J.C. Moore Online

Current Events from a Science Perspective

In 1907 the deer population was unusually low with only 4,000 head. The carrying capacity was 30,000 at this time, so a massive campaign was waged against the natural enemies of the deer. Between the years of 1907 and 1923, the natural predators of deer (mountain lions, wolves and coyotes) were eliminated by hunters in order to increase the deer population. As the following graph shows rather dramatically, the deer population increased rapidly to 100,000 by 1924, but then died off rapidly to a mere 10,000 by 1939. Because of severe overgrazing by excessive populations of deer, the carrying capacity of this region was reduced to approximately 10,000 in 1939, and the deer population was reduced accordingly.

 

Deer Population on the Kaibab Plateau

The graph at the right shows what happened to the deer population during this period. When the carrying capacity of the environment is exceeded, natural populations do not reach an equilibrium point and stay there.The result is a massive die off, and the population is decreased below their original carrying capacity. The Earth has a carrying capacity for man, and though we are not exactly sure when we will reach it, it will undoubtedly be within this century. What will happen then?

(c) 2012 J.C. Moore

Would people be more likely to avoid unhealthy foods if they received a tax incentive to do so? A few countries think so, and have enacted laws to increase taxes on fat, sweet and salty foods. The outgoing conservative Danish government has passed a “ fat tax” on foods high in saturated fats. Hungary has also introduced a new tax popularly known as the “Hamburger Law” that involves higher taxes on soft drink, pastries, salty snacks and food flavorings.  

Denmark now has a life expectancy much lower than other surrounding countries. “Higher fees on sugar, fat and tobacco is an important step on the way toward a higher average life expectancy in Denmark,” health minister Jakob Axel Nielsen said, because “saturated fats can cause cardiovascular disease and cancer.”  The “fat tax” would help curb the country’s obesity problem and estimates are that it will increase the average life expectancy of Danes by three years over the next 10 years.

 Denmark’s and Hungary’s efforts to tax unhealthy foods might not be such a bad idea. While it seems that many people will not act to protect their own health, they might be a little more likely to eat healthy foods if they receive a financial incentive to do so. I doubt that the United States would ever have the political will to raise taxes on unhealthy food. We will just wait and pay the health costs. However, perhaps we could do it by lowering taxes.

Since many state legislatures have exhibited a passion for cutting taxes, they could encourage people to live longer and lead healthier lives by removing the sales tax on healthy foods. There are a number of resources such as Harvard’s Nutrition Source  that could provide the information that would be necessary to do that. Even without the financial incentive, it would be a good idea for everyone to become familiar with Nutrition Source, or even Dr. Oz’s list of 100 healthy foods.

(c) 2011 J.C. Moore

Research Credit: Barbara Moore

“Pictures of the polar region from 1979 and 2003 clearly show that about 30% of the Arctic  ice has melted. This has greatly affected the way of life of the native Inuit who live and hunt on the Polar ice.  While some may adapt, their way of life and culture, which sustained them for centuries, will be destroyed.”

Although arguments still rage about whether the Arctic sea ice is disappearing, the disappearance is a fact of life for those who live near the Arctic Ocean.   The photos clearly show that the Arctic Sea ice is disappearing. A recent TulsaWorld article described how the disappearance of the Arctic sea ice has affected the lives of the native Inuit people in Greenland. Ice which used to be 2 meters thick in the winter, now grows only a few centimeters thick, far too thin to allow dogsleds to go to the nearest town, 50 miles away across the bay. They can no longer venture onto the ice to hunt for seals or walrus, a mainstay of their diet,  nor can they go out on the ice to fish. The Polar bears they sometimes hunt have no fat, as the bears cannot swim to the ice packs to hunt, and they sometimes prowl the villages looking for food.

Drilling for oil has picked up in the area as the ices disappears, but so far little oil has been found. Exploration continues, and if oil is eventually found, it carries the possibility of  economic development. But it also carries  the possibility that an oil spill, almost impossible to clean up in the icy  environment, would destroy much of the ocean life the natives now depend on for food. The sad thing is that they are being forced to change a way of life that sustained them for centuries. While some may adapt, their way of life and culture will be destroyed, and many will likely end up among the poor and unemployed.

Note added on 03/22/ 2018: A recent article from the American Geophysical Union Journal EOS highlights the health risks to native Alaskans and describes the plight of the Inuit from climate change. Here are the words of one of their elders:

” Charles Sollie Hugo, a Native elder and oral historian with the North Slope Borough in Barrow, grew up hunting with his family. However, as the times when rivers freeze has shifted to later in the fall and their thawing has begun earlier in the spring, the window of time when it’s safe to traverse the land has narrowed, making caribou hunting less of a part of his life, he said.

Traditional permafrost cellars that Hugo once used to preserve meat have thawed, flooded, and become inaccessible.Traditional permafrost cellars that Hugo once used to preserve meat have thawed, flooded, and become inaccessible. “They are full of water right to the top,” he said. “They are no longer usable. They are contaminated because the permafrost is thawing out.”

(c) 2011 J.C. Moore

Aristotle thought that Nature could best be understood by observation and reason – and that all  knowledge should be open to examination and subject to reason.

Science Education has shown a renewed interest in Aristotle’s works. (1) Today, theories in science are often based on abstract and mathematical models of the world.  Students sometimes use the theories and equations without understanding how they were developed, their limitations, or even what problems they address. The development of an idea from Aristotle to the present would make physics more interesting and understandable. (2)  Aristotle’s works are reconstructions from fragmentary notes. He had the most rudimentary of scientific equipment, his measurements were not quantitative; and he considered only things that were observable with the eye. Ignoring these limitations has caused some to distort the significance of his work, sometimes to the point of considering Aristotle an impediment to the advancement of science. However, we should not project the framework of contemporary science on Aristotle’s work – but we should read his works and examine his Natural Philosophy in the context of his times. (3)

Scientific Method: In ancient times, events in Nature had been explained as the actions of the gods. The early Greek philosophers  questioned the role of the gods as the cause of events and by the fifth century B.C. the Greek philosophers, such as Socrates, had separated philosophy from theology. But, if the gods were not the cause of events, what was? Philosophers advanced explanations based on philosophical principles and mathematical forms. Aristotle found that unsatisfactory. He decided the principles of nature could be found within nature and could be discovered using careful observation and inductive reasoning. Observations must be capable of being observed by the senses and should include the four causes: the composition, the shape (or form), the motion (or change), and the end result (or purpose). Identifying the four causes insured a thorough understanding of the event. Chance or spontaneity were not considered causes. He thought all things in Nature should be open to examination and subject to reason – and he set about applying his methods to all knowledge.

Aristotle founded a school in Athens at the Lyceum which provided the world’s first comprehensive study of human knowledge from the perspective of natural philosophy. His lectures followed a pattern that formed the basis of the scientific method. They included a statement of the idea or problem, the precise definition of terms, a statement of what he and other scholars thought about the matter, the observations, arguments based on how well the ideas agreed with observation, and finally what could be concluded. His lectures notes are important as they not only show clearly his reasoning but they preserve many of the ideas of his contemporaries. (4, 5)

Physics: In his work,  Physics, (6) Aristotle examined the nature of matter, space, time, and motion. He had few tools for experimentation and could not measure time or speeds. He would not allow invisible forces so his reasoning did not include gravity. Things fell to Earth and the moon circled the Earth because that was their nature. He proved that infinite linear motion and voids could not exist on Earth. Without those, he could not escape the complexities of the real world or fully understand inertia. In spite of his limitations, Aristotle made some remarkable contributions to physics and laid the groundwork for Galileo, Newton, and Einstein. He reasoned that infinite velocities could not exist, that time and movement are continuous and inseparable, and that time was even flowing, infinite, and the same everywhere at once. These are all true and a part of Einstein’s Theory of Relativity. Some consider that Aristotle’s greatest contribution to physics was his description of time.

Reading Aristotle reminds one of reading Einstein. He takes the simplest of observations and in it discovers fundamental truths. Force is a push or a pull. A horse can pull a cart and the cart pulls back on the horse and when the horse stops, the cart stops.  Rest, then is the natural state of matter and the mover is acted on by that which it moves. These ideas became part of Newton’s Laws. He observed that there was both static and kinetic friction that opposed motion by studying shiphaulers. A hundred men could pull a ship but one man could not. Furthermore, he observed that the power needed to keep the ship moving depended on the force required and the speed. That is like the definition of power used today and, incidentally, something that Newton got wrong.  Aristotle examined objects falling in fluids and realized friction existed there also. He found that the speed of objects increased as the weight of the object and decreased with the thickness of the fluid. This is now a part of  Stoke’s Law  for an object falling at its terminal velocity. He also considered what would happen if the fluid became thinner and thinner but rejected the conclusion as that would lead to a vacuum and an infinite speed, both which he considered impossibilities. Galileo allowed those impossibilities and is credited with discovering kinematics.

Cosmology: We sometimes forget that Aristotle proved the Earth was a sphere. He observed that the shadow of the Earth on the moon during an eclipse was an arc. That was not conclusive as a disk might give the same shadow. The phases of the Moon and its appearance during eclipses show it to be a sphere and the Earth might be also. As one walks toward the horizon, the horizon falls away; and, as one walks North or South, different stars appear. These are as if one is looking out from a sphere. All things made of Earth fall to Earth in such a way as to be as near the Earth as possible. A sphere is the shape that allows this as it is the shape with the smallest surface for a given volume. All things considered, the Earth must be a sphere. Interestingly, an extension of that last argument is used today to explain the erosion of mountains, surface tension, the shape of droplets, and why the moons, planets, and stars are spheres.

Aristotle concluded that since all things fall toward the center of the Earth or move round the Earth, that the Earth must be the center of the Universe. The Moon and planets move around the Earth in circular orbits but must move in circles within circles to explain the variance observed in their orbits. The stars are fixed spheres that rotate around the Earth and the Universe must be finite else the stars at the outer edge would have to move at infinite speed. Aristotle was aware that if the heavenly bodies were made of matter, that they would fly off like a rock from a sling. He therefore added to the elements a fifth element, aether, to compose the heavenly bodies. Aether could not be observed on Earth but objects composed of it could move forever in circles without friction or flying away. (7) Perhaps Aristotle should have stopped with the moon, but the planets and stars were there and needed explaining. In spite of his model’s imperfections, Aristotle gave us a universe whose laws are invariant and capable of being discovered by observation and understood by reason. Aristotle’s model of the Universe lasted almost 20 centuries without significant modification and was so compelling that Renaissance philosophers and theologians built it into church doctrine.

Scientific Revolution: However, Aristotle’s model did not fit well with new observations made by 15^th century scientists. Copernicus realized that the planetary motions would be simpler and better explained if the Sun were the center of the universe. Tycho Brahe’s careful observations of planetary motions supported the Copernican model. Galileo used the first telescope to observe that Jupiter had moons that revolved around Jupiter and not the Earth. This was convincing evidence and Galileo championed a revision of Aristotle’s model. There was much resistance to the acceptance of the heliocentric model and Galileo was threatened with a charge of heresy for promoting the idea. Some people now consider Aristotle’s  ideas as an impediment to the advancement of science. However, the impediment was not Aristotle’s ideas – but that Aristotle’s model of the universe had become woven into the doctrine of the Church.

Galileo’s kinematics was also in conflict with Aristotle’s work. Galileo’s experiment with falling bodies is considered as one of the ten greatest experiments of all time. He showed that a small weight fell from the Tower of Pisa at the same rate as one ten times as heavy. This was considered by some to be a triumph of Galileo’s kinematics over the simple empiricism of Aristotle. That was not, however, the whole story. Aristotle had not only examined objects falling in air but also in liquids. He found that the rate of fall in liquids increased as the weight of the object and decreased with the thickness of the fluid. This idea is consistent with Stoke’s Law  for an object falling at its terminal velocity in fluids. Aristotle even had considered the case of a fluid with no thickness (a vacuum), but rejected the possibility since the speed would become infinite. However, Galileo’s experiment was performed in air and, while correct in a vacuum, Galileo’s mechanics were not exactly correct in air. Had Galileo dropped his objects from a much greater height, he would have found that the heavy object would reach the ground half again as fast as the small object. This is observable in hailstones where a large stone will strike the ground at almost twice the speed of a small stone. Galileo’s mechanics are only valid in a vacuum and even then would allow the velocity to eventually become infinite, which conflicts with Einstein’s relativity.  No one has thought to criticize Galileo for that.

Scientific Progress: Many thought, and still think, that Galileo’s work was the final overthrow of Aristotelian physics and the start of a revolution allowing science to advance. That is not the case. It is just the normal progress of science that models and theories are revised as better observations and understanding occur. The Revolution was not so much an overthrow of Aristotelian Physics as it was in moving from the observable to the imaginable – and in again separating science from theology and philosophy. It is ironic that Galileo was accused of heresy for questioning the theories of a man who thought everything should be open to question and reason.

(1)  ERIC. http://www.eric.ed.gov A search of the database shows 78 papers in the last three decades are about the use of Aristotle’s ideas in teaching.

(2)  Stinner, A. (1994). The Story of Force: from Aristotle to Einstein. Phys. Educ., 29, 77-85.

(3)  Lombardi, O. (1999). Aristotelian Physics in the Contest of Teaching Science: A Historical-Philosophical  Approach. Science and Education, 8, 217-239.

(4)  Durant, Will. The Story of Philosophy: The Lives and Opinions of the Great Philosophers of the Western  World. 5^th ed. New York: Simon and Schuster, 1949

(5)  Ross, W. D. Aristotle. 5^th ed. London: Methuen & Co. LTD. 1949

(6) Aristotle, Physics. Translated by R. P. Hardie and R. K. Gaye.
Provided by The Internet Classics Archive. Available at

    http://classics.mit.edu//Aristotle/physics.html

(7) Aristotle, On the Heavens. Translated by J. L. Stocks.
Provided by The Internet Classics Archive. Available at
    http://classics.mit.edu//Aristotle/heavens.html

Note: This article was originally written as the physical science
contribution to Aristotle's Enduring Contribution to Biology,
Physics,and Poetics by Surendra Singh, J.C. Moore, and Andrew Tadie.
It was published as Aristotle on Teaching Science  at the Seventh
International Conference on Teacher Education, New Delhi, India (2008)

The full article is available here.

(c) 2010 J.C. Moore

Fluoride is toxic at high levels but has health benefits  at low levels. Fluoride  is added to water at concentrations less than 1 ppm as it  helps to prevent tooth decay by hardening tooth enamel.  Tooth decay can allow bacteria to enter the bloodstream where they cause heart disease and other infections.  There are places where fluoride occurs naturally in water at ten times the concentration used to fluoridate water and there have been no long term effects except fluorosis, a brown stain on children’s teeth.

Fluoride is chemically about like chloride ion in the body – except that at high concentrations it forms a precipitate with calcium and ties it up. That’s the reason it is toxic at high levels. Fluoride can be used at fairly high doses to treat osteoporosis as it will keep calcium from leaving bones.  At 0.5 to 1 ppm, the amount usually used to fluoridate water, there have been no serious side effects. At above 1.5 ppm, fluorosis, a brown stain on the teeth may form in a few % of the population. There are places where natural sources of fluoride are as high as 10ppm and fluorosis is the only health effect found. Fluoride is toxic at high levels with an  LD50 of  125 ppm in rats and it is assumed to be about the same in humans. For comparison, the dose rate for aspirin is about 5 ppm  and the  LD₅₀ in rats is 200 ppm (1 ppm is 1 milligram per kilogram of body weight).

There are very few sources of fluoride in people’s diets except water or products where it is an additive. The source of the fluoride doesn’t really matter as most inorganic fluorides hydrolyze to form fluoride and bifluoride ion in water. Many toothpastes use stannous fluoride. Many countries add fluoride to salt or even to milk as tooth decay  is considered to be a much more serious health risk than fluoride exposure. The exposure from all sources should be kept below 1.0 pm so those who have fluoridate water or salt should not use other fluoridated products or toothpaste. If you are worried about fluoride in you water, there are water filters that remove it from drinking water and it is easy to avoid it from other sources.

Update, 3/14/2011: The U.S. Department of Health and Human Services is announcing a proposal to change the recommended fluoride level to 0.7 milligrams per liter of water. The standard since 1962 has been a range of 0.7 to 1.2 milligrams per liter. There was no health risk at the higher level, but fluorosis has been observed in kids teeth, particularly those who may get fluoride from other sources.

Update, 11/13/2012  Poor oral health, dental disease, and tooth pain can put kids at a serious disadvantage in school, according to a new Ostrow School of Dentistry of USC study. “The Impact of Oral Health on the Academic Performance of Disadvantaged Children,” appearing in the September 2012 issue of the American Journal of Public Health, found that  73 percent of disadvantaged kids in Los Angeles have dental caries, the disease responsible for cavities in teeth. Children who reported having recent tooth pain were four times more likely to have a low grade point average—below the median GPA of 2.8—when compared to children without oral pain. Poor oral health and dental problems also cause more absences from school for kids and more missed work for parents. Treating tooth decay is prohibitively expensive for some and tooth decay has been implicated in a number of later health problems, even heart disease.

Update, 04/11/ 2014: Some people are concerned, not about the toxicity of the fluoride, but of arsenic in the fluorosilic acid that is used to fluoridate most city water supplies. The fluorosilic acid from fertilizer manufacture, used to treat most water supplies, comes as a 20% solution and one source was analyzed to contain about 3.3 ppm of arsenic. By the time the solution is diluted to 1 ppm of fluoride, the concentration of arsenic is diluted to about 1 part per trillion. That is about 10,000 times less than the EPA standard for drinking water, which is 10 parts per billion (ppb) arsenic. It is difficult to see how that can be a health risk.

For perspective, some lakes near older coal-fired power plants have been found to have upward of 200 ppb of arsenic in the water. If I were concerned about arsenic in my city’s water supply, I would look at the concentration in the water from the lake, if that is the water source.

(C) 2010 J.C. Moore

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Personal styles reveal something about how we learn, think, and relate to the world.

Not long ago, National Public Radio reported that 29% of the US population was considered to be on the left politically. That is interesting as about 28% of the population is abstract /random, a description that is related to “personal style”. The study of personal styles usually includes thinking styles and learning styles. The studies are designed to improve education, self-awareness, relationships, mental health, and productivity. There seems to be little research available on whether personal styles are related to political views, but the possibility is interesting. Personal styles reveal something about how we learn, think, and relate to the world. Knowing a little about personal styles is a useful thing.

“Personal style” is a description of how we receive, store, and use information.  A simple, but useful, model for personal style was developed by Alexander Gregorc. (1) His model uses two perceptual qualities, “abstract” and “concrete”, and two organizational methods, “sequential” and “random”  (or “nonlinear” ) . Gregorc couples these to form four possible style categories: concrete/sequential (CS), abstract/sequential (AS), abstract/random (AR), and concrete/random (CR). Although everyone has all four qualities, most people are predisposed toward one or two of them. A survey found that about 51% of the population prefers CS, 28% AR, 13 % CR, and 8% prefer AS. These refer to a person’s dominant style. It is important to remember that everyone has some of each style and there is no “best style”. Still, personal styles can be fun and enlightening to investigate.

What’s Your  Style? A person’s dominate style can be related to preferred occupations, satisfying hobbies, and even things they might find difficult. An extensive description of all four styles is available at this link (2).  A simple, 15-question test can determine approximately a person’s style. It takes about 10 minutes and is at this link if you are interested. (3) Please note that these are very approximate categories that may change with time and that they may be situational. A person may prefer one style at work and another for leisure, such as a surgeon who is CS at work may much prefer AR type activities for hobbies.

Learning Styles: Although personal styles change with maturation, it is useful to consider that a student has a preferred learning style. Students with a CS style tend to prefer programmed instruction, workbooks, lab manuals, field trips, and applications while students with an AS style tend to prefer lectures, books, syllabi, and guided individual study. Students with a CR learning style prefer independent study, games, simulations, and problem solving, and students with an AR style usually prefer television, movies, assignments with reflection time, and group discussions. (2) There have been some efforts made to match teaching styles to student’s learning styles but it is impractical except in the largest of schools. Teachers are encouraged to be aware of the different learning styles and to use a variety of methods directed to each style. There is much more to know about personal learning styles and a good reference for that is Thelearningweb. (4)

Political Styles: Perhaps political discourse could be improved by a knowledge of personal styles. The most polarizing divide in politics lately had been between Conservatives and Liberals. A 2009 Gallup Poll survey found that 40% of Americans describe their political views as conservative, 35% as moderate, and 21% as liberal. (5) That’s not quite the same as the breakdown in the personal styles categories, but the similarity is interesting. From considering personal styles, we know that CS and AR dominant people perceive and organize information differently, that everyone has some of each style, and  that personal styles vary with the situation and maturation.  Rather than there being a big Liberal/Conservative divide, perhaps issues could be considered a personal style difference. Then, rather than calling each other elitists and ignoramuses, we could just say “That is certainly an abstract/random approach to the problem.” or “My, aren’t we being concrete/sequential today?”

(1) http://gregorc.com/gregorc.html

(2) http://www.floatingneutrinos.com/Message/arcs/links_on_abstractrandom.htm

(3)  http://www.thelearningweb.net/personalthink.html

(4) http://www.thelearningweb.net/learningstyles.html

(5) http://www.gallup.com/poll/120857/conservatives-single-largest-ideological-group.aspx

Scientific literacy cannot be measured by a litmus test such as belief in the Big Bang or evolution.

Every two years the National Science Foundation produces a report, Science and Engineering Indicators, which surveys the public’s attitudes toward science. (1) The report found for instance, that the public’s opinion of scientists ranks at the top of 23 other occupations and there is broad support for public funding of science research.  In spite of that, Dr. Lawrence Krauss, is unhappy because a section of the 2010 report about the public’s  science literacy was omitted.

In a Scientific American article, he responds:

“And every two years we relearn the sad fact that U.S. adults are less willing to accept evolution and the big bang as factual than adults in other industrial countries. Except for this time. Was there suddenly a quantum leap in U.S. science literacy? Sadly, no. Rather the National Science Board, which oversees the foundation, chose to leave the section that discussed these issues out of the 2010 edition, claiming the questions were ‘flawed indicators of scientific knowledge because responses conflated knowledge and beliefs.’ In short, if their religious beliefs require respondents to discard scientific facts, the board doesn’t think it appropriate to expose that truth.”

However, the National Science Board was right that the section  confused knowledge and beliefs. For example, there is evidence for the Big Bang theory and many people know about it, but they have not incorporated it into their beliefs.  Only physicists and mathematicians would likely know what a singularity is, let alone believe the universe arose from one. Then, there is the problem of how the singularity came to be. Likewise, many people know of the adaptation of species to their environment such as resistance of viruses and bacteria to antibiotics and of insects to DDT. They may also be aware of our ancestors such as Luci and Ardi and know of the evolution of the horse. However, if you insist that the spontaneous generation of life is part of evolution, it may be rejected.

Dr Krauss is missing something important.  Aristotle established science as a method for understanding nature by using observation and reason. It is not a body of facts to be memorized and believed. As scientists gather more evidence, what we now regard as fact may be replaced with better ideas. We should not make “accepting evolution and the big bang as factual” a litmus test for science literacy. Just as scientists think religion should not be dogmatic, scientists should also refrain from dogmatism. Insisting people accept scientific theories which conflict with their religious beliefs  just makes them more likely to mistrust science on issues where it really matters.

As a practical matter, it is not likely that someone’s mind can be changed by claiming their beliefs are wrong or that they are based on mythology. Science teachers must deal with students who already have a belief system established. Their strategy should be to present science as a method that uses observation and reason to understand the physical world. Teachers must focus on the background knowledge and the evidence, and hope that at some point the student would see any conflicts and try to resolve them.

1)http://www.nsf.gov/statistics/seind10/c7/c7h.htm

2) http://www.scientificamerican.com/article.cfm?id=faith-and-foolishness