Rapid-Reload Vacuum Cannon Totally Demolishes Those Veggies

January 14, 2022 by Dave Rowntree 9 Comments

[NightHawkInLight] has been developing his design for a vacuum canon for a while now, so it seems fitting to drop in check out the progress. The idea is pretty straightforward, take a long rigid tube, insert a close fitting piston, magnetically attached to a projectile, and stopper the open end with something easily destroyed. The piston needs to be pulled into the tube with some force, to pull a vacuum against the stopper. The interesting bit happens next, when the piston exits the other end of the tube, with the vacuum at its maximum, there is a sudden inrush of air. Apparently this inrush of supersonic velocity, and the momentum of the mass of air is sufficient to eject the projectile at considerable velocity, smashing through the plug and demolishing the target. So long as the target is of the soft and squishy variety anyway.

It’s an interesting idea, and certainly gives plenty of bang for not many bucks. That big lump of acrylic tubing (presumably used for ease of explanation in the video) looks fairly expensive to buy off the shelf, but we reckon any old pipe would probably work out fine.

We’ve definitely covered our share of DIY projectile weapons, like this air cannon made from PVC pipe parts, and of course there’s this crazy big one, that you should definitely not try at home.

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This DIY Microscope Design Is All Wet

January 14, 2022 by Al Williams 5 Comments

[Robert Murray-Smith] wanted to recreate how some ancient microscopes worked: with a drop of water as a lens. The idea is that the meniscus of a drop of water will work as a lens. This works because of surface tension and by controlling the attraction of the water to the surface, you can actually form convex and concave surfaces.

What’s interesting is that this doesn’t require a lot of equipment. Some plastic, a hole punch, some pens, a flashlight, and some other odds and ends. Then it’s just a matter of grabbing some puddle water and examining the critters inside. Of course, with a single lens, these are more properly magnifying glasses. Some claim that people in China built such instruments thousands of years ago. [Robert] mentions [Antonie van Leeuwenhoek] as the father of the microscope, although he wasn’t the first to build such a device. He did create amazing glass lenses using a method he kept secret but has been worked out using modern science.

It is hard to see much through the camera, but it clearly was magnifying. Not a bad little rainy day kid’s project since you probably have everything you need on hand. We wonder what other readily-available things you could image with a device like this.

Of course, if you want to build a real microscope, the designs are out there. You can even make one using — mostly — LEGO.

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Illuminating Origami Is Just Around The Corner

January 12, 2022 by Michael Shaub 14 Comments

Pop-up greeting cards are about to get a whole lot more interesting. Researchers at Seoul National University in Korea have created glowing 3D objects with a series of prototypes that fold thin QLED (Quantum Dot LED) sheets like origami. They used a CO₂ laser to etch “fold lines” in the QLED so the sheets could be formed into 3D shapes. The bends are actually rounded, but at 5μm they appear to be sharp corners and the panels continue to illuminate across the fold lines for at least 500 folds. Some glow in solid colors, while others use smaller addressable areas to create animated matrix displays of patterns and letterforms. See the short video after the break, read the Physics World article or to see all the prototypes and dig into details of the full research paper in Nature (freed from the paywall by SharedIt).

Folded QLED Panels – forming a pyramid and a cube

Folded QLED Panels – various patterns and the 3D forms they fold into

We’re not sure how soon this technique can be duplicated in our home labs, but we can’t wait to fold up our own 3D lights and matrices. Until then, check out some glowing origami you can make right now from [Charlyn Gonda] at Remoticon 2020 and earlier that year and this amazing origami lamp.

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Regenerative Medicine: The Promise Of Undoing The Ravages Of Time

January 12, 2022 by Maya Posch 15 Comments

In many ways, the human body is like any other machine in that it requires constant refueling and maintenance to keep functioning. Much of this happens without our intervention beyond us selecting what to eat that day. There are however times when due to an accident, physical illness or aging the automatic repair mechanisms of our body become overwhelmed, fail to do their task correctly, or outright fall short in repairing damage.

Most of us know that lizards can regrow tails, some starfish regenerate into as many new starfish as the pieces which they were chopped into, and axolotl can regenerate limbs and even parts of their brain. Yet humans too have an amazing regenerating ability, although for us it is mostly contained within the liver, which can regenerate even when three-quarters are removed.

In the field of regenerative medicine, the goal is to either induce regeneration in damaged tissues, or to replace damaged organs and tissues with externally grown ones, using the patient’s own genetic material. This could offer us a future in which replacement organs are always available at demand, and many types of injuries are no longer permanent, including paralysis. Continue reading “Regenerative Medicine: The Promise Of Undoing The Ravages Of Time” →

An Oil Diffusion Vacuum Pump From Thrift Store Junk

January 12, 2022 by Dan Maloney 14 Comments

It seems like creating a vacuum should be a pretty easy job, but it turns out that sucking all the air out of something is harder than it seems. A cheap vacuum pump will get you part of the way there, but to really pull a hard vacuum, you need an oil diffusion pump that costs multiple tens of thousands of dollars.

Or, you need a bunch of thrift store junk, a TIG welder, and a can of WD-40. At least that’s what [Lucas] put into his homebrew oil diffusion pump. The idea of such a contraption is to vaporize oil in a chamber such that the oil droplets entrain any remaining gas molecules toward an exhaust port. His low-budget realization of this principle involved a lot of thrift store stainless steel cookware, welded together with varying degrees of success, with liberal applications of epoxy to seal up any leaks. And an electric smores cooker for the heating element, which was a nice touch. The low-budget approach extended even to the oil for the pump; rather than shelling out for expensive specialty oil, [Lucas] distilled some from a WD-40 silicone spray lubricant.

The video below details all the travails [Lucas] encountered along the way, plus the testing process. The results were at least encouraging — the diffusion pump was pulling vacuum far in excess of what the roughing pump was capable of. He clearly still has some work to do, but getting as far as he did with the scrap heap of parts he cobbled together is pretty impressive.

[Lucas]’ goal with all this? A fusion reactor. No, not that kind. This kind. Continue reading “An Oil Diffusion Vacuum Pump From Thrift Store Junk” →

Honda Ignition Coils Sing The Song Of Their People

January 11, 2022 by Tom Nardi 7 Comments

High-voltage experimenters have been using automotive ignition coils to generate impressive sparks in the home lab for decades, and why not? They’re cheap, easily obtainable, and at the end of the day, producing sparks is literally what they’re designed to do. But that doesn’t mean there isn’t room for improvement.

In his latest Plasma Channel video [Jay Bowles] revisits this classic experiment, bringing to bear the considerable high-voltage experience he’s gained over the last several years. Building on an earlier setup that used a single Honda ignition coil, this new dual-coil version can produce up to 60,000 volts and is driven by a cleaner and more reliable circuit based on the iconic 555 timer. A pair of potentiometers on the front of the driver can adjust its square wave output from 1 to 10 kilohertz manually, while a commercial Bluetooth audio receiver tied into the 555 circuit allows the output to be modulated by simply playing audio from a paired device.

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How Do Capacitors Work?

January 6, 2022 by Al Williams 6 Comments

If you are like [The Science Asylum], you might wonder how a capacitor can work since, at their core, they are nothing more than a gap filled with air or another insulator. He explains how in a recent video you can see below.

Of course, at DC, a capacitor doesn’t conduct any better than the insulator used as its dielectric. However, a DC voltage has to start sometime and when it does, it briefly looks like AC. The video explains it all in simple terms. Of course, if you are math savvy, you can probably get as much out of the normal C=dQ/dV equation.

If that doesn’t speak to you, the explanation in the video about charges will shed some light. He even shows an animation of the classic “hydraulic model”, which is helpful to develop intuition about the process.

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