Citizen Science By The Skin Of Your Teeth

If you are a schoolkid of the right age, you can’t wait to lose a baby tooth. In many cultures, there is a ritual surrounding it, like the tooth fairy, a mouse who trades your tooth for a gift, or burying the tooth somewhere significant. But in 1958, a husband and wife team of physicians wanted children’s teeth for a far different purpose: quantifying the effects of nuclear weapons testing on the human body.

A young citizen scientist (State Historical Society of Missouri)

Louise and Eric Reiss, along with some other scientists, worked with Saint Louis University and the Washington School of Dental Medicine to collect and study children’s discarded teeth. They were looking for strontium-90, a nasty byproduct of above-ground nuclear testing. Strontium is similar enough to calcium that consuming it in water and dairy products will leave the material in your bones, including your teeth.

The study took place in the St. Louis area, and the results helped convince John F. Kennedy to sign the Partial Nuclear Test Ban Treaty.

They hoped to gather 50,000 teeth in a year. By 1970, 12 years later, they had picked up over 320,000 donated teeth. While a few kids might have been driven by scientific altruism, it didn’t hurt that the program used colorful posters and promised each child a button to mark their participation.

Children’s teeth were particularly advantageous to use because they are growing and are known to readily absorb radioactive material, which can cause bone tumors.

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DIY Strontium Aluminate Glows In The Dark

[Maurycyz] points out right up front: several of the reagents used are very corrosive and can produce toxic gasses. We weren’t sure if they were trying to dissuade us not to replicate it or encourage us to do so. The project in question is making strontium aluminate which, by the way, glows in the dark.

The material grows strongly for hours and, despite the dangers of making it, it doesn’t require anything very exotic. As [Maurycyz] points out, oxygen and aluminum are everywhere. Strontium sounds uncommon, but apparently, it is used in ceramics.

For the chemists among us, there’s an explanation of how to make it by decomposing soluble nitrate salts. For the rest of us, the steps are to make aluminum hydroxide using potassium alum, a food preservative, and sodium hydroxide. Then, it is mixed with nitric acid, strontium carbonate, europium, and dysprosium. Those last elements determine the color of the glow.

A drying step removes the acid, followed by dissolving with urea and water. The heat of the reaction wasn’t enough to form the final product, but it took time with an oxy-propane torch to form blobs of strontium aluminate. The product may not have been pure, because it didn’t glow for hours like commercial preparations. But it did manage to glow for a few minutes after light exposure.

We try to limit our chemistry to less toxic substances, although ferric chloride can make a mess. You could probably track down the impurities with a gas chromatograph. What we really want is a glow-in-the-dark car antenna.

Hacking The Ionosphere, For Science

Imagine what it must have been like for the first human to witness an aurora. It took a while for our species to migrate from its equatorial birthplace to latitudes where auroras are common, so it was a fairly recent event geologically speaking. Still, that first time seeing the shimmers and ribbons playing across a sky yet to be marred by light pollution must have been terrifying and thrilling, and like other displays of nature’s power, it probably fueled stories of gods and demons. The myths and legends born from ignorance of what an aurora actually represents seem quaint to most of us, but it was as good a model as our ancestors needed to explain the world around them.

Our understanding of auroras needs to be a lot deeper, though, because we now know that they are not only a beautiful atmospheric phenomenon but also a critical component in the colossal electromagnetic system formed by our planet and our star. Understanding how it works is key to everything from long-distance communication to keeping satellites in orbit to long-term weather predictions.

But how exactly does one study an aurora? Something that’s so out of reach and so evanescent seems like it would be hard to study. While it’s not exactly easy science to do, it is possible to directly study auroras, and it involves some interesting technology that actually changes them, somehow making the nocturnal light show even more beautiful.

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