Hats off to [Paul Brooking] as he shows off his homemade mass spectrometer in two recent videos you can see below. The first video demonstrates that the device works. The second video shows details about how it was made.
It’s not a good starter project, requiring quite a bit of sophisticated gear including two-stage vacuum pumps, Peltier cold plates, and ion sources, but if you aren’t familiar with mass spectrometers the basic idea is simple enough. You take a sample and bombard it with electrons. This creates a stream of ions of the component parts of the sample. Ions of heavy elements, obviously, weigh more than ions of lighter elements. A magnetic field deflects the ions, and the lighter ones are deflected more than the heavier ones. By detecting ions at a certain spot in the deflected beam, you can determine the relative amount of ions at a certain mass.
Despite being present in everything that contains water, tritium is not an isotope that many people were that familiar with outside of select (geeky) channels, such as DEF CON with a tritium-containing badge, the always excellent NurdRage’s assembly of a tritium-based atomic battery, or the creation of a tritium-phosphor-based glow-in-the-dark tesseract cube.
Tritium is a hydrogen isotope that shares a lot of characteristics with its two siblings: 1H (protium) and 2H (deuterium), with the main distinction being that tritium (3H) is not a stable isotope, with a half-life of ~12.32 years that sees it decay into 3He. Most naturally occurring tritium on Earth originates from interactions between fast neutrons (>4.0 MeV) from cosmic radiation and atmospheric nitrogen.
Recently tritium has become a politically hot topic on account of the announced release of treated water at the Japanese Fukushima Daiichi nuclear plant. This has raised for many the question of just how much tritium is ‘too much’ and what we’re likely to notice from this treated — but still tritium-containing water — being released into the ocean.
You’ve probably heard the term magnetic gradient before, but have you ever seen one? Now you can in [supermagnetman’s] video, below. The key is to use very fine (2 micron) iron filings and special silicone oil. The video is a good mix of whiteboard lectures and practical hands-on experimenting. Just watching him spin the iron filings in the bottle was entertaining. There’s sources in the video description for the oil and the filings if you want to replicate the demonstrations for a classroom or just for your own enjoyment.
It’s one thing to know the math behind magnetic fields. It’s another to be able to use them in practical applications. But a good understanding of the physical manifestation of the magnetic field coupled can help clarify the math and vice versa. There’s a lot of common sense explanations too. For example, the way the filings accelerate as they get closer to the magnet explains why the patterns form the way they do. Iron filings are a traditional way to “see” magnetic fields. Ask anyone who ever had a Wooly Willy.
Iron filings can be fun to play with, although we don’t think we’ve ever had any this fine. If you prefer your magnetic field visualizations to be higher-tech, we have the answer.
Growing up in Montana I remember looking out at night and seeing the Milky Way, reminding me of my insignificance in the universe. Now that I live in a city, such introspection is no longer easy, and like 1/2 of humanity that also lives in urban areas, I must rely on satellites to provide the imagery. Yet satellites are part of the problem. Light pollution has been getting worse for decades, and with the recent steady stream of satellite launches and billionaire joyrides we have a relatively new addition to the sources of interference. So how bad is it, and how much worse will it get?
Looking up at the night sky, you can usually tell the difference between various man-made objects. Planes go fairly slowly across the sky, and you can sometimes see them blinking green and red. Meteors are fast and difficult to see. Geostationary satellites don’t appear to move at all because they are orbiting at the same rate as earth’s rotation, while other orbit types will zip by.
SpaceX has committed to reducing satellite brightness, and some observations have confirmed that new models are a full magnitude darker, right at the threshold of naked-eye observation. Unfortunately, it’s only a step in the right direction, and not enough to satisfy astronomers, who aren’t looking up at the night sky with their naked eyes, naturally.
The satellites aren’t giving off the light themselves. They are merely reflecting the light from the sun back to the earth, exactly the same way the moon is. Thus something that is directly in the shadow of the Earth will not reflect any light, but near the horizon the reflection from the satellites can be significant. It’s not practical to only focus our observatories in the narrow area that is the Earth’s shadow during the night, so we must look closer to the horizon and capture the reflections of the satellites. Continue reading “Things Are Looking Brighter! But Not The Stars”→
Our world is constantly bombarded by high-energy particles from various sources, and if they hit in just the right spot on the sensitive electronics our modern world is built on, they can start flipping bits. Known as Single Event Upsets (SEU), their effect can range from unnoticeable to catastrophic, and [Veritasium] explores this phenomenon in the video after the break.
The existence of radiation has been known since the late 1800s, but the effect of low-level radiation on electronics was only recognized in the 1970s when trace amounts of radioactive material in the ceramic packaging of Intel DRAM chips started causing errors. The most energetic particles come from outer space and are known as cosmic rays. They originate from supernovas and black holes, and on earth they have been linked to an impossibly fast Super Mario 64 speedrun and a counting error in a Belgian election. It’s also possible to see their path using a cloud chamber you can build yourself. There are even research projects that use the camera sensors of smartphones as distributed cosmic ray detectors.
Earth’s magnetic field acts as a protective barrier against the majority of these cosmic rays, and there is a measurable increase in radiation as you gain altitude and enter space. In space, serious steps need to be taken to protect spacecraft, and it’s for this reason that the Perseverance rover that landed on Mars this year uses a 20-year-old main computer, the PowerPC RAD750. It has a proven track record of radiation resistance and has been used on more than a dozen spacecraft. Astronauts experience cosmic radiation in the form of flashes of light when they close their eyes and protecting their DNA from damaging effects is a serious concern for NASA.
There’s something intrinsically simple about the concept of carbon (CO2) capture: you simply have the CO2 molecules absorbed or adsorbed by something, after which you separate the thus captured CO2 and put it somewhere safe. Unfortunately, in physics and chemistry what seems easy and straightforward tends to be anything but simple, let alone energy efficient. While methods for carbon capture have been around for decades, making it economically viable has always been a struggle.
This is true both for carbon capture and storage/sequestration (CCS) as well as carbon capture and utilization (CCU). Whereas the former seeks to store and ideally permanently remove (sequester) carbon from the atmosphere, the latter captures carbon dioxide for use in e.g. industrial processes.
Recently, Pacific Northwest National Laboratory (PNNL) has announced a breakthrough CCU concept, involving using a new amine-based solvent (2-EEMPA) that is supposed to be not only more efficient than e.g. the previously commonly used MEA, but also compatible with directly creating methane in the same process.
If you want to track a snail, you need a tiny instrumentation package. How do you create an entire data acquisition system, including sensors, memory, data processing and a power supply, small enough to fit onto a snail’s shell?
Throughout history, humans have upset many ecosystems around the world by introducing invasive species. Australia’s rabbits are a famous example, but perhaps less well-known are the Giant African land snails (Lissachatina fulica) that were introduced to South Pacific islands in the mid-20th century. Originally intended as a food source (escargot africain, anyone?), they quickly turned out to be horrible pests, devouring local plants and agricultural crops alike.
Not to be deterred, biologists introduced another snail, hoping to kill off the African ones: the Rosy Wolfsnail (Euglandina rosea), native to the Southeastern United States. This predatory snail did not show great interest in the African intruders however, and instead went on to decimate the indigenous snail population, driving dozens of local species into extinction.
A Rosy Wolfsnail carrying a light sensing Micro Mote on its back. Source: Cindy S. Bick et al., 2021
One that managed to survive the onslaught is a small white snail called Partula hyalina. Confined to the edges of the tropical forests of Tahiti, biologists hypothesized that it was able to avoid the predators by hiding in sunny places which were too bright for E. rosea. The milky-white shells of P. hyalina supposedly protected them from overheating by reflecting more sunlight than the wolf snails’ orange-brown ones.
This sounds reasonable, but biologists need proof. So a team from the University of Michigan set up an experiment to measure the amount of solar radiation experienced by both snail types. They attached tiny light sensors to the wolf snails’ shells and then released them again. The sensors measured the amount of sunlight seen by the animals and logged this information during a full day. The snails were then caught again and the data retrieved, and the results proved the original hypothesis.
