Archive for April, 2012

Relativity Goes to the Dogs

This is late, and I have to apologize for that, but I finally got to finish reading Chad Orzel’s How To Teach Relativity To Your Dog. For my tardiness I blame the really nice stretch of weekend weather we’ve had, which “forced” me to do outdoorsy things with my disposable free time. (There’s also the issue of my bifocals, which make reading small-ish type somewhat uncomfortable, or I might have finished this one or two sittings)

Chad is a professor at Union College in Schenectady, NY (something I can type without looking it up, since I grew up in that area), has a background in atomic physics and writes a blog called Uncertain Principles. If you read my blog on a regular basis you should already know of him, since I link to his blog on a fairly regular basis.

I’ll get this part out of the way first: I am not a data point to confirm that this will help you understand relativity; I’m not really the target audience — I already have an understanding of relativity. I was happy to be offered a copy of the book for review, but I don’t normally buy mass-appeal (or books that aspire to be mass-appeal) physics books, because I already have a physics degree. But I can say this: I think it’s a valid approach, and it’s done fairly well.

The problem with mere textbooks is that they are usually quite dry, and pop-sci books often skimp on technical accuracy in trying to compensate to engage the reader. Chad has grabbed the middle ground in using the conversations with his German shepherd, Emmy (The Queen of Niskayuna) to both set up the discussions and to raise objections to the various conundrums that appear in learning about relativity. The dialogue format is helpful, because as anyone familiar with the topic knows, there are a lot of moments in learning relativity where the natural reactions is, “Whoa! That doesn’t make sense!” and this is pretty much what happens. (The only textbook I’ve read that uses a conversational approach is Electrodynamics by Griffiths, which is excellent) There’s a lot of dog dialogue (dogalogue?), and depending on your tolerance for the approach (along with some puns and pop-culture references) it might be a little much. There’s 300 pages of it.

Chad covers all the topics, starting with special relativity, including spacetime diagrams. Invariant quantities and E=mc^2 follow, and then general relativity, with all that entails, along with the ramifications of relativity in the form of cosmology and high-energy/particle physics.

The diagrams and equations are a necessary evil, but shouldn’t scare you off if you find them intimidating, because there’s plenty of discussion, and no problems to work. The satisfying part for me was that the level of technical accuracy is quite good (which is not at all surprising) even at the level where it probably wouldn’t matter to the casual reader, but things I would pick up on, especially in discussing clocks. In fact, I think my only technical nit was when he discusses energy holding nuclei together (forces hold things together) but in the context of the depth of the discussion, I understand the approach.

All in all, a pretty good book, and something a science enthusiast would probably find to be a worthwhile read.

"Buckeyball" Motor

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These “Buckeyball” magnets look like fun (but IMO a tad pricey for a good-sized collection). The towers are just for structural integrity; it’s the ones on the battery itself that are responsible for the motor action.

A Beaker of Tea, Perhaps?

Chemicus service set

Chemicus is a service set for Russian chemists/patriots; made of fine ceramics and adorned with a traditional Gzhel pattern, it repurposes laboratory test tubes and beakers for home-kitchen experiments.

Interesting that the kettle and vase have a biohazard symbol on them.

Are Forts Your Forte?

And the Walls Came Tumbling Down, Again

“We also get to talk about tension and compression,” he said, though he avoids technical terms. “We talk about pushing and pulling.”

His big innovation is using blankets to wrap two large cushions so that they create a large wall panel that can stand on its edge. In fact, he creates several such panels. Then he uses another blanket or sheet to attach adjoining panels, in effect connecting the walls of the fort.

More Fun Than Plato's Coaster

Physics demonstrations: the Pythagoras cup

This is the trick of the Pythagorus cup, also known as the Pythagorean cup or the Tantalus cup! It can be used as a nice prank to play on someone (don’t use red wine, unless you need to replace your carpeting anyway), but also serves as a nice demonstration of some physics of fluids.

Don't Use Duct Tape for This; it Tastes Terrible

The Food Lab: My Favorite Cooking Hacks

I already covered their beer-cooler sous-vide hack. For the wok hack,

When filled part way with coals and allowed to ignite, the well-ventilated chimney channels all of that heat energy upwards.

True for the convection, which is the most important heat transfer going on. (But the radiation is still pedantically being emitted out the other sides.) And the ice-cream-without-an-ice-cream-maker sounds intriguing. I’ve had liquid nitrogen ice cream, which is a truly geeky hack that achieves the same goal of quick freezing so you get small crystals.

via @rjallain (via @seriouseats)

Flipping Out

Flying object propels itself by flipping inside out

The design is based on the inverted cube shape discovered by inventor and mathematician Paul Schatz. By dissecting a cube into three parts, two star-shaped units can be produced at either end with an invertible belt in the middle section which is the same shape as the flying band. The system reproduces the entire structure: it opens to release the band while the ends remain on the ground as a docking station.

The video seems odd, though — it looks like they speed it up in spots, making it more difficult to tell what’s actually going on.

Mostly Correct

xkcd: Approximations

Monkey Launching Capability

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First place I saw this didn’t mention what the combustion reaction was, but via kottke:

If you mix calcium carbide and water, it produces acetylene. Acetylene is extremely flammable and can launch 55-gallon drums into the air when ignited.

Yosemite Range of Light Time-Lapse

Yosemite Range of Light

Yosemite National Park, the High Sierra, and the Eastern Sierra are some of the most beautiful places on earth. Ever since I serendipitously won a trip to Yosemite when I was 18, the beautiful Range of Light has captured my heart and become my home. Nothing brings me more joy than to share this life changing beauty with others.

Ever since I became fascinated with timelapse photography almost 2 years ago, after seeing the work of Tom Lowe, I’ve wanted to do a piece on Yosemite and the Sierra. Now after almost 2 years of shooting, I’m thrilled to share. I hope you enjoy my vision of my home, the majestic Yosemite & Sierra. Best viewed Full Screen with Sound 🙂

There’s a neat effect about halfway in, with the spray from waterfalls making a rainbow, but since it’s time-lapse, you can see the rainbow move as the sun’s position changes.

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