – tightly – around the device they’re attached to, this results in a solid contact which thus enables this gradual process to work its magic, whether it’s a Commodore datasette or a power supply brick.

Correspondingly the PVC insulation becomes brittle as it loses its plasticizer, with the process sped up by higher environmental temperatures. To prevent this, never wrap a PVC cable around a device, and keep it physically separated from susceptible plastics like ABS as much as reasonably possible. Along with a cool environment this should prevent plasticizer migration from ruining what used to be a pristine case.

This problem is particularly significant for retro gear from the 1980s and thereabouts, before phthalate-free plasticizer alternatives were developed, along with other changes such as more stable formulations that prevent this migration process. Adding a coating can also help, especially for protecting older gear, but flexible PVC in particular should be viewed with suspicion and treated carefully.

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