Jul 192011

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.

 Posted by on 07/19/2011 Science 2 Responses »
Jul 182011

I’ve been in Las Vegas the last few days, taking in my first TAM. For those who don’t know, TAM stands for The Amazing Meeting, an annual conference put on by the James Randi Educational Foundation. This years meeting was “TAM 9 From Outer Space” with presentations having a space-based theme. One speaker was Bill “The Science Guy” Nye. I hadn’t seen Bill Nye in person in many years, and I thought his presentation was great. Funny and inspiring at the same time. His talk reminded me of a strange criticism I once heard.

Years ago I was watching a sideshow performer demonstrate an amazing new stunt that involved red hot metal. To get his steel red hot he had to use a small forge which ran on propane and air. This was back in the 1990’s, long before the Station Nightclub fire which killed 100 people. That fire pretty much put the kibosh on indoor performances that involved fire of any kind. This gentleman was going to walk on red hot steel, or so he said. As with any sideshow stunt that has any element of danger, the stunt must be hyped beforehand for maximum effect. The hype in this case took a strange turn, as the performer began to criticize Bill Nye.

Unfortunately I don’t know what Bill Nye said in the first place. Frankly I never caught his TV show, only his early work with Almost Live, a local TV comedy show based in Seattle. I suspect, but do not know that Nye probably offered the common “explanation” for fire walking, namely that it’s a matter of the low heat conductivity of the wood embers that fire walkers walk on. A classic analogy is that it’s possible to leave your hand in a hot oven as long as you don’t touch the hot metal. Both the air and the metal in the oven are at the same temperature, but the metal is a much better conductor of heat.

In any event, the sideshow performer suggested that Bill Nye was wrong, that it was possible to walk on hot steel without searing the skin. At this point we should consider the social nature of such a performance. The goal of a showman’s pitch is to create tension, to hype the act, and hopefully to leave a lasting impression in the minds of the audience members. It shouldn’t be intended as formal physics presentation! Consider that when an audience enjoys a comedian, a certain suspension of disbelief is in effect. We are OK with a comedian telling a story that may be complete fiction, as long as the punch line is funny. An audience accepts this kind of thing in a comedian that wouldn’t be accepted in a scientist. But was the criticism of the sideshow performer valid? Is the “official explanation” of firewalking wrong? Well, sort of…

As our sideshow performer kept his bally going, his steel slats began to glow red hot. Coupled with the roaring sound of the forge on stage it was an awesome psychological setup. Soon his slats were set into a frame on the floor. In what must have been no more than a second or two the act was over. Indeed, our brave performer had “walked” on the hot steel slats. Only he didn’t really walk so much as hop. And therein is the crux of this whole essay, namely that sometimes simple “explanations” for phenomena fall short, and that the true description is more complex. What our performer was effectively utilizing was a low exposure time. Had he actually “walked” on the hot slats he would have surely gotten burned.

This is not to take anything away from our performer! It was an outstanding stunt, one which I’d never seen before and one which I haven’t see other performers doing. But for our purposes, let’s take a closer look at the physics involved, and what we can learn from it. A good resource on the subject is the Wikipedia article on Thermal Conductivity. A key passage is this:

For general scientific use, thermal conductance is the quantity of heat that passes in unit time through a plate of particular area and thickness when its opposite faces differ in temperature by one kelvin.

Note the critical variable of “unit time.” If we lower the time of exposure to a heat source, we lower the quantity of heat that flows to that which is being heated. A commonplace demonstration of this is running fingers through a candle flame. If you keep your fingers moving you can avoid a burn. The variable of time is often missing in explanations of firewalking. Indeed, the stunt is firewalking, not “firestanding!” Walking provides a series of exposures to the heat instead of one continuous exposure.

It should also be pointed out that skeptics have done an excellent job of debunking the claim that some sort of special mental or “spiritual” state is required to walk on hot coals. Skeptics Ben Radford and Joe Nickell have both performed this feat, and neither needed “chi” powers or motivational seminars to do it. I was amused at Radford’s account of his own fire walk, as he had organized it as something of a house party affair!

I actually began to think about these issues many years ago, way back in high school. Sometime in the late 1970’s I recall reading in Scientific American magazine the suggestion that firewalking could be “explained” by the “Leidenfrost effect.” Indeed, suggestions are still being made that this is the correct explanation. In my opinion this makes no sense as an explanation for the simple reason that any putative hovering water droplets would quickly be smashed into the sole of the foot or the wood embers by the walker’s body weight!

There is a temptation to glom onto “explanations” of seemingly mysterious phenomena. It’s unsettling to witness things that we don’t understand or can’t explain. But when incorrect or incomplete explanations are offered, it can backfire. A classic example in UFOlogy is “swamp gas” which became a term of derision for UFO advocates. I think skeptics are entirely justified in calling out those who would charge money for staging fire walking demonstrations, especially when it’s couched in terms of nonsense like “chi” energy. Today practitioners of marshal arts would call chi “bullshido.”

I would like to suggest that we get our physics correct when we suggest what is really going on…

 Posted by on 07/18/2011 Pseudoscience Comments Off on Fire Hop With Me