Tuesday, May 30, 2017

Particle Reality

Our recent posts concerning air pressure did not address the sequence of scientific discoveries concerning the causes of air pressure. Only in the last two centuries were concepts of the particle theory of matter proposed. Ancients such as Democritus (430 BC) conceived of matter composed of particles. This was more a philosophical than a scientific discovery. Real progress was made just over two centuries ago when experimental evidence discovered by John Dalton (1766-1844) and Joseph Proust (1754-1826) showed that matter is composed of discrete particles—separate and distinct entities—and that all particles (atoms) of any one element are identical in mass and properties. The particles seemed indivisible and indestructible and could combine to form compounds. Experiments demonstrating that when one substance combines with another substance, mass proportions of the reacting substances are always constant. Scientists reasoned this would be true only if matter behaved as if composed of discrete particles.

Daniel Bernoulli (1700-1782) preceded Dalton and Proust in his proposal of particles, describing air pressure in terms of what was happening at the level of particles. More knowledge was gained later about gas, liquid, and solid particles. Bernoulli was ahead of his time, thinking microscopically instead of macroscopically. We quote Bernoulli as he described his experiments on the behavior of gases within closed cylinders: “Let the cavity contain very minute corpuscles which are driven hither and thither with a very rapid motion: so that these corpuscles, when they strike against the piston and sustain it by their repeated impacts form an elastic fluid which will expand of itself if the weight is removed or diminished…”

Preceding Bernoulli by many years, Evangelista Toricelli (1608-1647) invented the barometer to measure the strength of air pressure macroscopically. He did not explain  his barometer in terms of kinetic movement of trillions of particles. Rather, he described the behavior of the entire system and quantified the strength of air pressure. In this way he was more focused on effects rather than causes. Toricelli’s work with the barometer was initially suggested by Galileo for whom Toricelli worked briefly.

People attempting to pump water from wells have long observed that the water level  rises to a maximum level by creating a vacuum in a pipe above the water. The height of rise is approximately 34 feet. If water is raised to this level, in effect we have created a type of water barometer to measure the strength of air pressure. Toricelli developed a barometer using mercury instead of water. Liquid mercury is 13.6 times the density of water. Therefore, a mercury barometer is more compact than a water barometer and able to rest comfortably on a classroom lab table. The mercury barometer measures the identical force as the water barometer, but more conveniently.

A mercury barometer in my classroom was a special demonstration for observing daily changes in atmospheric pressure. We filled a narrow glass tube completely closed at one end with liquid mercury, inverted the covered open end of the tube, and placed it below the surface of mercury in the dish. When we removed our finger from the tube of mercury, its level dropped to an average height of 760 mm (29.92 inches) above the surface of mercury in the dish. Several inches of empty space remained above the mercury level in the tube. If we were successful in preventing an air leak into the tube, the space above the mercury was a perfect vacuum. If a small hole were drilled into the top of the closed glass tube to allow air inside, the mercury level would immediately fall to 0 mm. Our barometer would have become non-functional. In the classroom barometer the mercury level varied almost two inches during our weather unit study. Class members were able to correlate high readings with fair weather and low readings with storms and precipitation events.

In 1844 the first aneroid barometer was constructed with a movable needle attached to a small sealed flexible metal box which changed its size and shape with increasing or decreasing atmospheric pressure. Aneroid (non-liquid) barometers are more convenient than mercury barometers. Digital barometers may now be found in some smart phones!

The topic of air pressure is one of multiple examples of non-obvious causes affecting physical events in our environment. It is one of the most crucial phenomena in sustaining healthy function of Earth’s millions of different living creatures. A topic such as air pressure is able to inspire the imagination of young people and adults alike to express enthusiastic wonder at our unique planet’s hundreds of interrelated working systems. Science has enabled humanity to appreciate causes and effects of these many working systems. The Creator has enabled humanity not only to benefit by Earth’s working, life-sustaining systems, but also to understand how the systems operate.

Returning to the timeline of human discovery of the particle theory of matter, we remind readers of our previously discussed discovery pioneers: Toricelli, Bernoulli, Proust, Dalton. Each contributed to the logical sequence eventually culminating in our present knowledge of the particle nature of matter. Many other discoveries concerning components of basic particles ensued in the late 19th and early 20th centuries, including identification of electrons by J. J. Thomson (1897), protons by Ernest Rutherford (1911), and neutrons by James Chadwick (1932). In 1964 Murray Gell-Mann proposed quarks as constituents of protons and neutrons. Our knowledge of the wonders of non-obvious causes has only begun. How many more discoveries about the wonders of physical matter are yet to be discovered in future decades?

We are surprised that in our day faith in the existence of the Designer and Creator of All Things sometimes seems diminished as scientists have increased our knowledge of how the world works. Should it not be the opposite? Stated a different way, increasing evidence of design and fine-tuning of our physical systems sometimes generates increased scorn for the concepts of intelligent design and divine creation in many quarters. It is the goal of this blog to reverse this trend with both our young people and with acquaintances of all ages.    




Wednesday, May 24, 2017

Air Power

Our choice of “Air Power” for this post evokes multiple images. Are we talking about  military strategy, an aviation technology, or a cleverly named industry? Few search engines offer air power as a synonym for air pressure. When we deal with multiple aspects of the topic of air pressure, however, we suggest power is an appropriate alternate term. Air pressure is a dynamic, powerful force to be reckoned with in many aspects of human experience. Some do not understand the causes and effects of air pressure. The current post investigates the possibility of “Air Power” as a synonym for air pressure. 

Events in our world are explained with a healthy measure of questioning and investigation. Explanations rely on scientific method for answers to our questions. Natural curiosity of children and adults is not age limited. Answers are provided by experiments performed in the science classroom and in everyday life. Solid learning is provided by skillfully presented demonstrations and the help of the instructor to explain difficult or mysterious results.

The power or pressure of invisible air surrounding us provides fascination and wonder. In a physics classroom instructors may stress definitions and distinctions for terms they use. (One reference book listed 14 different definitions for power and a similar number of definitions for pressure—an illustration of the richness and sometimes challenging aspect of the English language.) Use of “power” in this context relates to the total output of energy available. In this sense, the “power” of air is almost unlimited on a planet such as Earth enveloped by an air blanket. In contrast, “pressure” could relate to an effect experienced at a specific location. For example, in describing the results of our “crushed can” experiment (4-30-17 post) we focused on the effect of air “pressure” at only one location—the spot where our can demonstration took place. The “crushed can” experiment, however, could be performed anywhere and everywhere on the Earth simultaneously.

A famous effect related to the pressure and power of air was discovered by Daniel Bernoulli (1700-1782), a mathematician and scientist. He reported on the phenomena that air pressure in fluids such as air is reduced when the fluid is in motion. The effect he described is known today as Bernoulli’s Principle. Bernoulli explained that air always flows from a region of higher to lower air pressure. We first relate several simple lab experiments or classroom discussions related to the principle.

In keeping with our preference for somewhat spectacular demonstrations, we describe several which seem to contradict common sense. We took an old fashioned thread spool with an open shaft through the middle and placed a piece of oak tag on the open end. After sticking a straight pin through the paper and into the spool to stabilize the cardboard, we forced our breath into the spool from the opposite end. Without an air flow gravity causes the cardboard to fall to the floor. When the air flow began, the oak tag defied gravity and remained on the spool. When we blew harder, the stiff paper oak tag adhered to the spool even more tightly. When the student stopped blowing into the spool, gravity took over and pulled the cardboard to the floor. 

A ping pong ball remained suspended indefinitely in a vertical stream of air above a hair dryer. The rapid air flow from the hair dryer possessed less air pressure compared with the motionless air outside. Higher pressure flowing from still air to moving air kept the ball within the moving, lower pressure air. A dangerous application of Bernoulli’s Principle occurs in city subway systems. Subway trains rushing by at high speed creates a moving air flow. Air pressure behind the passengers is higher in the motionless air. Therefore, one feels “pushed” toward the moving train. “Stay behind the line” is a multi-purpose safety warning. For a similar reason, drivers on interstate highways feel themselves being pulled toward a large truck if it passes closely at high speed.

Finally, our last example comes from modern aviation. Airplane wings are constructed with a slight curve over the top but are flat on the bottom. On takeoff, when sufficient air speed is achieved, the pilot pulls back on his flight control stick in order to begin the ascent. According to Bernoulli’s Principle, faster moving air exerts less pressure than slower moving air. Over the top of the wing the air is forced to travel a little faster than air at the bottom in order to rejoin as the wing slices through the air. Therefore, airplanes are “lifted” into the air by greater air pressure acting on the bottom of the wing. Many other complex issues are involved in the science of aeronautics. The principle described by Bernoulli was posed long before airplanes became a reality. I link the following post from 5-20-15 for our readers’ enjoyment. Bernoulli articulated a principle that may have preserved my life in 1952:

The phenomenon of air power or air pressure supplies a spiritual object lesson. The power of air pressure is available over the entire area of Earth. At any moment in time, the power of air and air pressure is virtually limitless. The God of Creation has designed hundreds of systems by which humanity and all other living things enjoy a rich physical existence. God also makes spiritual power available. His physical and spiritual power is limitless and independent of the constraints of time, space, matter, and energy in which we exist. God created our dimensions of reality, but he exists in a realm beyond our dimensions as well as within our temporal realm. 




Friday, May 19, 2017

Pressured and Sustained by Air

Air pressure is a subject of fascination apart from its relationship to the complex phenomenon of Earth’s weather system. Our planet manifests multiple physical systems worthy of investigation—systems ranging from small to large and simple to  complex. The subjects of air and air pressure are examples of systems which appear to become increasingly complex as we discover the interrelationships of multiple systems. Sub-systems interlock to form complex systems.

One example of a simple system begins with air. Upon study we discover simpler sub-systems: Air is composed of molecules of nitrogen (two atoms of nitrogen chemically linked) and molecules of oxygen (two atoms of oxygen chemically linked). Nitrogen and oxygen are two of eight diatomic elements. Even more simple is the system of individual atoms. Each atom of nitrogen or oxygen can be considered a system. Atoms are wonderful examples of fine-tuning and design, from the consistent forces holding their electrons to the nucleus, to the identical masses of each proton, neutron, and electron.

Our air blanket is held close to the earth’s surface by the force of gravity. If there were no gravity there would be no air clinging to the planet’s surface. In our atmosphere all of Earth’s weather occurs. The weather system would not exist without an atmosphere. Of course, virtually all earth life depends on the components of the atmosphere—oxygen for animal life and CO2 for plant life. The dynamic blanket of air must cling to the earth and be able to move, mix, and transport life sustaining water vapor from place to place. Moving air is termed wind. Dynamic connotes forceful, powerful, and energetic. Hundreds of physical requirements must be fulfilled and hundreds of processes must be completed successfully in order for human and other life to exist.

Changes in air pressure from one Earth location to another are a necessary pre-requisite for producing moving air. Air pressure varies according to temperature and altitude. Cooler air possesses higher pressure; warmer air possesses lower pressure. Several factors result in global temperature variability. The primary factor is varying solar radiation. When the sun’s rays strike Earth at a high angle near the equator, the earth receives more heat; it becomes warmer. In contrast when the sun’s rays strike the earth at a low angle at high latitudes, the planet receives less heat. We have contrasting temperatures—cold at the poles; warm at the equator.

Wind results from the tendency of higher pressure air to flow toward regions of lower pressure. Light winds result from adjacent areas with a moderate pressure difference. Strong winds result from substantial differences in pressure—there is a strong pressure gradient because strongly different pressure zones occur near each other.

Diagrams of Earth’s wind belts remind us of the importance of differences in air pressure existing from one location to another. Wind belts result from the tendency of air to flow from high to low pressure. A large portion of earth’s population exists in wind belts termed prevailing westerlies or northeast/southeast trade winds. Wind belts converge or diverge in their effort to equalize pressure conditions. In terms of our healthy, dynamic weather system, these effects are necessary. Absence of differences in pressure would result in the absence of wind, the absence of precipitation-producing storm systems and the absence of a mechanism for distributing life giving water where it is needed. It is not difficult to imagine that earth life would be very different if it would exist at all.

Looking back on my personal classroom teaching experience during weather units, we trust that after many years my former students may still relate the “wow factor” of our crushed can and vacuum pump demonstrations (5-11-17 post) to the importance of air pressure as that topic relates to the welfare and survival of life on this unique planet. Earth’s weather is a complex system for which success depends upon the effective working of many supporting sub-systems. Who could deny the supernatural design features of our weather system as well as thousands of other working systems enabling the existence of life on our Earth system

Earth’s life sustaining weather system is a marvel of complexity and beauty. Many other systems yield their secrets of design and the supernatural intelligence of the designer, the Creator of All Things. As parents and teachers of both young people and adults, we must first discover for ourselves the sense of wonder at the many operating systems surrounding us.


Thursday, May 11, 2017

Non-Obvious Causes

When we think scientifically, we are acutely aware of the cause and effect phenomenon. Causes are easy to observe in some cases. For other situations causes are difficult to observe without devising appropriate observational strategies. Before the Scientific Revolution empirical observations were not systematically utilized. At the onset of the Revolution implicit powers of men’s minds yielded to a greater dependence on evidence, both experimental and observational, and rational analysis. Formal science methodology achieved prominence during the Revolution along with a heightened awareness of cause and effect. 

Science experiments in our classrooms depend on traditionally accepted methodology. Some experiments are designed with the “wow factor” in mind in order to capture the attention of our young scholars. In this day of graphic displays of contemporary technological wizardry, we sometimes “sell” our science based upon how spectacular our science demonstrations are. They may be spectacular indeed.

Example 1: (I plead guilty of appropriating the “wow factor” on some occasions in my science classroom.) The “Egg in the Bottle” experiment is a classic science classroom spectacular. Air at sea level (most locations are somewhat above sea level) exerts a pressure of 14.7 lb./sq. in. If this substantial pressure is enlisted to push a hard boiled egg into an old-fashioned milk bottle without touching the bottle, we reap the “wow factor.” Observation of this classic experiment may help us determine a non-obvious cause after we observe a startling obvious effect.

The diameter of a peeled, hard boiled egg is larger than the the diameter of the mouth of the milk bottle. We could have challenged a student to push the egg into the bottle manually. He may have succeeded using considerable force, ruining the egg in the process. Our teaching challenge was to instruct students concerning the presence and strength of invisible air pressure. We must permit normal atmospheric air pressure to accomplish the task without our help..

The teacher folds a strip of newspaper and lights one end. He drops the burning paper into the bottle; the paper burns and is quickly consumed. Smoke pours out of the bottle along with heated air which expands out of the bottle. We quickly place one end of the egg on the mouth of the bottle. The egg almost immediately pops into the bottle followed by student “oohs” and “aahs.” After discussion students conclude there is less air in the bottle after the smoke and hot air air are expelled. Consequently, there is less air pressure inside the bottle than outside. Students conclude that the pressure of normal outside air pressure forces the egg into the bottle toward the now lower pressure. Discussion generates reminders that air always flows from a higher pressure to a lower pressure region. The egg obeys this “rule” of nature. The pressure differential does not have to be great for the experiment to succeed. Many students propose that the egg enters the bottle by “suction.” I respond, “Suction never did any work.” The egg is forced into the bottle from the outside, not from the inside. 

Example 2: The vacuum pump demonstration was another spectacular attention-getter and a wonderful teaching tool. A bell-shaped glass cover (the bell jar) on a platform is sealed shut and the pump motor started. Most of the air inside the bell jar is removed after a few minutes. When invisible air is removed we notice no obvious change. But when we place various objects into the bell jar and turn the pump on, we notice remarkable effects from the non-obvious cause: removal of air and subsequent lowering of air pressure.

A partially inflated grapefruit-sized balloon maintains its shape inside the bell jar before the pump was started. Air pressure inside the balloon is equal to air pressure outside the balloon. The air pressure forces of both air regions are balanced, but when air was removed from the outside of the balloon, the forces of air pressure inside and outside the balloon became unbalanced; the balloon began to expand. Outside air pressure was diminished—air inside the balloon remained the same. The ballon soon expanded from the force of air pressure inside the balloon, stretching the balloon to its breaking point.

Students are challenged to stretch the rubber of an uninflated balloon by hand to resemble its size and shape before the pump motor was turned on. They discovered that assignment is impossible. A little bit of air inside the balloon however, accomplishes the trick with the greatest of ease. Students determine that “a little bit of air” inside the balloon exerts an exceedingly powerful force in order to expand and pop the balloon. We need only to reduce the external pressure to visually observe the effect of internal air pressure.

Several other vacuum pump demonstrations became classroom favorites. One was expanding a marshmallow to many times its normal size. When we allow air back inside the pump, the marshmallow gives away its secret: it is filled with multiple little air compartments acting initially like little balloons. The marshmallow ends up tiny and shriveled. A somewhat more difficult demonstration to understand is “boiling cold water.” We boil tap water without raising its temperature. Lowering the air pressure permits water molecules to escape more easily. (Water molecules are always “trying” to escape.) The water molecules burst through the surface of the water more easily unimpeded by normal air pressure. The boiling point of liquids relates to both temperature and air pressure.

Many non-obvious causes in our world result in startling effects. The Creator of all things authored all physical laws of our universe. This authorship results in an incredibly ordered world. God, therefore, is not only the Creator, but also the Lawgiver. We rejoice in the love and omnipotence of our Lawgiver.           




Thursday, May 4, 2017

A World Working Well

Our current focus on the wonders of air pressure directs us to some deeper questions. It is appropriate to backtrack somewhat to discuss a few questions about constantly moving sub-microscopic atoms and molecules. Children and adults fascinated by air pressure will profit from a discussion of the structure and characteristics of atoms and molecules. In the case of oxygen, nitrogen, carbon, argon and all other atoms found in air, the atom is a marvel of structure and predictability. The nucleus, where over 99% of atomic mass occurs, is composed of tightly packed protons and neutrons held together by one of the four fundamental forces of nature—the strong nuclear force. Electrons swarming around the nucleus are kept in place close to the nucleus by another fundamental force—electromagnetic force.

How is our discussion related to air pressure? The atmosphere is composed of oxygen, nitrogen, argon, carbon, and other elements. Components of air molecules—protons, neutrons, and electrons—cohere by powerful forces. Two of the four universal (or fundamental) forces, the strong nuclear force and the electromagnetic force insure that these atoms hold together instead of generating a chaotic mass of protons, neutrons, electrons, and smaller particles such as quarks which compose them. Without the ever-present universal forces, our world’s matter would not exist as we know it. For example, some scientists humorously write that the protons in the nucleus of every atom in our universe have no business holding together in their densely packed condition. They are all positively charged particles in close proximity. Like charges repel. Why don’t the seven protons in nitrogen atoms and the eight protons in oxygen atoms fly apart? The answer lies with the strong nuclear force holding the particles together within the atoms’ nucleus.

For children and adults a discussion of the wonder of air molecules responsible for Earth’s ubiquitous air pressure phenomena may be appropriate. Diatomic molecules of nitrogen and oxygen composing 99% of our atmosphere each have nuclei which cohere by the strong force. In our last post (4-30-17) we stated there are 2.5 septillion air molecules in one cubic meter of air. Consider a smaller volume: In one cubic inch of air there are 440 quintillion air molecules at sea level. With either volume of air we deal with inconceivable numbers of molecules.

Especially curious older children and adults may understand that molecules of air are unlike simple sub-microscopic beads zipping around. Air’s uncountable billions of molecules zig-zag around at 1000 mph. Air possesses atoms whose components are held together by the strong nuclear force. When we discover the 14.7 lb. per square inch force of air pressure from air molecules colliding with any surface they contact, we have additional reasons to express open-mouthed wonder.

Children in Middle School learn basic atomic structure: protons, neutrons, and electrons. In subsequent years they study additional truths about the matter in air as reported to us by particle physicists. We trust that heavy scientific truths do not tire our young people prematurely. Parents and instructors must be alert for teachable moments. We propose that discussions or demonstrations of visible vs invisible forces are appropriate even for young children.

A startling New Testament passage occurs in the Book of Colossians. We do not quote these verses as a “proof text.” The Colossians passage may bring to mind a sometimes lively discussion of a little known term: Concordism. Some theologians believe that scripture provides explicit modern scientific truths. For example, they believe almost everything we wish to discover about creation events or the age of the earth is revealed by Bible passages. Such people are called “hard concordists” by astrophysicist/theologian Hugh Ross. In contrast, Ross describes “soft concordists” as less rigid. They “seek agreement between properly interpreted scripture passages that describe some aspect of the natural realm and indisputably and well-established data in science.” 

With the definition of “soft concordism” in mind, we quote from Colossians 1:16-17: “For by him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by him and for him. He is before all things, and in him all things hold together.” (Colossians 1:16-17 NIV.) These verses reference (1) the initial creation event, (2) two realms of existence, temporal and eternal, (3) visibility and invisibility, (4) purpose of creation (for him), (5) time frames (before all things), and (6) holding together (coherence) of matter. The Colossians passage is startling because centuries before the scientific revolution of the past 400 years, the Apostle Paul expressed these powerful scientific insights. Whether or not this is an example of hard or soft concordism, the passage reinforces our collective worship experience.

The concept of “a world working well” has broad significance. It could mean working well spiritually, socially, politically, or a host of other operational possibilities. In the context of our blog, we stress working well in a physical and scientific sense as affirmation of the past and present work of the Creator and to provide support for belief in the existence of God. If our world does not work well in a physical sense, our experience in other spheres of existence is weakened. Worse, If our physical world were to operate chaotically and unpredictably, the supporting framework of our physical existence may not exist. 

Depending on their age, children may be aware of protons and neutrons in atoms of air molecules. The mass of every proton and the mass of every neutron is identical and constant within their nuclei. The force binding protons together with neutrons in the nucleus, the nuclear strong force, is also constant. A slightly heavier or lighter neutron or a slight strengthening or weakening of the nuclear strong force would preclude life on Earth. Even one of hundreds of other slight changes in our working well world would make life on Earth impossible. 

We used Earth’s atmosphere and air pressure as a launch point of discussion. Each of quintillions of atoms in a single cubic inch of air obeys fundamental physical constants and universal laws of force.    

We link our post from 8-4-2008: