Category: Uncategorized

Bubbles

Posted on by Brian Garthwaite
Billion bubble fluid label.
“A Superior Bubble Fluid”

Do you need some superior bubbles? If you’re in the time window between 1961 and 1991, Better Bubbles, Inc. of North Hollywood, Calif., has got you covered. Or, if you’re like us, and you happen to have some of this stuff still around.

Better Bubbles went out of business 32 years ago, so once we’re out of this fluid, we’re out. It is, to be honest, quite superior to the usual soap bubble liquid for kids, at least as far as creating durable thin-film interference patterns. We work diligently to minimize any actual bubbles.

Of special note: the directions for use. The label says “Do Not Dilute,” which seems an odd choice as this stuff flows like thickened liquid dish soap on an icy morning. The lid asks not only for dilution, but actual shaking, which can only result in a I Love Lucy-esque eruption of unending soap bubbles. A hand-written note – clearly the tested and preferred method, and the one still in use – calls for approximately 1 : 10 dilution (vigorously underlined!) with water.

50mL per year, diluted, gently stirred, and the remainder saved for the future. Good luck, whoever needs to find a replacement. Superior bubble fluid is rare stuff.

Bubble solution cap.
THIS is how to make a billion bubbles. Do not do this.

Old Electronics

Posted on by Brian Garthwaite
Old stuff, destined for the dump.
A pile of decrepit victory.

In the process of clearing space, you come across all manner of ancient and fascinating things. Desktop computers. Inkjet printers. CRT televisions. Slide projectors. Old motors and control gear to approximate sidereal motion.

Well, okay, reverse sidereal motion. The reason telescope mounts cost more than telescopes, because keeping stars and deep sky objects fixed in the field of view is no small task.

We’ll pop some of these open, gut ’em for any good parts, and move the remainder on to e-recycling. It’s the cycle of e-life!

Hand Riveter

Posted on by Brian Garthwaite
Pop rivet tool.
Orange handles are a nice touch.

Pop rivets haven’t seen much use in the shop of late, but they always remain an option. You put one in the nosepiece of the tool, slide through a pre-drilled hole, and squeeze the handles. That action draws the rod and bead back to the tool, deforming the rivet to compress your materials together as the bead on the far side “pops” off. Can be handy, especially when you can’t access the other side of something easily.

This one was acquired at the tail end of the 1970s, for the not-insignificant sum of $25, or $100.54 today. You can pick up the equivalent tool from McMaster-Carr with delivery tomorrow for $31.25 plus shipping, whatever that tells you about the current state of the economy. Don’t read too much into it.

Etching on rivet tool.
August, ’79. Nice vintage.

Note that the handle has also been etched with “Consumer Bargain,” which is cryptic and delightful. Clearly, this was a steal.

Constellations

Posted on by Brian Garthwaite
Triangulum on a celestial globe.
Triangulum, the Triangle.

For the most part, deciding on constellations is hard. A few really stand out (Orion, Cassiopeia) as do a number of bold asterisms (the Big Dipper in Ursa Major, the Teapot in Sagittarius). The rest of the sky, where there are stars but no super-obvious pattern stands out? Oof.

Picking all 88 sounds like a beastly challenge.

Still… sometimes it seems like someone just starting phoning it in in the end.

Triangulum and Norma on a celestial globe.
Norma, the Square, and a second Triangulum.

Declaring Norma to be a carpenter’s square isn’t helping your case.

Neodymium magnets

Posted on by Brian Garthwaite
Cube of cylinders: squaring the circle?

‘Tis that most joyous of days in the beginning of the semester: physics toy kit day! A bag full of odds and ends, perfect for playing, experimenting, and providing tactile bits to use when working through physics problems. Batteries, compasses, various wires, polarizing filters, nails, magnets, and balloons. Always balloons.

Each kit contains two small neodymium magnets, because magnets are amazing. First, you’re bound to stick them together, then spin one around and feel them repel. Surprisingly strong such wee little cylinders. Then check what they stick to around you: whether or not they feel attracted to stainless steel is always intriguing. (The answer is: depends on the type of steel and how it was formed.) Stick them together across a string and let it hang: you’ve built a compass!

Pay attention to the time and location of the sun – or Polaris if you’re pulling an all-nighter – and you can tell which pole of your magnets is which. Maybe it’ll come in handy?

Beats

Posted on by Brian Garthwaite
wobblewobblewobble

In acoustics, there’s a phenomenon known as beats, which is when two similar tones generate an interference pattern that sounds like a pulsing beat. It happens with waves of all kinds, waves being moving energy and all that, but sometimes it’s easier to really get the sensation when you hear it. Graphing out the sinusoids and showing the constructive and destructive interference helps explain it. Hearing that wubwubwubwubwub cements it.

We have what looks, at first glance, like a glockenspiel, with its metal bars all in a row. Tap one with the mallet, and it sounds almost the same as the one next to it. Almost. Tap two at once, and you get the beats.

At one end, it’s 440 Hz. Then 439, 438, 437, 436, and 435 Hz. Not only can you hear the beats, but you can very clearly hear the change in beat frequency as you combine tones in different combinations. It’s very cool.

Also quite unnerving after a while. woobwoobwoobwoobwoob

Views

Posted on by Brian Garthwaite
View from the Observatory rooftop.
Mmm. Gravel.

It’s only one story up, and not the highest open view on campus, but the view from the top of the Observatory roof is special in one important way: virtually no one else gets to climb up and take in the sights.

On a breezy January day, it’s best to make one’s appreciation brief, sun or no sun. Brrr.