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Archive for the ‘Education’ Category

Academic Freedom and Democracy – ALEC Style

Sun ,23/06/2013

Academic freedom is one of the cornerstones of our educational system, so who could be against it? Representive Gus Blackwell introduced into the 2013 Oklahoma legislature HB 1674, called the “Scientific Education and Academic Freedom Act”. But there was something strange about the bill, as science teachers in Oklahoma already have a system ensuring  academic freedom. And, the bill only insured Academic freedom in four areas which Representative Blackwell deemed controversial, specifically “biological evolution, the chemical origins of life, global warming, and human cloning”. Mr. Blackwell’s education and expertise is in religion and business administration, so it’s unusual that he knows what is controversial in science. Oklahoma scientists and science educators were almost unanimously opposed to the bill as it is their opinion that there is virtually no scientific controversy on the core facts of global warming and evolution.

The bill allowed “teachers to help students understand certain information about scientific theories; disallowing State Board of Education, district boards of education, and certain administrators from prohibiting teachers from helping students understand certain information about scientific theories.”  Perhaps the bill would have been more aptly named the “Freedom from Accountability Act”. Apparently Mister Blackwell had not thought this through. It would also shield any science teacher, no matter of what religion, who wished to introduce their beliefs into their science classes. The bill even had an emergency clause providing that it be enacted immediately with a letter sent to school officials informing them of the decision. And, why is this now an emergency? The bill passed Oklahoma’s education committee by one vote, but fortunately for the quality of science education in Oklahoma, the 2013 session ended without it coming up for a vote. But, you can be sure it will be back.

The unusual nature of this bill can be understood as similar bills, with almost exactly the same wording, have been introduced in about 20 states. It is one of the “model bills” being promoted by the American Legislative Exchange Council (ALEC). ALEC is composed of over 300 special interest groups and corporations such as Exxon Mobile, AT&T, pharmaceutical companies, and Koch Industries. They sponsor conferences where their representatives  meet with state legislative members to collaborate on “model bills” and to draft legislation favoring their special interests. ALEC now has over 1000 “model bills”, many of which seek to limit workers rights, limit corporate liabilities, oppose environmental regulations, cut taxes, oppose universal health care, and to privatize such things as education, workmen’s compensation, and the prison systems.

Though mainly supporting corporate interests, the legislation often gives a nod to religious groups and to conservatives to win their support. The state legislators take the “model bills” back to their respective states, often as their own work. It also carries an understanding that by sponsoring the bill, they will receive support for their reelection campaigns. ALEC has 501(C)(4)status as a charity, which makes it tax exempt and hides its motives and the identity of its donors. Although ALEC claims it is not a lobbying group, it is directly lobbying our state Congressmen while getting around laws that limit lobbying and require disclosures of lobbying activities.

Representative Blackwell is a member of ALEC and, according to Source Watch, used state funds to attend their meetings. His interest in the bill was probably to introduce creationism into science classes, but adding climate change to the “controversy” list aligns with the interests of the fossil fuel companies. A leaked document from the Heartland Institute, a Libertarian think tank funded by fossil fuel interests, showed that introducing doubt about climate change into science classes was one of their goals.

Bill Moyer recently had a program on how ALEC is undermining American democracy. Although ALEC claims to promote capitalism, it is actually the citizens who pay. Not only do many politicians attend their meetings at state expense, members of ALEC get a big tax break for their lobbying activities and our taxes still pay for privatized state functions.  Sourcewatch lists 25 Oklahoma legislators as members of ALEC and Governor Fallin was once ALEC’s woman of the year, which means she favored the needs of large corporations and of the wealthy long before she became governor. We just saw a number of ALEC sponsored laws make their way through the Oklahoma Legislature, much to the detriment of ordinary citizens.

 

(c) 2013 J.C. Moore

Those Amazing Hummingbirds

Sat ,12/01/2013

This is a guest post written  and filmed by Barbara Moore.

When I come back in another life, I want to come back as a Hummingbird. Well, that’s if I did believe that was possible. I mean, what could be better than to look like a beautiful petite fairy and sip sugar all day at feeders or beautiful flowers! Not to mention zipping around in elusive bird flight.  Anyway, I have had a fascination with Hummingbirds since seeing my very first one.

With that fascination, I have become a faithful feeder and watcher, never tiring of their fascinating behavior. Watching has naturally led to photography and I have many hummingbird photos and am always trying for one more. I have never been able to get a picture of one of the most interesting things I have observed.  Sometimes a hummingbird will fly in a downward arc,  then turn  and repeat the arc in the other direction and continue doing that  for a dozen or more times in the same path, as if  they were pendulum on a string.   Experts are divided on why they do that, but since it’s only the males and in the Spring, it is likely either a territorial or a mating behavior.

Shortly after we moved to our new house which backs up to a wooded area, I hung out my hummingbird feeder. After a few weeks I started to experience an odd phenomenon; every morning the hummingbird feeder was totally empty even though I had just filled it. As I wasn’t seeing more than a few hummingbird during the day, I decided to investigate. One morning I happened to get up before sunup and just happened to look out the window. Ah ha! I found my thief. There was a good sized raccoon sitting on the deck rail where he could stand on his back legs, reach the hummingbird feeder and guzzle to his heart’s content. I tried to get a picture of that but there just wasn’t enough light and as soon as I opened the door he took off like a rocket!  I have also caught squirrels hanging upside down and out from the tree, as this one, sipping from the feeders. Needless to say I came up with a way to hang my feeders away from rails and branches.

 

This Fall we had an exciting hummingbird event; about 15 hummingbirds came to our feeder all at the same time. We have lived at the same location for five years and never had this happen. It was kind of strange as we have had maybe one male who occasionally would allow a female a brief visit to the feeder all summer long. Then this happened all in one day.  For next  several days  there  were many hummingbirds  that came to the feeder, but not 15 all at one once. It was very exciting to be out on the deck with them as they were much less skittish. The sound is pretty amazing too.

This is a video of my best ever hummingbird experience. Hummingbirds must have been what inspired the idea of “fairies”.    The video is about four minutes long but if you watch it all you will see some very interesting behavior, especially at  about 1:40. The male usually tries to drive the others away but there were too many. And, turn up the sound a little and you will be able to hear them:

Amazing Hummingbirds

What Happens When the Earth Is Full?

Mon ,05/03/2012

 

The photo at the right, shot from Apollo 11 as the Earth rose over the moon, reminds us of how beautiful the Earth is.  It also reminds us, that though the Earth seems large to us, our space is limited and our resources are finite. What will happen when the Earth is full?
 
 The human population just reached the milestone of 7 billion people. Our population has been growing at the rate of about 2% each year which means that the population will double about every 35 to 40 years. If we do not reduce our birthrate or experienced some great catastrophe, the population will reach 14 billion by 2050 and 28 billion by 2090. It is rather hard to imagine what the Earth would be like with that many people and is almost assured that that will not happen. Estimates are that the number of people who can live comfortably on the Earth is around 9 billion. That estimate may be off a few billion if you include advances in food production and measures to reduce our rate of pollution. However, it should be clear that at some point the human population will grow larger than the Earth’s ability to support it. The graph in the article Limits to Growth and Beyond, Part 1, shows that may happen within the next generation. What will happen then?
 
That has never happened before to the human population, but there are examples in nature where population is limited to a small area, such as bacteria in petri dish. When the nutrients are gone, so are the bacteria. There are a few examples of mammalian populations where the species is confined to a small area and the natural predators are eliminated, such as a Moose population established on Isle Royale in Michigan, where there were no wolves.  The moose population grew rapidly until almost all the vegetation on the island was depleted and then the moose population declined dramatically due to starvation and disease. One of the best examples is this case study of the deer population on the Kaibab Peninsula in northern Arizona.

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

Bits and Pieces 12 : Should We Tax Unhealthy Foods?

Mon ,03/10/2011

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

Bits and Pieces 9: The Arctic Ice and the Inuit

Mon ,22/08/2011

“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.

(c) 2011 J.C. Moore

Science, Global Warming, and the Ice Age Mystery

Fri ,31/12/2010

In the early 1800’s, scientists began a search for the cause of the ice ages. That search has led to a discovery of the factors that affect the Earth’s temperature, an understanding of the current global warming, and the solution to the mystery of the ice ages. *

The Data: Science is a way of understanding nature by using observation and reason. Man has always been keenly interested in the weather, but temperature records before 1850 were mostly historical accounts of storms, heat waves, or when bodies of water froze. Thermometers came into use in about 1850, allowing more accurate temperature records. One of the most useful records is NASA’s graph of the Earth’s annual mean temperature, which was compiled from ships logs, weather stations, and satellite measurements. It serves as a scorecard for telling whether the Earth is getting warmer or cooler. NASA’s data has small random variations from year to year because of factors such as sunspots, weather events, ocean currents, and particulates from volcanic eruptions. However, NASA’s graph shows that the Earth’s temperature has clearly trended upward since 1880 – with the exception of a curious plateau from 1945 to 1975 followed by a steeper rise in temperature. The Earth’s mean temperature is now 1.3 F higher than in 1880, and the last decade has been the hottest on record. Any theories or causes put forward to explain the global warming trend must be consistent with the temperature observations.

Possible Causes: Nineteenth century scientists realized from geological evidence that the Earth had gone through many ice ages that alternated with ages of warmer climate. Much of the early research on global warming was a search for the cause of the ice ages. Scientists found that many small variables cause the Earth to warm and cool, but the main three causes are the Sun, particulates, and greenhouse gases.

The Sun’s output seems to have been reasonably stable over the last several million years. Satellite measurements over the last 30 years have shown that while solar radiation has declined ever so slightly during that time, the Earth continued to warm – so clearly changes in the Sun’s output is not the cause of the recent warming. The amount of sunlight the Earth receives does, however, depend on the Milankovitch Cycles. These cycles are small variations in the eccentricity, axial tilt, and precession of the Earth’s orbit that cause the solar insolation, the amount of sunlight the Earth receives, to vary slightly in predictable cycles. Ice core data shows that ice ages tend to occur in roughly 100,000-year cycles that match the timing of the Milankovitch cycles. The temperature between the ice ages and the warm periods, however, are much greater than would be caused by the changes in solar radiation alone. Though a clue to the cause of the ice ages, the Milankovitch Cycles are not the cause of the current warming. They predict a minor cooling trend, which began some 6,000 years ago, will continue for the next 23,000 years. The current warming trend is too rapid and in the wrong direction for the Milankovitch Cycles to be the cause.

Particulates cause the Earth to cool by reflecting incoming sunlight back into space. The role of particulates in cooling the Earth became apparent in 1816 when ash from the explosive eruption of Mt.Tambora caused that year to be called “the year without a summer”, worldwide. The curious plateau in NASA’s temperature record from 1945 to 1975 was primarily caused by particulates from sources such as WW II, atmospheric nuclear testing, and increased industrialization. Research during the early 1970’s showed a huge increase in aerosol particulates from power production, factories, and vehicles – and some alarmists even speculated that we might cause another ice age. Particulates are visible and cause immediate health problems, so by 1980 most industrialized countries had restrictions on particulate emissions. Particulates cannot be the cause of global warming, but reducing their sources can cause the temperature to rise as can be seen in the temperature record after 1980.

The Greenhouse Effect was discovered in the early1800’s when scientists realized that the Earth was kept warm at night because the atmosphere trapped invisible heat rays rising from the surface. Around 1860, John Tyndall identified the invisible rays as infrared radiation and found the main gases that trapped the heat rays to be water vapor and CO2. The amount of water in the air remains relatively constant because of the water cycle. When the humidity is low, water evaporates, and when the humidity gets too high, it rains. However, CO2 has no such restrictions. Since CO2 makes up only a few hundredths of a percent of the air, it was at first dismissed as a possible cause of warming, especially since it was thought that plants and the oceans would absorb any excess.

In 1896, Svante Arrhenius, while still pursuing the idea that variations in CO2 might be the cause of the ice ages, laboriously calculated the effect of cutting the amount of CO2 in the atmosphere by half. He found that doing so would lower the temperature of Europe by 4-5 C, perhaps enough to bring on an ice age. He also found that doubling the amount of CO2 might raise the temperature of the atmosphere by 6-7 C. No one was concerned as Arrhenius’ model of the atmosphere was very crude and it was inconceivable that the amount of CO2 in the air could ever double. Some scientists speculated that man should intentionally add more CO2 to the air to ward off another ice age.

As models of the atmosphere improved, a number of scientists tried to get a better estimate of the effect of doubling the amount of CO2 on the Earth’s temperature, but the increasing complexity of the models made the calculations daunting. A breakthrough came with the development of computers. In 1956, G.N. Plass calculated that doubling the concentration of CO2 in the air would cause a 3 to 4 C increase in the Earth’s temperature. ** Many dismissed his work, as it seemed impossible that CO2, which made up only 0.03% of the air, could have such a large effect on temperature. However, in 1997, J.T. Kiehl found that, under clear sky conditions, CO2 accounted for 26% of the greenhouse effect – with water vapor accounting for most of the rest. More recent research has confirmed their work . Clearly, CO2 could have a significant effect on the Earth’s temperature if it was increasing. But was it?

CO2: In 1900, Arvid Hgbom calculated the amount of CO2 emitted by industrial sources and, surprisingly, found that man was adding CO2 to the atmosphere at roughly the same rate as volcanoes. No one thought much of it as, at that rate, it would take centuries for the amount of CO2 to increase significantly. However, after a protracted heat wave during the 1930’s, Guy Callendar re-examined previous temperature and CO2 measurements and found not only that the Earth was getting warmer, but also that atmospheric CO2 concentrations were increasing rapidly. Callendar’s work was mostly ignored, but a few scientists began monitoring the concentration of CO2 more closely. Their results were sporadic but, by 1958, Charles Keeling had established accurate procedures for measuring atmospheric CO2. His lab was eventually moved to the Mauna Loa observatory, far away from most CO2 sources. His graph showing how CO2 varies with time, now called the Keeling curve, proved to be an important piece of evidence. It showed that the oceans and plants were not taking up CO2 nearly as fast as man was producing it. Over the last century, the atmospheric CO2 concentration has risen from 280 parts per million (ppm) to 385 ppm, a 38% increase, and the Earth’s temperature has risen by 0.8 0C, well in line with Plass’ prediction. The role of CO2 as the major cause of global warming had been convincingly established. There is yet one more piece of evidence that confirms that conclusion.

Ice Ages: It was now possible to solve the mystery of the ice ages. The Milankovitch cycles alone cannot explain the changes in the Earth’s temperature during the cycles, but the process becomes clear if CO2 is included. The ice core data shows that the concentration of CO2 falls to about 180 ppm during an ice age and rises to about 280 ppm during the warm part of the cycle. The changing CO2 concentration happens because the solubility of CO2 in water varies with temperature. In the part of the cycle where the Earth is warmed by the increasing solar radiation, the oceans release CO2, which further amplifies the warming by the greenhouse effect. In the part of the cycle where the solar energy decreases, the oceans cool, the CO2 dissolves again, and another ice age begins. The concentration of CO2 in the atmosphere is the “control knob” for the Earth’s temperature – and we have now turned the knob up to 380 ppm and are moving it even higher. The Earth will surely get warmer.

* Much of the historical data came from this excellent AIP article.

 **  Recent research in the Journal of Climate, covering the last five ice ages, has experimentally confirmed Plass’ estimate of the climate sensitivity.

(C) 2010 J.C. Moore

Aristotle’s Contribution to Science, Education, and Physics

Tue ,28/12/2010

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 15th 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. 5th ed. New York: Simon and Schuster, 1949

(5)  Ross, W. D. Aristotle. 5th 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

Science, Climate Change, and the Greenhouse Effect

Mon ,13/12/2010

In the 1800’s, scientist began to understand the role greenhouse gases  had in keeping the Earth warm. The greenhouse effect is now a well established scientific principle. Both the science and the data show that  current global warming is caused by the increasing CO2 in the atmosphere.

Greenhouse Effect: Most gardeners know how greenhouses work.  In the daytime, the sun’s radiation (visible and UV) comes in through the glass and warms the plants and soil.  The glass stops the heat radiation in the infrared (IR) region from passing back through and the greenhouse stays warm enough to keep the plants from freezing, even at night. The Earth works much the same way except greenhouse gases, primarily water and  carbon dioxide, play the role of the glass and trap some of the leaving IR radiation. Winter nights on Earth would be very cold without greenhouse gases.

Earth’s Energy Balance: Of the Sun’s energy coming to Earth, 30% is reflected immediately back into space by particles in the air, by clouds, and by the surface. Another 20% is absorbed by the atmosphere where it runs the weather cycle. The remaining 50% heats the land and oceans. All the absorbed heat is eventually radiated back into space as infrared radiation. It’s a balanced energy budget, 100% in and 100% back out. Anything that reflects more light back into space, such as an increase in particulate matter in the air, would cause the Earth to cool. Anything that delays the energy’s trip back to space, such as an increase in greenhouse gases, would cause the Earth to warm. There are many small things that affect the Earth’s energy balance, but the main three are the Sun, particulates, and greenhouse gases.The ash from the explosive eruption of Mt.Tambora in 1816 caused that year to be called the year without a summer, worldwide.

The Sun: Certainly a change in the Solar radiation the Earth receives would cause a change in  the Earth’s temperature. Small wobbles in the Earth’s orbit, the Milankovitch Cycles, are variations in the eccentricity, axial tilt, and precession of the Earth’s orbit. They affect the amount of solar radiation the Earth receives in predictable cycles. Both scientists and skeptics agree that these cycles are responsible for the Ice Ages that occur in roughly 100,000-year intervals. In the part of the cycle where the Earth receives more solar radiation, the oceans slowly warm and release CO2. The CO2 further amplifies the warming by the greenhouse effect. As the Earth moves into the part of the cycle where it receives less solar radiation, the oceans slowly cool, the CO2 dissolves back into the oceans and another ice age starts. The patterns of wobble in the Earth’s orbit are predictable and the model predicts that a minor cooling trend, which began some 6,000 years ago, will continue for the next 23,000 years. The current warming trend is too rapid and in the wrong direction to be a part of the Milankovitch Cycles.

The Sun also has cycles where its output varies slightly such as  Sunspots activity. They cause the amount of solar radiation to vary in approximately 11-year cycles. However, the effects of Sunspots are so small that they do not show up above the other small variations in NASA’s temperature record.(see below). Long term variations in the Sun’s intensity are not responsible for the current warming. The graph of solar irradiance from 1880 to the present in this article shows that the Sun’s intensity increased slightly from 1880 to 1960 and then has declined slightly since 1960.   Satellite measurements of solar radiation show also that the solar radiation reaching Earth has declined slightly over the last 30 years – yet the Earth still warmed.

Temperature Data: The best temperature data we have clearly shows the Earth is getting warmer. NASA has compiled the Earth’s average temperature for each year since 1880 by using ships logs, weather stations, and satellite measurements. In the graph below , each square dot shows how far that year’s average temperature was above or below the 1970 value.  Although the data varies widely from year to year because of random factors such as sunspots, weather events, ocean current, and particulates from volcanoes and man’s activities,  the trend is clearly upward. The solid red and blue lines are  moving averages, which make the trend easier to follow.

NASA's Temperature Data  Credit: NASA JPL GISS

Credit: NASA/JPL/MSSS

Temperature Trend: The greenhouse effect links some of the causes of the temperature trend to man’s activities. The trend took a turn upward in about 1920. That was when the automobile, industrialization, and energy production began further increasing the carbon dioxide concentration in the air. The trend was flat from about 1945 to 1975 and  that can be attributed mostly to particulates. There was an increase in particulates after 1945 from many sources such as WW II, atmospheric nuclear testing, and increased industrialization. Research during the early 1970’s showed a huge increase in aerosols from power production, increased industrialization, and vehicles and some alarmists even speculated that we might be causing another ice age.  Particulates are visible and cause immediate health problems so by 1980 most industrialized countries had restrictions on particulate release. During the period from1945 to 1975 the CO2 concentration had continued to rise but its effect had been masked by the particulates. Reducing the particulates in the air allowed the full effect of the CO2 to be felt, causing the Earth’s temperature to begin to rise again. The effect of particulates and the reliability of the temperature record can clearly be seen in the graph above. In 1991, Mt. Pinaturbo erupted spewing about 10 cubic kilometers of ash into the air which caused an immediate 0.3 °C temperature drop  for the entire Earth, lasting until about 1995.

Causality: Although the greenhouse effect is a well accepted principle, skeptics sometimes claim the correlation between global warming and CO2 does not constitute causality. However, G.N. Plass, in 1956, calculated the climate sensitivity of the Earth to CO2. He found that doubling the concentration of CO2 in the air would cause a 3 to 4 °C increase in the Earth’s temperature. A number of more recent studies have confirmed his work and have shown that, though the concentration of CO2 in the air is small, it accounts for about 25% of the greenhouse effect. No natural occurrences such as volcanoes, sunspots, fires, or dust storms can account for the major trend in the data. Certainly, the increasing amount of CO2 in the air is causing the Earth to warm.

Man’s Role: Man’s activities, mainly through deforestation and burning fossil fuels, have released large amounts of CO2 into the air. In the last century, man’s emission of CO2 from fossil fuels have increased to over 30 billion tons annually and the concentration of CO2 in the air has risen from 280 parts per million (ppm) to 385 ppm. The processes that remove carbon dioxide from the air takes decades or longer so as the carbon dioxide concentration slowly built up, the Earth became a better greenhouse. The concentration of carbon dioxide in the air is now 38% higher than in 1880 and the Earth’s temperature is about 0.8°C (or 1.3 °F) higher. Clearly, man’s activities are mainly responsible for increasing the CO2 concentration in the air – and the increasing CO2 concentration is causing global warming.

(C) 2010 J.C. Moore

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Bits and Pieces 4: Is It Safe to Fluoridate Water?

Sun ,07/11/2010

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, Learning Styles, and Politics

Sun ,12/09/2010

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