I’m populating my office with interesting sciency things. I’ve got prisms and defraction grattings in my window. I’ve built an analemma on my wall so I can tell what day it is. I have a ‘drinking bird’ going and I have a small digital microscope with a hay infusion.
So I’m looking for other things. I’d tend to avoid things that require a guest to do a lot of activity, plus it should be eye-catching and not messy…so vinegar volcanoes are out.
I’ve thought of floating a golf ball in a column 1/2 filled with salt water/fresh water; if I had the equipment I might consider it.
Nitpick – “diffraction gratings”, not “defraction gratings”.
Edmunds used to sell a nifty little book about how to make interesting viewers from prisms – items that showed one picture when you looked in at one angle, one at another.
I’d suggest a radiometer ( Radiometer - Wikipedia ) , especially if you get direct sun during part of the day.
A gyroscope and stand (and you can make a nifty inexpensive gyroscope if you buy a Fidget Spinner – I picked up several at $1 apiece recently. Glue a nail to the hub, sticking straight out. If you spin it fast, you can support it, apparently against gravity, from a loop of string around that nail.)
Fill a bottle with mineral oil and iron filings, and it’ll make magnetic field patterns if you bring a magnet close.
Get some Liquid Crystal thermal paper from Edmund Scientifics or elsewhere – it’ll color from the temperature of your hand.
Yoshimoto Cubes. While 1 is fun 2 or more are even funner. Available from Amazon, of course along with similar weird folding 3-D cubical/triangular things.
A pair of parabolic mirrors, in fact. They’re placed so that the focus of each is at the center of the opposite one (not with the two foci coincident, which is what you’d expect). The original was called the “Mirage” device. It was discovered by accident by a couple of guys playing with war-surplus equipment. I wrote an article about it for Optics and Photonics News a few years back.
I agree, this is a nifty item to have on your desk as Gee-Whiz Sciency Thing, although it takes up a bit of space. And it can get scratched up easily.
Sounds like you have a south-facing window. You could get a small telescope with a solar filter, like this. It’s enough to see sunspots. (Though we’re pretty close to solar minimum right now, so there isn’t always a sunspot to be seen.)
I’ve always liked Galileo thermometers but I suppose you won’t see much movement in an air-conditioned office.
I like those, but it’s so common to see the wrong explanation for how it works. As noted in the wiki article, it doesn’t work by radiation pressure. As I understand: the black side absorbs light/IR and gets warmer, which warms up the surrounding gas molecules, causing them to hit the black side harder. Measuring radiation pressure (photon pressure) takes a much more sensitive instrument.
Another idea: two linear polarizing filters mounted at a 90 degree angle, so the pair is opaque. Insert another polarizer or a retarder at a 45-degree angle, and it becomes clear.
That’s closer than the radiation pressure explanation but is actually still not correct. Radiation pressure would cause it to spin in the opposite direction than it actually does, so that’s easily refuted. The “hot side causing localized heating which increases pressure” explanation doesn’t quite work because the hot gas would expand in all directions, pushing away some of the molecules which would otherwise impact the vanes. That mostly cancels out the effect of hotter gas imparting more energy to the vanes. The actual explanation is a subtle effect called thermal transpiration, which occurs only along the edges of the vanes. The wiki article explains it.
Thank you for the correction. I should have read the cites in the Wikipedia article.
One more suggestion to the OP: the impossible nail through wood. You don’t have to make it yourself, you can just buy one. I’ve seen a room full of rocket scientists get stumped trying to guess how it was made.
Other flexagons can be made, but they’re more complicated.
Decades ago, I had a kit called “Kaleidocycles” to make flexahedrons from regular solids, decorated with Escher graphics! Sadly, it’s long out of print.
Somebody uploaded the “Kaleidocycles” book to archive.org! (This is probably a copyright violation, so I’m not giving the direct link.) MAYBE it includes the plans for the objects, so you could just print them, cut them out and construct them.
On the life-sciences side, many butterfly caterpillars are quite easy to rear and take up very little space, and are wicked cool to watch especially when forming a chrysalis or “eclosing” (becoming byutiful butterfly).
Actually, even the commonly-given “correct” answer to how the radiometer works isn’t really correct. The actual reason the things turns is a rather subtle variation on the “heating up the residual gas molecules” reason. If that were all there was to it, two different effects would cancel each other out. The rotor turns because of edge effects at the edges of the vanes. (see point #4 in the “explanations” section on the Wikipedia page – Crookes radiometer - Wikipedia )
William Crookes, who designed and built the device, was convinced that it measured radiation pressure (Crookes was a great designer of demonstration apparatus, and his devices are still used today. But he held no academic post and ran his own private laboratory. He investigated new phenomena, but didn’t always understand it. ) His compatriots pointed out the problems with his interpretation of the operation of the radiometer. An interesting guy, who made a big splash. But in his later years he became obsessed with spiritualism and was taken in by some accomplished tricksters in the field.