The bones that make up the skeletons of animals and people are a marvel of engineering. As one materials scientist put it:1
…bone properties are a list of apparent contradictions, strong but not brittle, rigid but flexible, light-weight but solid enough to support tissues, mechanically strong but porous, stable but capable of remodeling, etc.
More than three years ago, I posted an article about research that helps to explain why bones are so strong. The calcium mineral that makes up a significant fraction of the bone, hydroxyapatite, is arranged in crystals that are only about three billionths of a meter long. If the crystals were much longer than that, the strength of the resulting bone tissue would be significantly lower. What restricts the size of the crystals? According to the previous research, the tiny crystals are surrounded by molecules of citrate. It was thought that the citrate latches onto the outside of the crystal, stopping it from growing.
Some very interesting new research from the University of Cambridge and the University College London indicates that this is, indeed, what happens. However, it also indicates that citrate does much more than simply restrict the size of the crystals. It also helps to produce a cushion that allows bones to flex rather than break when they are under stress.
As I wrote in my previous post, last week was a very busy week. It started off in North Carolina, where I spoke at a church, a bookstore, and two classes made up of homeschooled students. I then traveled to Greenville, South Carolina to speak at the Southeast Homeschool Convention. This is part of the Great Homeschool Conventions, and I am scheduled to speak at all of them this year. I did the same thing last year, but this year was different, because I now have new books to sell.
Last year, I just sat in an empty booth and waited for people to come to talk with me. It got to be a bit dull at times, because without something in the booth, most people passed right on by. Of course, I had several great conversations with people who specifically sought me out to talk with me, but there was a lot of “down time” in between those conversations. This year, my new publisher (Berean Builders) had a booth, so when I wasn’t speaking, I hung out there. The publisher had my new elementary series, but it also sells the books I wrote with my previous publisher, so people could come to that one booth to see all the books I have written over the years.
The attendance at the convention was great (up significantly from last year), and I got to speak with a lot of people, both after my speaking sessions and at my publisher’s booth. I did three solo talks this year: Recent News in Creation Science discusses some of the more recent scientific studies that confirm the predictions of young-earth creationism or falsify the predictions of evolution. The Bible: A Great Source of Modern Science discusses some of the scientific facts that were written in Scripture long before science figured them out. Finally, Teaching Elementary Science Using History as a Guide discusses the rationale behind my new elementary science series.
I also did two talks with Diana Waring, who not only has an excellent history curriculum but is also about to re-release a series called Experience History Through Music. This three-CD/book set allows you to hear some of the classic songs written during different parts of U.S. history and learn the history behind them. It is a delightful product that allows students to not only learn history, but experience it! It would be an excellent supplement to any study of U.S. History. The talks we did this year were I Didn’t See That Coming and Arguing to Learn. The former was about what to do when your young-adult children make decisions that are unexpected, and the latter is about how debating different points of view can be an effective learning tool.
Last week was really busy. That’s why I haven’t written a post since the 13th. It started with a trip to The Homeschool Gathering Place in Raleigh, North Carolina. That’s where the photo above was taken. The owners of the store, who have been a blessing to homeschoolers for the past 18 years, arranged for me to speak at a nearby church, Colonial Baptist. It was a huge church, and the homeschool group there is quite large, so the turnout was great.
After the event at the church, I went back to The Homeschool Gathering Place and gave a talk about teaching science using history as a guide. That’s how my new elementary science series is designed. The talk was much more intimate, by design, and it generated a lot of good discussion. I also got to talk with students while I was there, as the picture above shows.
In between these appearances, I got to spend some time with an old friend, who I call “Roxy.” I think I might be the only one who still calls her that. She and I grew up together, but she left Indiana, and the last time I had seen her was more than 10 years ago. We seem to have the beginnings of a mutual admiration society going. She kept telling me how proud she was of what I had accomplished over the years, and I kept telling her how impressed I was with her. She is a very talented dancer, and I always looked up to her as we were growing up. Today, she is a mother who has raised great young adults. She also teaches dance and history to groups of homeschooled students. I got to help her teach two of her classes (history, not dance!), and those young students are incredibly blessed to have her! She is changing lives, and I am proud to call her my friend.
In the 1880s, an Italian scientist named Angelo Mosso built a balance that tried to measure the net flow of blood in the body. A man was put on the balance and asked to clear his mind. The balance was then set so that it stayed horizontal. The man was then asked to read something, and invariably, the balance tilted towards the head, indicating that his brain got heavier. According to Mosso, when the man read a newspaper, the balance would tilt a bit, but when he read a page from a mathematics manual, the balance would tilt more. One man was asked to read a letter from an angry creditor, and it tipped the balance more than anything else!
These results led Mosso to conclude that when the brain is actively working, it gets more blood from the circulatory system. The more it has to work (to process difficult information or strong emotions), the more blood it gets. When I originally read about Mosso’s work years ago, it reminded me of Dr. Duncan MacDougall’s experiments in which he tried to weigh the soul. If you have never heard of Dr. MacDougall’s work, he tried to measure the weight of six terminally-ill patients at the moment they died. He then did the same procedure on dogs. He claimed that while the people lost weight when they died, the dogs did not. As a result, he claimed to have demonstrated that the human soul has weight.
Of course, there are all sorts of problems with Dr. MacDougall’s work, and when I read about Mosso’s work, I rashly put it in the same category. While I am more than willing to believe that the brain needs more nutrients when it is hard at work, I have a hard time believing that its blood flow patterns would be changed dramatically enough to be measured by a balance. Fortunately, other scientists weren’t so rash. Dr. David T. Field and Laura A. Inman decided to replicate Mosso’s experiments, and the results surprised me.
It is well known in the scientific literature that the computer models being used by the U.N.’s Intergovernmental Panel on Climate Change (IPCC) have done a miserable job in predicting the change that has occurred in global temperature over the past two decades. You can see that for yourself by looking at the graph shown above. The various lines that have no circles or squares on them are the results of the climate models used by the IPCC. Notice that no model comes close to lining up with the actual data (the squares and circles). Indeed, the later the date, the worse the models become when compared to the data.
A group of retired NASA scientists and engineers led by Dr. Harold H. Doiron, a mechanical engineer who is best known for his work on eliminating unstable vibrations in liquid propellant rockets, has decided that these models simply can’t be used to make rational decisions about earth’s future climate. As this group says:
We have concluded that the IPCC climate models are seriously flawed because they don’t agree very closely with measured empirical data. After a 35 year simulation the models over-predicted actual measured temperatures by factors of 200% to 750%. One could hardly expect them to predict with better accuracy 300 years into the future required for use in regulatory decisions.
So what are we to do? If we can’t properly model how the earth will respond to increased carbon dioxide concentrations, how can we estimate what the consequences will be if we do nothing to curb the activities that are filling earth’s atmosphere with excess carbon dioxide?
In this research team’s mind, the answer is to look at the actual data and develop an empirical estimate. After all, we have about 100 years of measured data when it comes to global temperature, and we have a few thousand years of data that can help us estimate how the earth’s temperature has changed over that timeframe. In addition, we have measurements and estimates for how the amount of carbon dioxide in earth’s atmosphere has changed over time. If we look at past correlations between carbon dioxide and temperature, perhaps they can tell us what future correlations will be.
I have to admit that I am surprised no one has used this approach before. Sure, climate scientists have studied the correlations between past global temperatures and past atmospheric carbon dioxide concentrations, but this is the first time of which I am aware that scientists (and engineers) have tried to use those correlations to make definitive predictions about the future.
Pacific salmon are fascinating to study, because their lifecycle is so interesting. They hatch in freshwater streams, at which point they are called alevin. Although they have hatched, they still have a yolk sac upon which they feed. Once they have absorbed the yolk sac, they are called fry, and they begin feeding on the plankton in the stream. They eventually mature into parr, which are also called fingerlings. After about 12-18 months in freshwater, they move to the brackish waters of estuaries, ecosystems where freshwater rivers meet the ocean. At this point, they are usually called smolts. After a few months, they venture out into the ocean, where they will spend several years growing.
The amazing part, of course, is that after spending several years in the ocean, they return to the same freshwater stream where they hatched to spawn another generation. From a scientific point of view, one of the most important questions you can ask about this lifecyle is, “After spending years in the ocean, how do the salmon know the way back to the freshwater stream in which they hatched?” It makes sense that while they are fry and parr, they get a good sense of the mix of chemicals that make up their “home stream,” but they obviously can’t follow that trail of chemicals from the ocean! So how do they get from the ocean to the correct estuary so that they can get back to the stream in which they hatched?
About a year ago, I discussed a study that gave a partial answer to that question. It showed that sockeye salmon use the earth’s magnetic field as a “map” that leads them to the proper estuary. The study suggested the salmon had other means of navigation at their disposal, but the magnetic field was a very important tool in the fish’s repertoire. How do the salmon acquire this map? In the previous study, it was suggested that the map is imprinted in the salmon’s brain as it is traveling from the estuary to the open ocean.
Well, the same research team has done a follow-up study, and they have decided that this suggestion is probably not correct. Instead, the real story is more complex and much more interesting!
Many people know that bacteria have developed resistance to popular antibiotics. Indeed, it is a big problem in medicine, and it has caused many health-care providers to call for doctors to prescribe antibiotics only when they are necessary. The Centers for Disease Control calls this “antibiotic stewardship” and thinks it will improve medical care throughout the country.1 I have written about antibiotic resistance before (see here and here), because some evolutionists try to cite it in support of the idea that novel, useful genes can be produced by evolutionary processes. Of course, the more we have studied the phenomenon, the more we have seen that this is just not the case.
There are essentially two ways that a bacterium develops resistance to an antibiotic. One way is to have a mutation that confers the resistance. For example, a bacterium can become resistant to streptomycin if a mutation causes a defect in the bacterium’s protein-making factory, which is called the ribosome. That defect keeps streptomycin from binding to the ribosome, which makes streptomycin ineffective against the bacterium. However, it also makes the ribosome significantly less efficient at its job.2 So in the end, rather than producing something novel (like a new gene that fights the antibiotic), the mutation just deteriorates a gene that already existed. While this is good for a bacterium in streptomycin, it doesn’t provide any evidence that novel, useful genes can be produced by evolutionary processes.
There is, however, a second way that a bacterium can develop resistance to an antibiotic: It can get genes that fight the antibiotic from another bacterium. Bacteria hold many genes on tiny, circular portions of their DNA called plasmids. Two bacteria can come together in a process called conjugation and exchange those plasmids, which allows bacteria to “swap” DNA. If a bacterium has a gene (or a set of genes) that allows it to resist an antibiotic, it can pass those genes to others in the population, ensuring their survival.
Of course, the natural question one must ask is, “Where did those antibiotic-resistance genes come from in the first place?” Many evolutionists want you to believe that evolution produced those genes in response to the development of antibiotics. After all, antibiotics didn’t exist until 1941, when penicillin was tested in animals and then people. Why would antibiotic-resistance genes exist before the antibiotics?