I’ve talked in some detail before about the Kaye effect, in which a shear-thinning fluid such as shampoo or liquid soap can be made to “bounce.” Well, I did one final experiment with the Kaye effect, in order to show that the shampoo can be used as a light guide, as was demonstrated in 2006 by a Dutch research group.
My video result is posted below: nearly 3 glorious minutes of a cascading stream of shampoo with light glowing from within! I was never able to get a truly stable Kaye stream, but the effect is almost more fun with the stream erratically bouncing.
I hereby declare that the 59th edition of The Giant’s Shoulders, the history of science blog carnival, is up at Something by Virtue of Nothing! This edition, centered around the theme of the Antikythera Mechanism, includes posts about:
- Did Isaac Newton slash the portrait of Robert Hooke?
- The Haunt of the Resurrection Men!
- Views of the dangers of masturbation for women,
- The weirdest weapons of history,
- and much more!
Many thanks to the hosts for an excellent carnival! The next edition, the five-year anniversary of the carnival (has it really been that long?), will be hosted by The Renaissance Mathematicus. As always, submissions can be sent to me, ThonyC, or the host blog — the latter two of which are the same this time!
Do not all charms fly
At the mere touch of cold philosophy?
There was an awful rainbow once in heaven:
We know her woof, her texture; she is given
In the dull catalogue of common things.
Philosophy will clip an Angel’s wings,
Conquer all mysteries by rule and line,
Empty the haunted air, and gnomèd mine—
Unweave a rainbow, as it erewhile made
The tender-person’d Lamia melt into a shade.
-John Keats, Lamia (1820)
Poet John Keats (1795-1821) once famously — and infamously — joked that Isaac Newton had destroyed the poetry of the rainbow by “reducing it to the prismatic colors.” This statement has been quoted often whenever someone wants to argue that scientific knowledge dulls the beauty and poetry of nature.
Keats was being an idiot, though: a true understanding of the science behind a phenomenon only adds to its beauty. There are so many subtle aspects to even the simple optics of a rainbow that make it a fascinating and lovely subject of contemplation. Once you get past the basic science of a rainbow, you are well-prepared to study more sophisticated and unusual phenomena such as this double rainbow that my wife and I saw from our house last July.
I’ve had rainbows on my mind since I was recently asked to explain some of the optics by a journalist. Surprisingly, standard optics textbooks such as Born and Wolf’s Principles of Optics and Hecht’s Optics have no discussion of the phenomenon. This is likely due to the fact that most optical scientists have no need to understand rainbows in their research, but this does not mean they are not objects worthy of study.
So let me endeavor to explain all about rainbows: how they form, how double rainbows form, when fully circular rainbows form, and anything else I can think of. This isn’t just trivia: a lack of knowledge of rainbows can lead to truly humiliating consequences.
This post continues a long-neglected series of posts about classic novels of science fiction and horror that were adapted into movies of the 1950s and 1960s. Years past, I talked about John Wyndham’s The Midwich Cuckoos and The Day of the Triffids, as well as John W. Campbell’s Who Goes There? In this post I consider an equally iconic novel that was adapted into four movies so far, and likely more to follow!
The 1950s and 1960s must have been a wonderful time to be a science fiction writer. Not only was the genre at the height of its popularity, but its novels were readily tapped for screen adaptations. Growing up, I was completely unaware that many of the films I watched on Sunday afternoon “Creature Features” were based on novels, but now I find it fascinating to go back and see how the movies compare to their original inspirations.
One of these that I believe almost everyone on the planet must have heard of at one point or another is Jack Finney’s The Body Snatchers (1955), later revised to Invasion of the Body Snatchers.
First edition cover via Wikipedia, which actually accurately depicts a scene in the book.
Finney’s book was an immediate sensation, and was quickly turned into the instant classic 1956 film Invasion of the Body Snatchers. Three other adaptations followed, in 1978, 1993 and 2007. But what of the original novel, and how does it compare to the films? Let’s take a look!
A good demonstration of a physical phenomenon should be both insightful and exciting. Sometimes, a demonstration succeeds at both so well that it is practically awe-inspiring. Such is the case, for me, with the demonstration of Chladni patterns, exotic and beautiful vibration figures that can be displayed with the help of just a little sand.
The demonstration of a couple of Chladni patterns are shown in the video below. A metal plate, supported by a post in its center, is vibrated at a single frequency by use of a mechanical driver. For most frequencies, nothing at all happens; when certain special frequencies are hit, however, standing waves appear on the plate, driving the sand away from the points of large vibration to the points of no vibration. By varying the frequency of oscillation, we can find a large number of the so-called resonance frequencies and their accompanying patterns, which become increasingly complex and beautiful as we up the rate of oscillation.
Chladni figures are a lovely examples of resonance, an important concept in almost all branches of physics, including vibration. Rigid and semi-rigid bodies possess an (in principle) infinite number of natural frequencies of vibration at which the object “wants” to move. In this post we look at resonance, as illustrated by Chladni’s demonstration, and the role it plays in numerous phenomena.
I’ve spent a lot of time on this blog talking about the optics of invisibility, both hypothetical and actual. Though a number of forms of invisibility have been considered in both science and fiction for over a hundred years, the study of the subject really exploded in 2006 with the publication of two theoretical papers introducing designs for “invisibility cloaks.”
The principle behind one of these cloaks is illustrated below, taken from the original paper by Pendry, Schurig and Smith. The cloak guides light around the central region and sending it along its original path, like water flowing around a boulder in a stream. The lines in the illustration represent rays of light being deflected and returned to their original trajectories.
The device is passive; it “works its magic” by virtue of the materials it is built out of, and guides light around the hidden region by what amounts to refraction.
It is fun to talk about the unusual implications of optical invisibility, but it is hard to show it! Cloaks are complicated, and there are relatively few experimental realizations to date — and those that do exist are not easily reproducible without a lot of resources.
Fortunately, there exists a simple trick, suggested by my colleagues*, that can be used to demonstrate the principle of cloaking in a striking way! I assembled a version of this trick myself for use in a recent popular talk on invisibility physics that I gave; a short video of it is shown below.
A finger placed behind the device is readily visible, but a finger placed within the cloak vanishes!
For about $50, you too can make your own “cloaking device”, albeit an oversimplified and crude one! Let’s take a look at how it is done.