This morning I read an essay on Pharyngula by the popular blogger and prominent atheist PZ Myers. Someone sent him photos of a funny shaped rock and asked him for his interpretation. This reminded me of an episode that occurred to me some years ago.
First off, some background. Some years ago I interacted online with a man named Anton Wroblewski. At the time we were both interested in elements of the Bigfoot issue. Dr. Wroblewski is perhaps best known as the individual who analyzed the Skookum body impression as that of an elk. As you can see by his CV, he has a PhD in geology as well as masters in stratigraphy and vertebrate paleontology.
I finally met Dr. Wroblewski in March of 2010 when he visited Seattle.
It’s great to know people with genuine expertise, as you can ask them questions! Some years back I had been walking along Alki Beach here in Seattle. I started noticing funny shaped rocks, or perhaps teeth, in the sand. I picked a few up. Since my educational background is a BS in pharmacy, I really didn’t know what I was looking at. Were they rocks? Were they fossils? Were they eroded teeth? Why did they have little pits? I’ve always been a curious person so I decided to follow up on what I found. I sent Anton a photograph of the specimens. He thought they were intriguing, but wouldn’t speculate further without examining them. I packaged up the strange samples and sent them off. He examined them and suggested they were not fossilized shark teeth as I had fantasized, but simply funny looking eroded rocks. Well, no harm no foul.
I was appalled to see how differently PZ Myers chose to react to someone who sent him photos of a strange rock sample:
“He also sent me these photos in much higher resolution. Why? Because he’s an ignorant nudnik. These things look nothing like the brain of any creature that has ever existed, unless maybe it’s the lopsided lumpy non-functional excrescence found inside the crania of creationists.”
I’m sure that a celebrity such as Myers is often the target of cranks that send all sorts of things. Yet how do we know that this individual was an “ignorant nudnik” or a legitimately curious person?
It’s doubly disturbing to consider that Myers is an instructor at the university level. Does he behave like this to his students? There is already an enormous social pressure in classrooms against asking questions. No one wants to look foolish by asking a “dumb” question. You can see this social pressure in action when people add meta-data to their questions with the preface “this may be a dumb question but…”
There are excellent resources on the Internet for those without personal access to PhDs. One that comes to mind is AskMeFi or Ask Metafilter. One of the things that keeps a resource like that functioning is close moderation. Personal attacks like asserting the questioner is an “ignorant nudkik” are not tolerated. I’ve used AskMeFi to help me gather information about such strange things as “Mountain Marbles.” For those who are particularly wary of publicity, it’s possible to ask questions anonymously.
While it’s perfectly reasonable to dismiss those questions that are not asked in good faith, it’s unfortunate to see mockery and dismissal used by someone like Myers who should know better. Of all people, Myers should be well aware of how much pain and misery in the world is caused by ignorance. Inherent in asking a question, ANY question, is the admission of ignorance. When the very act of admission of ignorance is mocked, as Myers is doing, it creates a chilling effect for those who might wish to learn.
POSTSCRIPT:
While out exercising today, it occurred to me the individual who sent the photos may have not specifically ASKED Myers what the rocks were. Upon carefully re-reading the post, it appears that the individual concluded that the inorganic sample was “mineralized brain.” Heck, I can relate, I thought I might have found “fossilized shark teeth.” Without specific clarification, we can’t know what exactly the individual claimed.
Easy, just beam up from the Halkan planet during an ion storm and come aboard the “mirror” Enterprise!
Actually there is another way that really works, but the real message here is about examining things that we take for granted during our day-to-day lives. First off, what makes a pair of scissors “handed” in the first place? It’s more than just a molded handle that fits comfortably into a right hand or a left hand. It has to do with the topology of the shears so that they are held together during closing.
Consider how your right hand closes when you cut with a pair of scissors. The handles apply force across a revolute joint which acts as the fulcrum for two levers. But there is more going on than just a simple up and down movement, and this is the key to “handedness.” Your hand is applying a torque or slight twisting force across the fulcrum which helps keep the shears held together. Where does this torque come from? It’s part of the movement your hand makes as you close the scissors.
A pair of scissors is held between the thumb and the fingers when cutting. When the scissors are fully closed the thumb is on the outside of the fingers. Thus the hand is essentially forming a fist, the most fundamental motion of a hand with an opposed thumb.
Imagine a small rod held between the inside of the thumb and the outside of the fingers as you make a fist with your right hand. Which way would it rotate? With a little bit of visualization you can see it would rotate clockwise, as seen from above.
Conversely, the same rod held in the same position of a left hand would rotate anticlockwise, as seen from above.
Now we get to the secret. Notice I qualified the assertion about the rotations with “as seen from above?” That’s because if we see a rotation from the other end, or from below, it is seen to rotate in the opposite direction. Besides the shape of the handles, a right handed scissors is designed for a clockwise torque and a left handed scissors is designed for a counterclockwise torque, as seen from above.
Instead of beaming into the mirror universe of Star Trek, we can “see from below” by turning the shears around! When right handed scissors are held normally in a right hand, the applied torque is clockwise as seen from the revolute joint. When held with the blades facing backwards in the right hand the torque is applied counterclockwise as seen from the revolute joint. The best way to understand these issues is to simply hold a pair of scissors in your hand and feel for yourself the forces involved. Holding a pair of shears backwards is totally goofy for practical purposes, but the goal here is to illustrate what’s really going on.
I purchased several books while I was at TAM 9 in Las Vegas, one of which was Daniel Loxton’s recent book Evolution. Ostensibly written for kids, it’s a winner both for its accessible scientific content and its artistic merit. I finished reading the book thinking how much anguish I could have avoided if I were exposed to a book like this when I was about 15!
The scientific concepts are explained simply and fundamentally. On page 17 the process of natural selection is broken down into just three simple steps. Because the fundamental principals are so powerful and encompassing the explanatory power is enormous. Loxton uses straight exposition as well as question and answer to explain the phenomena that result from the simple principles of natural selection. Much to the book’s credit, a number of these questions directly address classic creationist arguments against evolution. Loxton devotes two pages to the question “how could evolution produce something as complicated as my eyes?” I found this particularly moving, as I had been exposed to creationist literature as a child that raised this same point. Oh, to have had this book as a youth! Not content to simply give an abstract rebuttal, Loxton provides two examples of creatures that have functional “eyes” with lower structural complexity than human eyes. One is the chambered nautilus, which I was not familiar with even as scientifically literate adult.
I had the benefit of speaking to Daniel at the meeting after I had read his book. Indeed, he told me that he often writes for kids in such a way as to provide resources that he wished he had as a youth. I suspect that many young people who read this book will have been exposed to creationist concepts, so it’s entirely appropriate that the perennial arguments are addressed.
This book is also an artistic triumph. There are multiple forms of illustration, including landscape photography, conventional illustration, digital illustration, and photographed sculptures. Clearly an illustrated book on evolution should include depictions of extinct species, often extinct for millions of years. In most cases Loxton created a digital illustration and composited it into a photographed background. This techniques has multiple risks, all of which Loxton has overcome. First off, the animals must be believable, both in gross morphology and surface texture. On both counts the illustrations work. The fine skin detail on the stubby-legged creatures on page 31 is stunning. Even the convoluted textures on the foreground plants are outstanding. I spoke to Daniel about this specific issue and indeed he devoted a great deal of effort into producing believable textures.
Most of the digitally created animals are composited into landscape photographs. Artistically this runs the risk of looking like a typical Hollywood CGI action movie. To look realistic, a composited scene must have a single focal plane, as that matches how the human eye works. All too often in shoddy CGI images both the foreground image and the background plane are in perfect focus. Thankfully Loxton chose to have his foreground animals in focus and his backgrounds correctly out of focus. His composited images also exhibit correct aerial perspective with regards to luminosity and detail.
The conventional illustrations are obviously quicker studies. Loxton has a unique drawing style in which his lines are particularly bold. Despite this his illustrations are able to convey a surprising depth of subtlety, as in his illustration of a woman on page 44. Though it’s a small drawing, there is a hint of epicanthic folds in eyes of the figure. At points, though, the luck runs out, as on page 15 where the outlines of a boy’s hands are so thick it’s slightly distracting.
Not content with a two dimensional triumph, Loxton exhibits his skill as a sculptor on page 32. A hominid’s head is shown with strong lateral lighting. Loxton used a Crayola sculpting compound for a resounding success. There is some digital post processing occurring in this image, and if I recall correctly the eyes were digitally composited in. Once again, Loxton’s attention to surface detail is seen in the bust, as well as his own self confidence in his creation to allow it to be seen in a strongly lit close up.
All in all, this book is a winner. It explains a powerful scientific theory in elegantly simple ways. It touches on creationist arguments without being contentious. The illustrations are superbly integrated with the text, and are an artistic triumph. This book needs to be in every school library.
Update: Some time after this review was written, Loxton’s book generated some controversy but went on to win a literary award.
I think I first encountered the term “thixotrope” in conjunction with epoxy and the additives you can mix it with. I remember reading about fumed silica, and was amazed that such a product could be created and sold commercially that was so small in particle size. I’ve worked with fumed silica, and indeed it is an amazing substance.
I suspect that other people might conceptualize the property of thixotropy much like I did, and imagine that it’s a property of a material. But if you look at the definition of thixotropy, at least that given by Wikipedia, you notice that it’s a property of “certain gels or fluids.” What got me thinking about this is that a material can become more or less thixotropic depending on its physical state.
I remember sitting at a Mexican restaurant in LA with some of my cousins back in the summer of 1984 and one of my cousins was pouring a carafe of frozen margarita mixture into a glass. He tipped the carafe higher and higher, but the icy mixture still wouldn’t flow. All of a sudden the mixture started flowing catastrophically, at least as far as the glass and table was concerned… One of my other cousins remarked something to the effect that “he wondered if that was going to happen.”
If I understand the concept of thixotropy correctly, then I believe that water is a sort of “auto-thixotrope” in that it’s a material that can become thixotropic depending on its physical state. A fine grained ice slush, like that in a Slurpee or a margarita, exhibits thixotropy. Neither ice nor water by itself is thixotropic, yet a mixture of the two is.
Perhaps I should qualify the last concept, as when I think about it, I suppose that a block of ice would behave differently physically than the same mass of ice broken up into cubes. Perhaps snow is thixotropic, as I think an avalanche might qualify as an example. So now I have to wonder if particle size, particle shape and temperature are factors as well. With water, or more accurately snow or ice, you have further complications conceptualizing this, as you have the molecular lattice structure on the microscopic scale, as well as the “particle” size and shape on the macroscopic scale. The drink in your hand behaves differently as a material depending on the size and shape of the ice “particles” inside. A Slurppe pours differently than Kool-Aid with ice cubes.
So it makes more sense to me how the definition of “thixotrope” is constructed broadly, to encompass “certain gels or fluids” and not strictly as a property of a material. There is a lot more going on than one simple physical property.
I remember a physics class in college where I was introduced to the fact that there was an entire branch of materials science known as “rheology.” At the time I was amazed that an entire branch of science could be devoted to such an esoteric thing as fluid flow. Now it makes more sense, as I can begin see how complex it really is!
Most consumer grade laser pointers come with a momentary switch. Some people might want to have a conventional on/off switch instead, say for photography. Here’s a quick and easy modification that requires no switch replacement or re-wiring.
Start by wrapping tape around the barrel of the pointer right next to the button switch. Build up the tape to a height of about one millimeter. Don’t wrap with a lot of tension, or you may experience the dreaded “tape creep.” Wrap two bands which will act as retainers to keep the modified switch from sliding up or down the barrel.
Find a zip tie that’s roughly the same width as the momentary switch button. The zip tie I’m using is about 5mm wide. If you use a wider zip tie, your tape retaining bands will have to be moved aside to the same width as the zip tie. Encircle the zip tie over the barrel in between the tape retaining bands. Contract the zip tie until you come near the button, positioning the zip tie locking lug over the button. As the zip tie contracts, it will form a teardrop shape, with the locking lug forming the pointed end. Carefully contract the ratchets of the zip tie until the lug almost touches the button but does not turn it on. This is the new “off” position, and should look like this:
Rotating the tie will remove the slack under the locking lug and depress the momentary switch. This is the new “on” position, and looks like this:
Cut off the excess “tail” of the zip tie, and you now have a reasonably elegant on/off switch.
I was able to use my modified laser to capture this image, which is a green glass sculpture in Seward Park here in Seattle:
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