https://lessonsonscience.com

In the previous essay I discussed some possible scenarios for the formation of the earth and some of the possible features of the earth and its atmosphere. Now I would like to look at changing conditions of the atmosphere and the earth’s surface that allowed life to be created and survive.

Before life forms could survive, certain chemical changes had to take place. Simple organic molecules that could make copies of itself (replication) had to form. Whether this was DNA or RNA is hotly debated yet today. The original atmosphere lacked the most important gas necessary for present day life forms. Probably sometime between 3.4–3.3 billion years ago, the first form of life arose. This would undoubtedly have been an anaerobic form since there was no free oxygen in the atmosphere. In fact, oxygen probably would have been toxic to obligate anaerobes. (Believe it or not, there are anaerobic conditions on earth now and thus, anaerobic forms of life (a group of bacteria like organisms called Archaea). They may have been the first forms of life. To find anaerobic conditions you have to look no further than your cupboard where you might find a can of vegetables or a swamp where methane gas is being produced by methanogen bacteria. Viruses, which are so simple that scientists still are not sure if they are alive, are composed of either a DNA or RNA core surrounded by a protein cover. They exhibit most of life’s characteristics but may also be crystallized and stored for an indefinite period of time without any need for energy or exhibiting other life functions such as respiration (anaerobic or aerobic), responding to stimuli, adapting to changes in environment, etc. There is much debate on the next point but most scientists believe that the first forms of life were also heterotrophic meaning that they could not make their own food. The following geologic time scale taken from deviantart.com will perhaps put things in proper prospective

Other scientists believe that autotrophic (auto; self and trophic; food) (photosynthetic or chemosynthetic) forms of life evolved first. Chemosynthetic bacteria (chemoautotrophs) use inorganic chemicals such as hydrogen sulfide (H2S), ammonia, and hydrogen gas to obtain energy. But the prize for being the first photosynthetic (oxygen producing) organisms probably goes to the cyanobacteria, formerly called blue-green algae but relegated down from eukaryotes to prokaryotes based on transmission electron microscope (TEM) and scanning electron microscope (SEM) micrograpths. The terms prokaryote and eukaryote require some attention since they are cornerstone concepts in biology. Prokaryotes (bacteria and Archaea) are single celled organisms that lack a true membrane bound nucleus. The DNA which may be circular floats freely in the cytoplasm of the cell (pro; before and karyote; nucleus). Eukaryotes obviously have a nucleus. They may be unicellular, colonial, or multicellular. At any rate, the cyanobacteria probably introduced oxygen into the atmosphere which caused the demise of anaerobic forms of life and paved the way for aerobic forms. This probably occurred around 2.5 billion years ago. Again there is some question here as the next sentence will show.

 Perhaps around 3.3 billion years ago oxygen producing organisms called stromatolites, which are still alive today, began the vitally important process that we know as photosynthesis. These autotophs paved the way for all of the food producers alive today. For the next 2 billion years oxygen was pumped into the atmosphere that we know today.  Of course, many other changes were taking place on the surface of the earth during this time. Continental drift was constantly at work changing surface features and affecting the distribution of life forms. One collision about 1.5 billion years ago produced a supercontinent, Rodenia. Somewhere around 700 million years ago, the Cambrium Explosion resulted in a tremendous increase in not only the sheer number of organisms but also the diversity of life. Before then life was pretty well limited to the sea because of intense radiation from the sun. Once the ozone layer formed, terrestrial forms began to appear. From about 400 million years ago to about 300 million years ago, land was gradually conquered as both flora and fauna (plants & animals) flourished. During the ensuing Carboniferous Period, dense tropical swamplands over virtually all of the earth produced coal and oil in places like the Middle East. Coal was produced from plants and oil and gas from animals. Here is an interesting side story. Did you ever wonder how that region of the world which is desert today could be so rich in oil fields? Remember, the earth has gone through many climate changes including temperature and rainfall fluctuations. These are the two most important climate factors that determine the type of flora that inhabit an area which in turn, determines the type of fauna. Also at this time arthropods including huge insects dominated the scene and later amphibians followed when reptiles appeared and flourished. It appears from the story told in the rocks and ice that at about this time numerous eruptions in present day Siberia for millions of years produced poisonous gases that covered the globe killing 95% of life. A new supercontinent, Pangea, appeared. Soon dinosaurs dominated the earth. 

About 200 million years ago Pangea split thus gradually producing the continents we know today. And, of course, the date that everyone is familiar with, about 65 million years ago, some cataclysmic event resulted in mass extinction of the great dinosaurs. This time probably about 75% of all life disappeared. Louis and Walter Alverez several years ago verified the date using radioactive isotopes (14C dating). A thin layer of Eridium found in various places on earth all date to that date. Below that line dinosaur remains were commonplace; above that line virtually no remains are found. Whether it was a gigantic meteor or an asteroid or some other event is still questionable. But one thing is for sure; something really big happened. About 50 million years ago, the African and European plates collided. This collision produced the Alps including the Matterhorn, of which the northern half is from the European plate and the southern half is from the African plate. About 2 million years ago the first of many ice ages began to occur. Also, overflowing volcanoes in present day Panama probably created the land bridge (Central America) that connected North and South America.

The earth has had a long and varied history and it is still changing. In so many ways mankind has changed it and, unfortunately, not usually for the good. It is time for us to be better stewards of the earth and leave it a better place for our children and grandchildren.

In a previous essay I discussed constructive and destructive geologic forces that continue to shape and reshape the earth. Today I would like to concentrate on the planet’s birth and early (prebiotic) conditions. My purpose here is to provide facts where facts are known and discuss various theories (possible explanations). 

There have been and still continues to be many theories formed to try to explain the formation of the earth. One popular theory held that all the planets in our solar system were formed from hot gasses thrown off by the sun as it formed. An American geologist, P. C. Chamberlain proposed the Planetisimal hypothesis which says that the earth formed from coalescing solid particles. In 1788, Lord Kelvin (Kelvin temperature scale) proposed that the earth was much older than originally thought and believed the core was a molten liquid but he completely missed the (approximately) true age because he believed there was no source of continuing heat supply. A radioactive core consisting mainly of lead and nickel eventually provided the answer to the heat problem and now the scientific community estimates the earth’s age to be about 4.5 billion years. Robert Holmes in 1911 discovered radioactive dating and subsequent use of uranium (U235) in rocks is the primary basis for this. James Hutton, a Scottish geologist, had already predicted that the earth had a long history with many many gradual changes and based his predictions on fossil rock examination. However, the earth was not yet hospitable for life–not for about another billion years. First the earth’s core had to cool for about 100 million years which allowed the crust of volcanic rock to form. But there was no life supporting atmosphere. The primitive atmosphere probably consisted of water vapor, nitrogen, carbon dioxide, sulfur dioxide, and hydrogen by out gassing over millions of years of volcanic activity. Eventually the atmosphere probably became saturated with water vapor and the continued cooling of the earth would have allowed rain to fall (for millions of years) to form the oceans. By 4.0 billion years ago as much as 40% of the earth’s surface was probably oceans with a CO2 filled atmosphere. Eventually a rock hard enough (granite) formed to become the continents. As noted in an earlier essay, Alfred Wegner, a German meteorologist first proposed the Continental Drift hypothesis in 1912. He noted like fossils on separate continents and assumed they once were much closer together. He also noted, as many of you have, that continents such as South America and Africa seem to fit together like pieces of a jigsaw puzzle.  Since then the concept of plate tectonics (with ridges where new lava rises pushing continents apart and seduction zones where volcanic faults occur) has been substantiated. 

Credit to: pompeiiplates.weebly.com

The Continents move approximately 1 inch per year. The original source of earth’s water and, therefore, its oceans has been a subject of much debate. Some scientists have proposed comets provided at least some of the water while others believe that water frozen in meteors provided most of it over millions of years. Other scientists favor the idea that some of the coalescing “mini planets” might have collided to form the earth and might have already contained water in them. Perhaps several sources provided the water that was to become necessary for life.

I know there are many gaps and holes here but remember from an earlier essay it was pointed out that this is a part of the nature of science which makes it both challenging and interesting. I know there are skeptics reading this that, no doubt, will reject all of this and simply say that God created it and I firmly agree. But how did God create it? What methods did He use? The Bible doesn’t give many details. God also gave us a mind, the desire to learn about our world and beyond, an imagination to ask the important questions, and the capacity to dream dreams. He also gave us science and the “laws of nature” to study it. I have always said that knowledge of science will help reveal the mind of God. Science tries to answer the question of “how” and religion tries to answer the ultimate question of “why”

Biogeochemical cycles, as the name implies, are perfect examples of the fusion of concepts from various science disciplines. Principles of biology, geology, and chemistry are combined in these cycles. Each has important implications to all living inhabitants of earth. 

        The hydrologic cycle, also known as the water cycle, is the simplest of the cycles I will discuss here. The water cycle consists of three phases; evaporation, condensation, and precipitation. All are examples of physical changes. Heat from the sun constantly evaporates water from the earth’s surface. This includes sources as small as mud puddles to as large as oceans. As the water vapor rises into the upper atmosphere it cools and condenses. This condensation, also called cloud formation, requires microscopic dust particles that serve as nuclei which are necessary for raindrop formation. Under the right conditions, precipitation in the form or rain, sleet, hail, freezing rain, or snow will return the water to the earth to begin the process again. Since most of our weather in this part of the world originates far to our west, I often told my students that the rain we got last night might have come from as far away as Hawaii several days ago. The fact that our weather originates over vast quantities of ocean has far reaching consequences when we consider the effects that warmer ocean temperatures resulting from global warming and other phenomena have on weather patterns. I also made a special effort to point out that the amount of water that we have today is the same as what we have always had and presumably always will have. The basis for this lies in the Law of Conservation of Matter which essentially says that matter is neither created nor destroyed (with some exceptions like Einstein’s theories of relativity) but simply changed in form (chemical or physical). So why are we so concerned about having enough water if the amount never changes. I will answer that questing at the end of the essay. The following diagrams taken from the internet illustrates the water cycle, carbon cycle, and nitrogen cycle

 Credit to: nj.gov 

The carbon cycle is of great interest and concern since one of its principle components, carbon dioxide (CO2) has been identified as a major greenhouse gas and a contributor to global warming. All living organisms contain carbon atoms and, therefore, when they die and decay or are burned (after being converted to fossils fuels), CO2 is released as the carbon atoms combine chemically with oxygen atoms. Even waste products release CO2 as does cellular respiration. I will discuss the photosynthesis/cellular respiration cycle in a later essay but let me just say that plants remove CO2 from the air. The transfer rate of carbon from the atmosphere by photosynthesis just about equals the rate at which respiration and decay return carbon to the atmosphere. However, when fossil fuel burning is added to the equation, the rate of CO2 returned to the atmosphere is greatly favored. That is bad. In 1850, atmospheric CO2 was about 280 parts per million (ppm) and today it is about 350 ppm and climbing. Destruction of vegetation for any reason reduces the amount of CO2 sequestration from the atmosphere. Just think for a moment about the many ways that we remove vegetation from the earth’s surface. We can’t blame all of it on rainforest destruction

Credit to: slideshare.org

     Most of us know that nitrogen makes up about 80% of the atmosphere and that nitrogen is necessary for plant growth. But plants can’t just take nitrogen out of the air in its elemental form. It has to be “fixed” or changed into a form that they can use. That’s similar to us changing our food into forms our bodies can use. Certain kinds of bacteria in water and soil can fix nitrogen into ammonium (NH3+) or nitrate (NO3-) compounds so that plants can make amino acids, DNA, and RNA. Nitrogen fixation also occurs when organic matter decomposes. This includes animal waste. It should be noted that fertilizer use results in the release of nitrogen oxide (NO2), a greenhouse gas. Fossil fuel burning also pumps sulfur dioxide (SO2) into the atmosphere. Both nitrogen oxides and sulfur dioxide are converted to acids which eventually return to earth. Carbon dioxide combines with water vapor in the atmosphere to form carbonic acid, another form of pollution. Normally rain has a pH of about 5.6(slightly acidic). In many parts of the heavily industrialized northeastern United States, the pH of the rain is between 5.0 and 4.0 which is more acidic. In fact, a pH of 4 is ten times more acidic as rain with a pH of 5.  Has anyone ever heard of acid rain?

Credit to: data.allenai.org

    Now let’s answer the question I posed above. The real water concern is twofold. Will we have enough useable (unpolluted) water and will that water be distributed adequately on a global basis? There have always been arid regions and high precipitation zones but human activities are now exaggerating those extremes.

       With the recent devastating volcano in Hawaii, I thought it would be appropriate to discuss some natural geologic forces.        

       Earthquakes and volcanoes are, in geologic terms, called constructive forces. They can cause great destruction but here’s the point: they bring new material (lava, magma, volcanic ash, etc.) to the surface. These fertile rich materials supply the depleted soil for growing things in addition to changing the appearance of the earth’s surface. These are building up processes similar to anabolism in living cells that I will discuss in another essay.

      On the other hand, weathering and erosion are destructive forces because they tear down surface features and wear them away. The major agents of weathering include wind, rain, and temperature changes (freezing & thawing). Potholes in the pavement in the spring are a good example of the effects of freezing & thawing. The major agents of erosion are running water, wave action, wind, gravity, and loss of ground cover. Weathering and erosion can be compared to catabolism (tearing down processes) in living cells. It is interesting that constructive and destructive forces in geology are complementary processes like photosynthesis and cellular respiration are in biology. 

Once again we find that we humans constantly leave our “footprint” on these processes and, therefore, on the face of the earth. Drilling, mining, construction, logging, and farming are just a few ways in which we have altered the face of the earth’s surface and subsurface. Moreover, the effects of underground bomb testing by the United States and Russia years ago are not fully understood.

Let’s back up a little. Most of you have probably heard of plate tectonics and continental drift. The continents are moving and this movement can even be measured. Alfred Wegener, a German meteorologist first proposed the idea of continental drift in the 1920’s. The Rocky Mountains were formed where the Pacific and Continental plates collided; the Alps were formed where the African and European plates collided. Interestingly, some of the tallest mountain ranges are found under the Pacific and Atlantic Oceans. Iceland sits on the Mid Atlantic Ridge and is volcanic in origin. These ridges are where faults and volcanoes often occur. If there are ridges where continents collide, there must be trenches where separation occurs. Indeed, the Marianas Trench, which at over 7 miles deep, is deeper than the tallest mountain. These trenches represent subduction zones where one layer sinks below another pushing solid rock down where it is heated by radioactive elements to a molten liquid state and recycled again. This all lends support to the Planetesimal Hypothesis which holds that the earth and other planets were formed by cohesion of particles about 4.567 billion years ago. The asteroid belt between Mars and Jupiter probably represent particles that never quite formed a planet or one that broke apart.

To learn more about this and other topics I have discussed or will discuss in the future, check the Science Channel, National Geographic Channel, or the History Channels. In particular I would recommend the following series: Naked Earth, The Universe, or Miracle Planet

           In the last essay we learned about some of the earliest “branches” of science that developed and why. I also discussed a loose chronological order of scientific disciplines and named a few of the more prominent early scientists. I left one very important question unanswered. What is science? Once again we find no single answer that everyone agrees upon. But as I would tell my students, the beauty of science rests in its complexity and its ever changing nature. Two components stand out: the content of science and the process of science. The content, often referred to as the body of knowledge, is the aspect that, for better or worse usually is emphasized in a science class (facts, memorization, etc.). The process is what we usually refer to as the scientific method (s). You may recall from your science classes the general scheme (problem, hypotheses, experiment, observation, and conclusion) with more or fewer steps. It’s often more complicated than that but we all probably use a simplified version of it every day as a part of our thought processes. First of all, and this what sets science apart from “belief fields” such as religion, ethics, morality, or political ideology, the realm of science includes anything that can be observed and is “testable”. Science gathers, processes, classifies, and analyzes information. There is nothing wrong with belief fields for they often deal with right and wrong or good and bad and they certainly play a big part in my life. They operate on a belief or faith system which sets them apart from science. With that aside taken care of, let me return to the main points. As a part of the process of science, experiments and research are carried out as controlled experiments, that is the experimenter manipulates or controls all the factors (variables) that may influence the results by keeping all the variables constant except one . That one is the factor that is the focus of the experiment. Generally speaking, there are two groups, the control group and the experimental group. The experimental group will have all of the factors the same as the control group except for the one variable that is being tested. The experimental variable (also call the independent variable) is the one factor being tested. No more than one factor (variable) can be tested at one time; otherwise, you wouldn’t know which factor is responsible for the outcome of the experiment. For example, let’s say you want to test whether fertilizer is good for growing a certain type of plant. You may want to state an hypothesis as an if…then prediction. For example, you may predict that if I use fertilizer on the experimental group, then I would expect that group to grow faster and produce healthier plants. You would select several plants of the same kind and divide them into two groups, the control group and the experimental one. Both groups receive the same amount of water and the same length and intensify of sunlight. Both groups are grown in the same soil and at the same temperature and humidity. This is what we mean by a controlled experiment; you control or manipulate the environment. The only thing that is different is the fertilizer. The control group receives no fertilizer but the experimental group does. Therefore, fertilizer is the experimental variable and difference in the growth between the two groups, as measured by you, can be attributed to the effects of fertilizer.

         Allow me to comment briefly on direct vs. indirect evidence or observations. Most of what we learn about present conditions results from direct observations. Virtually everything we know about past conditions is derived from indirect evidence. The fossil record and core samples are two examples of indirect evidence.

         Let’s consider a few definitions. You may think you already know what an hypothesis and theory are. You probably learned in a science class that an hypothesis is an “educated guess” and a theory is a hypothesis that has stood the test of time. Those definitions may work in everyday language but not in science and should not be taught in a science class. An hypothesis is a possible explanation for an observed phenomenon and a theory tries to explain a series of related phenomena. I will discuss examples of both in future essays. The last point I would like to make here is that in science there are no absolute truths. The best that can be done is to either refute or substantiate a prior or present conclusion

One of the first questions I liked to pose to a new class was “what is science?”  So I pose that question now.  Two other follow-up questions were “when did science begin and what was probably the first “branch” of science to develop?”  Let’s answer the last question first.  Although there is no single correct answer, many people agree that ever since mankind inhabited the earth, people have looked up into the heavens and observed the stars and planets and their motion in space.  Out of the pseudoscience of astrology, arose astronomy.  However, it could not advance to a technical level until mathematical principles were well formulated.  Some people would argue that chemistry was the first branch of science to develop citing the alchemists who tried to convert some metals to gold and silver.  However, that was much later. They never succeeded in making gold but they did further the study of matter and its changes.  Biology could not really develop until a very important tool, the microscope, was invented.

There is again no universal agreement on when science or scientific thinking began but most agree that a significant step to ending the Middle Ages was the rise of science and, yes, technology.  Many scholars would point to Francis Bacon (1561-1626) as one of the first true scientists because he used an experimental (and empirical) method to systematically investigate questions of a scientific nature.   Bacon was also a statesman, writer, and philosopher. Other noteworthy early scientists include Nicolas Copernicus (1473-1543) who refuted the ancient and universally accepted Ptolemaic theory which held that the earth was the center of not only the solar system but the entire universe.  Copernicus proposed the heliocentric idea that the sun was the center of our solar system and the earth and other planets revolve around it.  Later Galileo (1564-1642) contributed much to the fields of physics and, of course, astronomy.  The latter two would gradually change the worldview of not only science but of religion and of man’s place and importance on earth. At about the same time, Johannes Kepler, (1571-1630) a German astronomer, proposed a mathematical model to explain planetary motion. He postulated that, among other things, planets move in elliptical (egg shaped) orbits, not circles.

No discussion of early scientists would be complete without including Isaac Newton, an English scientist. In his Mathematical Principle of Natural Philosophy, he married the disciplines of mathematics, astronomy, and physics. He described three laws of motion:
1. Inertia– acceleration depends on force and mass

2. Action and reaction– for every action there is an opposite and equal reaction (e.g. a jet or rocket engine)

3. The force of gravity depends on distance

I have purposely not answered the first question for two reasons.  I want the reader to think about what science is for a while and that will be the topic of the second essay.  Stay tuned.

I am repeating a post from a couple years ago as filler while I prepare a more serious essay on climate change. Hope you enjoy.

1. To warm up, here are few biology/chemistry “play on words” groaners.  In first year biology we usually learn three types of chemical bonds, ionic, covalent, and hydrogen.  (In AP biology we also learn disulfide bonds too).  During an ensuing review, after correctly identifying the above three bonds I ask the class for a fourth one for which, of course, no one had a clue.  Then I say “you mean you never heard of James Bond”!
2. In that same vein, to demonstrate diffusion I would usually place a beaker of water on an overhead projector and add a few drops of some colored substance (i.e. food coloring, KMnO₄, methylene blue, etc.) and we would all watch the substance spread throughout the water, The heat from the projector bulb would cause some movement but to enhance the process I would ask how we could speed it up.  Invariably someone would suggest stirring it.  As I raise the beaker I would say “shaken, not stirred.  Yes, I like James Bond too”.  (I do own every JB movie)  Want to know my favorite one?  “For Your Eyes Only” I especially love the fantastic skiing scenes.

Genetics Jokes

Answers at end of essay.What do you get when you cross a mink with an octopus?

3. What do you get when you cross a mink with a giraffe?

4.. While studying sex linked traits (now often called X-linked since the gene for the condition is on the X chromosome) we would eventually talk about hemophilia A or B in which mothers pass the condition to their sons.  The mother is, therefore, called a carrier (heterozygous) with one dominant gene and one recessive gene. Only under rare conditions can a daughter have the condition.  I’ll let the reader try to figure out the necessary scenario for that to occur. Hint; using a Punnett square let X^H X^H represent the homozygous condition (purebred), let X^HX^h represent the heterozygous (hybrid) condition for the female, let X^HY⁰  represent a normal male , and X^hY⁰ represent a hemophiliac male. The zero is because the Y chromosome has no gene for the condition.  A Punnett square looks like a tic-tac-doe figure. Let the male possibilities go on the top or left side and the female on the opposite one not used for the male,  Then fill in the four inside squares like you would read a road map mileage chart You may have to do several Punnet squares before you have a hemophiliac female. OK, I’ll give you the genotype you should end up with (X^hX^h.).Anyway, I would ask if a man can be a carrier.  The usual answer is no, which is correct.  Again the reader is challenged to figure out why not.  At that time I would say, “You mean you’ve never heard of a mail carrier”.

5. When studying varieties of corn: “Did you hear about the PGA convention in Chicago last week?  (PGA stands for Popcorn Growers of America, not Professional Golf Association). The man they elected president was called the “kernel” He pounded his gavel and declared “ladies and gentlemen, lend me your ears” Yes, that was a corny joke wasn’t it. And pretty a-maize-ing.

6. In general science class while holding a piece of mossy zinc near a beaker of water I would ask “Is zinc very heavy”?

Pause

As I drop it into the beaker, “Well, if I drop it into this beaker of water , it will zinc to the bottom”.

7. For  any occasion:  My first dog loved to be brushed.  He would either fall asleep or lick my wristwatch.  I guess that proves he was a good “watchdog”. But the real moral of the story is that “my watch takes a good licking and keeps on ticking”.

8. After a student answered several questions in a row. “I’d give you a hand but you already have two of them”.

9. When studying plant structure:  “Today we’re going to get down to the root of things”.

10. When studying the circulatory system: “Today we’re going to get right to the heart of things”.

11. Even some Biblical questions:  Where in the Bible does it talk about baseball?

12. Where is the Bible does it talk about tennis?*

13 .An acid/base titration is a cute little demonstration of color changes in liquids that also leads to a groaner.  The indicator phenolphthalein is colorless in an acid but turns pink to purple in a base depending on the pH.  I would add a few drops of phenolphthalein to an acid (i.e. hydrochloric (HCl), sulfuric (H₂SO₄), etc.) and then add a base (i.e. sodium hydroxide, (NaOH0 and when the pH rose above 7 the solution would amazingly turn color which always impressed the students.  Then I would say “You didn’t know I was a magician.  One day I was walking down the street (sidewalk) and I turned into a drugstore! 

14. One of my nieces gave me a coffee mug (my wife and I collect mugs).  Printed on the mug is the following: “Atoms don’t tell the truth, they make up everything”.

15.  Three beakers sitting on the demonstration table, two of them filled with water and third one empty I would ask “ What king does the empty beaker represent?”

2. Answer:  A coat of arms

3. Answer:  A fur coat with pocket.

11. In Genesis 1 it says In the big-inning

12. In Exodus it says And Moses served in Pharaoh’s Court

15. Fill-up (Phillip) the third

One of the first questions I liked to pose to a new class was “what is science?” So I pose that question now. Two other follow-up questions were “when did science begin and what was probably the first “branch” of science to develop?” Let’s answer the last question first. Although there is no single correct answer, many people agree that ever since mankind inhabited the earth, people have looked up into the heavens and observed the stars and planets and their motion in space. Out of the pseudoscience of astrology, arose astronomy. However, it could not advance to a technical level until mathematical principles were well formulated. Some people would argue that chemistry was the first branch of science to develop citing the alchemists who tried to convert some metals to gold and silver. However, that was much later. They never succeeded in making gold but they did further the study of matter and its changes. Biology could not really develop until a very important tool, the microscope, was invented.

There is again no universal agreement on when science or scientific thinking began but most agree that a significant step to ending the Middle Ages was the rise of science and, yes, technology. Many scholars would point to Francis Bacon (1561-1626) as one of the first true scientists because he used an experimental (and empirical) method to systematically investigate questions of a scientific nature.  Bacon was also a statesman, writer, and philosopher. Other noteworthy early scientists include Nicolas Copernicus (1473-1543) who refuted the ancient and universally accepted Ptolemaic theory which held that the earth was the center of not only the solar system but the entire universe. Copernicus proposed the heliocentric idea that the sun was the center of our solar system and the earth and other planets revolve around it. Later Galileo (1564-1642) contributed much to the fields of physics and, of course, astronomy. The latter two would gradually change the worldview of not only science but of religion and of man’s place and importance on earth. At about the same time, Johannes Kepler, (1571-1630) a German astronomer, proposed a mathematical model to explain planetary motion. He postulated that, among other things, planets move in elliptical (egg shaped) orbits, not circles.

No discussion of early scientists would be complete without including Isaac Newton, an English scientist. In his Mathematical Principle of Natural Philosophy, he married the disciplines of mathematics, astronomy, and physics. He described three laws of motion:

1. Inertia– acceleration depends on force and mass

2. Action and reaction– for every action there is an opposite and equal reaction (e.g. a jet or rocket engine)

3. The force of gravity depends on distance

I have purposely not answered the first question for two reasons. I want the reader to think about what science is for a while and that will be the topic of the second essay. Stay tuned

XXXI.  As I was writing. . . .

XXXII. Viruses with special emphasis on COVID-19

XXXIII. The Evolution of my Essays on Evolution

1. Natural Selection and the Nature of Science
2. Scientific methods and evolution
3. Genetics/evolution
4. Evolution & religion

XXXIV. Climate change-can you tolerate more?

          A. Anti-climate/anti-science Groups

          B. Recent Happenings

XXXV. Boone County Fair (a little side trip)

Above outline subject to change