Since we got some great news the other day, a happiness-filled Because it's Friday post is a must this week. This Pomplamoose remix of Pharrell William's Happy with Daft Punk's Get Lucky — featuring very clever use of a standard "beamer" video projector for the visual effects — fits the bill nicely.
In the video below from The Atlantic, the differences in the way US citizens describe or pronounce various things is illustrated in a series of phone calls (via Sullivan):
If you're wondering how your dialect fits in, you can try the New York Times Dialect Quiz. Answer 25 questions, and it will identify the 3 US cities that most closely match your dialect. I'm not a native US English speaker (I grew up in Australia, and spent many years in the UK before moving to the US West Coast in 2000), so I basically flunked the quiz. My words for a freshwater crayfish ("yabbie") or that area of grass by the road ("nature strip") weren't on the list, and so I got placed somewhere in southern Florida (which I guess is at least as far South as you can go!). Judging from the responses from some of my friends on Facebook, though, the quiz can be uncannily accurate if you were brought up in the US.
Available in pink (log-Normal distribution), yellow (chi-square distribution), light green (Normal distribution), baby blue (T-distribution), and lilac (uniform distribution). They're cute, they're educational, last longer than roses and much better for you for chocolates — and the patterns were created with R.
Have fun this Valentine's Day, and we'll be back on Monday.
You can see a couple of other clips here, here and here, and the entire film is playing at planetariums around the world. Which gives me something to do this weekend! Hope you enjoy yours — we'll be back on Monday.
The basic principle is fairly straightforward: pairs of speakers generate a standing wave (at ultrasonic frequencies) at a focus point, and the motion of the air molecules is enough to keep the particles suspended. With some clever engineering, by varying the phase of the sounds, the can move the focus point (and also the particles). Sadly, it's had to see how this could be scaled up to macro-sized objects though.
That's all for this week! See you back here on the blog on Monday.
In 2012, filmmakers Sophie and Liberty took a canoe trip on the Shannon River in Ireland. You can see their approach to a fog-enshrouded island in the still frames at the start of this video, and then they encountered sometime breathtaking in motion:
(Via Vimeo Staff Picks.) It still amazes me that simple rules of individual agents (all one bird knows is to avoid predators and not collide with other birds) can create such complex (and beautiful) emergent behaviour. On a similar note, tracing the paths of indvidual birds create their own distinct patterns:
(via FlowingData). We'll be back on Monday, but if you're out and about this weekend, take a closer look at the birds in flight. You might see them in a different light.
Zach King consistently manages to combine humour, surprise and magic into six-second vignettes on his Vine channel. Here's a compilation — it's 7 minutes total, but I bet you watch to the end.
It's not "magic" in the traditional sense of course, more like camera cuts combined with some deft editing in Final Cut Pro. But it's nonetheless impressive, and in just about every case the concept and execution are flawless. The Independent has a recent profile of Zach, which explains some of his tricks.
I was surprised that the illusion went viral, but on reflection it's easy to see why it was so popular. It really is mind-blowing: despite being told that the two blocks are the same shade of grey, your mind rejects the possibility until you actually compare the on-screen colors directly. Phil Plait's Bad Astronomy blog gives a great explanation of the illusion, and finds its original source: Purves Lab.
I had several people suggest via Twitter that this isn't really an illusion at all: in "real" life, those blocks are in fact, white and dark: it's just the shadow on the white block and the lighting on the dark block that make them the same shade in the on-screen representation, and this is obvious to anyone who's ever studied color theory. But I think this is exactly the point that makes the illusion so suprising: for anyone (like me) who hasn't studied color theory, it's a real suprise to find the disparity between what our brain interprets as color, and the frequency of light that enters our eyes. I certainly have a greater appreciation for the skill of artists in mixing paint to match a scene. (Check out this TEDx talk for more about color and illusions, which features the Purves illusion above, and also the surprising news that 10 percent of women have four color receptors, and can therefore see more colors than the rest of us who only have three.)
But what about that "shady" illusion that started this all off? I don't actually think the Cornsweet Illusion is the explanation here, as there doesn't seem to be any variation in lighting between the diamonds. Anyone got another explanation?
If, like me, you struggled to understand the Fourier Transformation when you first learned about it, this succinct one-sentence colour-coded explanation from Stuart Riffle probably comes several years too late:
Stuart provides a more detailed explanation here. This is the formula for the Discrete Formula Transform, which converts sampled signals (like a digital sound recording) into the frequency domain (what tones are represented in the sound, and at what energies?). It's the mathematical engine behind a lot of the technology you use today, including mp3 files, file compression, and even how your old AM radio stays in tune.
The daunting formula involves imaginary numbers and complex summations, but Stuart's idea is simple. Imagine an enormous speaker, mounted on a pole, playing a repeating sound. The speaker is so large, you can see the cone move back and forth with the sound. Mark a point on the cone, and now rotate the pole. Trace the point from an above-ground view, if the resulting squiggly curve is off-center, then there is frequency corresponding the pole's rotational frequency is represented in the sound. This animated illustration (click to see it in action) illustrates the process:
The upper signal is make up of three frequencies ("notes"), but only the bottom-right squiggle is generated by a rotational frequency matching one of the component frequencies of the signal.
By the way, no-one uses that formula to actually calculate the Discrete Fourier Transform — use the Fast Fourier Transform instead, as implemented by the fft function in R. As the name suggests, it's much faster.