Discoveries in the Physics & Astronomy shop | Science, curiosities, and surprises
There are thunderstorms outside, but we need to do a tent check. Do we have all the pieces? Will everything fit inside as planned? If it’s necessary to set this up outdoors during an actual rainstorm, have we done our practice run?
Pick the largest and least occupied space in the building and get to work. If anyone asks, you’re doing this for science! (Technically true.)
Sometimes you find oddities whose initial and continued existence boggles the mind. This clock was gathering dust atop the bookcases in the student lounge, battery-free and long-forgotten.
Where did it come from? What life did it live before it came to Olin? Who thought enough of it to acquire, but not enough to take with them?
What should we do with it now?
If it still works, it stays in service. There’s always a bit of “what’s this?” and “what’s it do?” and “how do I make it do what it does?” when stumbling across old equipment, but that’s what we have physicists for.
LEDs can do some excellent things, primarily generating a lot of photons for very little power input, with the opportunity to have a fine degree of control over the details. Optically, though, they need a little help.
Fortunately, for our undergraduate labs in need of an adjustable light source, a spherical glass lens and an adjustable housing collimate them well enough. Which, when you need to build a lab’s worth of these things, makes life in the basement a whole lot simpler.
Remember those days? Floppy disks and cassette tapes and VHS and all those different storage media using magnetic materials, which could be corrupted or unwritten with inadvertent exposure to strong magnetic fields.
For fun, see how many modern applications still use a stylized version of the 3.5″ floppy as a “save” icon. (As of scribbling this, Microsoft Excel does.)
While exploring a potential site for measurement equipment, it’s important to keep an eye on the local wildlife. After a long time underground, those big red eyes are just taking it all in.
Not pictured: all of the other cicadas all over the place. Because where there’s one, there are bound to be many, many more. Brood XIV, maybe?
It really wasn’t that long ago that computers came equipped with optical disc drives, and they were effective means of data storage, and the density you could store on a DVD instead of a CD was pretty exciting. Now? They’re not only borderline-useless, but the features that we used to reference as a cultural touchstone are no longer obvious to our students.
It’s not that they don’t know what these are. It’s that they haven’t handled a million of them to know their dimensions, to understand the diffraction rainbow they make. The physicists around here remember using the inescapable AOL discs as cheap, readily available diffraction gratings back in grad school. The astronomers use their proportions to illustrate the shape of the Milky Way Galaxy. Students now need to physically hold one of these to get the idea, because they don’t have a mental image ready to go.
Our Galaxy, if you were wondering, is roughly proportioned as a CD, only instead of being a millimeter and a half thick, is more like 1,000 light years. Very roughly, anyway.
This is what happens when you burn a candle at both ends!
Make a pivot, light both ends, and the burning and dripping wax creates oscillations. In our limited experience, pretty irregular and chaotic. It’s really quite cool.
Here, our more modern sodium light sources, using a clever design that enabled a reduction from the minimum 35W to as little as 18W in 1977. Cool, yeah?
Unfortunately, Philips finally bowed out of the low pressure sodium lamp game in 2019, mean we’ve got these dinosaurs running for as long as we can scour spare lamps online. Once the supply’s gone, it’s gone.
Hey, look! Sodium metal! Highly reactive, so it’s inside with a mixture of 99% neon and 1% argon, neither of which deigns to react with, well, anything. That’s why, when it starts up, we see a purplish glow from the noble gases before tube reaches 260°C and vaporizes the sodium. After that, it’s an intense monochromatic yellow-orange that’s hard to look at.
Remember the old, aggressively-yellow street lighting that pre-dated LEDs, ceramic metal halide, and high pressure sodium? Turns out it’s very useful for physics, as the two strong emission lines near 589nm are handy for various experiments.
The lamps themselves are fairly tough, and the ballasts that operate them even more so. But, eventually, they burn out.
General Electric ceased production on these lamps back in 1972. So, no, sorry, replacements are not readily available.