Tag: physics

Stopper Knots

Posted on by Brian Garthwaite
Kevlar string, of course.

There are a handful of occupations and/or hobbies which reward those interested in the craft of knot-tying. The big ones include boating, camping, climbing, and fishing. (There may be hobby overlap.) Arborists, equestrians, and surgeons need specific, functional knots, too.

Turns out so do lab technicians.

We’re slowly adding knots to our repertoire, for all manner of purposes. Pictured above: a doubled-up double overhand stopper. (A single knot was insufficiently stopper-ing given the thread diameter and pendulum bobs on hand.) Alpine butterflies, bowlines, non-slip mono loops, trucker’s hitches. Now we just want an excuse to use the Double Dragon Loop!

Colorful Prizes

Posted on by Brian Garthwaite
A small selection of bright, bright colors.

Thanksgiving break is nearly upon us, and the student body is desperate to extend their week-long break into something even longer. But classes are still in session! There are still amazing and exciting things to learn!

And we have toys to give away!

Annual tradition to encourage our introductory physics to stick around: problem session prizes. Puzzle games, fidget spinners, stretchy rubber toys, and some other unidentifiable plastic oddities that came in the variety packs. It’s a literal grab-bag of eye-searingly bright toys.

Have a happy Thanksgiving break!

Doppler Ball

Posted on by Brian Garthwaite
Orange foam ball on cable
The noise is more obnoxious than the color.

An electronic buzzer buried inside a foam ball, on a long cable with a switch and handle at the end. Flick the switch, and a piercing 2,500 Hz signal begins. Whirled in a big circle around your own head, the tone persists. For everyone else in the room, it creates a cyclic Doppler shift, a repeating weeee-oooo, weeee-oooo that sticks in the brain even after it’s done, like when you see phosphene images behind your eyelids after catching a glimpse of something way too bright.

We can’t overstate the wonderful modifications to the original object, back in 2010, which added the cable and switch. Your bog-standard Doppler ball – available from several scientific apparatus purveyors – requires one to open up the ball, turn on the buzzer, then close it back up. Tossing it back and forth between students illustrates the concept.

Then, when you’ve had quite enough and just want it to stop, you have to pry it open and shut the whole thing off. (This vintage version, pre-mod, required full-on battery removal.) The Doppler ball: it teaches us all kinds of new lessons!

Fire Pit

Posted on by Brian Garthwaite
Embers in process.

S’mores! Pretty much everyone likes s’mores, and they’re a great excuse to get outside and be social. And to make a cozy fire on an October evening.

Of course, if you also attempt to do this with physicists, the discussion is bound to turn to fluid turbulence and vortices and all of that…

In case you were wondering: there is a version of this which involves watching the fluid flow with lasers, because of course they have another way to play with lasers…

Dinosaur Truck

Posted on by Brian Garthwaite
Plastic toy truck
Yes, this exists.

Considering that our course offerings cover the full range of classical mechanics, it should come as no surprise that we have many, many objects useful for demonstrating motion. Balls, cylinders, carts with low friction, blocks with high friction, carts which glide, carts which propel themselves, carts students can ride, etc. Also, just in case: a Jurassic Park-branded pickup truck.

It comes with a driver – currently leaning to their right, as if to call to someone on the passenger side of the vehicle – and a cage for the lion velociraptor. Complete with said velociraptor in the back.

Quality

Posted on by Brian Garthwaite
One-bar metallophone
You can’t tell from the photo, but the tone is lovely.

Both Physics and Astronomy courses do a lot of work with waves, and while light is one of the most important types for study, sound is exceptionally handy for demonstrations. There’s an immediacy, a feel, that can make sonic demos feel more intuitive.

We have a few of these about, metal bars with supports at the nodes of a standing wave, seated over a wooden box. The string goes where the bar doesn’t vibrate, and hence doesn’t dampen the sound, while the box helps it resonate louder. Ka-bong! They’re quite fun.

Apparatus label plate
Quality!

And, yes, Carl J. Ulrich of Minneapolis, Minnesota did some fine work here.

Battery Tester

Posted on by Brian Garthwaite
Green is good!

As one might imagine, hundreds of students in labs each semester means we use a lot of batteries. Just a ton of ’em.

Sometimes we need them at full capacity, but certain uses can be fine if they’ve started to develop some of that internal resistance after a while. Certain situations call for the higher potential current output of alkalines, while others need lithiums to keep the voltage from dropping too low. And at other times, the relative calm of a zinc-carbon battery is just perfect, like when students are building basic circuits and there’s a risk of shorting the batteries.

Much lower risk of booms and burns with the zinc-carbon.

Still, unless a battery’s in real rough shape, you never know how much juice they’ve got left just by looking. Pop one on the tester to see. When they’re almost new, you can hear the needle tap the far side!

Certificate of Quality

Posted on by Brian Garthwaite
Oh, wow, that logo!

This was a quality instrument, we’re supposing. Currently it’s a steel door, with its associated cabinet, apparatus, and everything else unaccounted for and presumed long gone. Any details associated with it have disappeared as well.

But check out that sticker! The Nuclear-Chicago Corporation made a variety of devices for nuclear radiation detection, although a cursory internet search reveals mostly hand-held items rather than cabinet-mounted equipment. Still, have a look through that fantastic mid-century aesthetic! Back in the days when uranium prospecting was what all the cool kids were doing.

They put out the model 2586 “Cutie Pie” in 1954. The Cutie Pie.

At any rate, Abbott Laboratories bought them out in 1964, so whatever device this accompanied goes back to sometime between 1954 – the name change to Nuclear-Chicago – and the 1964 sale. Should we ever stumble across the remains of it, rest assured we’ll make note of it.