NOTE: THE FORMATTING OF THIS DOCUMENT IS DIFFERENT THAN WHAT APPEARS IN THE COURSE, DUE TO THE LIMITATIONS OF WEB DOCUMENTATION

Module #1: A Brief History of Science

Introduction

This course will take you on a tour of what I consider to be the most interesting of all human endeavors: science . Now, of course, I am well aware that many people (perhaps even you) do not consider science to be very interesting. Nevertheless, I do believe that most people's dislike of science comes from bad curriculum and/or bad teachers, not the subject itself. Hopefully, as you go through this course, you will see why I find science so incredibly interesting, and if nothing else, you will at least develop an appreciation for this incredible field of study.

So what is science, anyway? Well, the word “science” comes from the Latin word scientia (sigh' en tee uh), which means “to have knowledge.” It can be generally defined as follows:

Science - A branch of study dedicated to the accumulation and classification of observable facts in order to formulate general laws about the natural world.

That's a nice definition, but what does it mean? It means that the purpose of science is to develop general laws that explain how the world around us works and why things happen the way that they do. How do we accomplish such a feat? That's where the “accumulation and classification of observable facts” comes in. The practice of science involves experimentation and observation. Scientists observe the world around them and collect facts. They also design experiments that alter the circumstances they are observing which, in turn, leads to the collection of more facts. These facts might eventually allow scientists to learn enough about the world around them so that they can develop a new law which helps us understand how the natural world works.

As with any other field, the only way to truly understand where we are in science today is to look at what happened in the past. The history of science can teach us many lessons about how science should and should not be practiced. It can also help us understand the direction in which science is heading today. In the end, then, no one should undertake a serious study of science without first taking a look at its history. That's where we will start in the course. This module will provide you with a brief history of human scientific inquiry. If you do not like history, please stick with this module. You will start to sink your teeth into science in the next module. Without a historical perspective, however, you will not fully appreciate what science is!

The First Inklings of Science (From Ancient Times to 600 B.C.)

Some of the earliest records from history indicate that 3,000 years before Christ, the ancient Egyptians already had reasonably sophisticated medical practices. Sometime around 2950 B.C., for example, a man named Imhotep (eem' oh tep) was renowned for his knowledge of medicine. People traveled from all over the Middle East to visit Imhotep, hoping that he would cure their illnesses.

Most historians agree that the heart of Egyptian medicine was trial and error. Egyptian doctors would try one remedy and, if it worked, they would continue to use it. If a remedy they tried didn't work, the patient might die, but at least the doctors learned that next time, they should try a different remedy. Despite the fact that such practices sound primitive, the results were, sometimes, surprisingly effective. For example, Egyptian doctors learned that if you covered an open wound with moldy bread, the wound would heal quickly and cleanly. As a result, most Egyptian doctors applied moldy bread to their patients' wounds. Modern science tells us that bread mold typically produces penicillin , a chemical that kills germs which infect wounds! Thus, even though the Egyptian doctors knew nothing about germs, they were able to treat wounds so that they would not get infected by germs!

Another example of the surprisingly effective art of ancient Egyptian medicine can be seen in the way they treated pain. In order to relieve a patient who was in extreme pain, Egyptian doctors would have the patient eat large numbers of seeds from a flowering plant called the poppy . Eating these poppy seeds would almost always relieve the patient's pain. Modern science tells us why this worked. Poppy seeds contain both morphine and codeine , which are excellent pain-relieving drugs still used today!

Now it is important to realize that although Egyptian doctors could heal people who otherwise would die, they still did not understand much about the human body. They didn't know why moldy bread helped wounds heal. They simply knew that it did, and therefore they used it.

Why was Egyptian medicine so advanced compared to the medical practices of other ancient nations? Well, perhaps the most important reason was the Egyptian invention of papyrus (puh pie' rus).

Papyrus - A primitive form of paper, made from a long-leafed plant of the same name

As early as 3,000 years before Christ, Egyptians took thin slices of the leaves of the papyrus plant, laid them crosswise on top of each other, moistened them, and then pressed and dried them. The result was a form of paper that was reasonably easy to write on and store.

The invention of this ancient form of paper revolutionized the way information was transmitted from person to person and generation to generation. Before papyrus, Egyptians, Sumerians, and other races wrote on clay tablets or smooth rocks. This was a time-consuming process, and the products were not easy to store or transport. When Egyptians began writing on papyrus, all of that changed. Papyrus was easy to roll into scrolls. Thus, Egyptian writings became easy to store and transport. As a result, the knowledge of one scholar could be easily transferred to other scholars. As this accumulated knowledge was passed down from generation to generation, Egyptian medicine became the most respected form of medicine in the known world!

Although the Egyptians were renowned for their medicine and for papyrus, other cultures had impressive inventions of their own. Around the time that papyrus was first being used in Egypt, the Mesopotamians were making pottery using the first known potter's wheel. Not long after, the Sumerians developed horse-drawn chariots. As early as 1,000 years before Christ, the Chinese were using compasses to aid themselves in their travels. The ancient world, then, was filled with inventions that, although they sound commonplace today, revolutionized life during those times. These inventions are history's first inklings of science.

As you progress through this course, you will see that it is divided into sections. Usually, at the end of each section, you will find one or two “on your own” questions. You should answer these questions as soon as you come to them in the reading. They are designed to make you think about what you have just read. These questions are often not very easy to answer, as you cannot simply look back on the material and find the answer. You must think about what you have learned and make some conclusions in order to answer the question. You will find your first “on your own” question below. Answer it on a separate sheet of paper and then check your answer against the solution provided at the back of this module.


ON YOUR OWN

1.1 Although the ancient Egyptians had reasonably advanced medical practices for their times, and although there were many inventions that revolutionized life in the ancient world, most historians of science do not think of Egyptian doctors and the ancient inventors as scientists. Why? (Hint: Look at the entire definition of science.)

True Science Begins to Emerge (600 B.C. to 500 A.D.)

As far as historians can tell, the first true scientists were the ancient Greeks. Remember, science consists of collecting facts and observations and then using those observations to explain the natural world. Although many cultures like the ancient Egyptians, Sumerians, Mesopotamians, and Chinese had collected observations and facts, they had not tried to use those facts to develop explanations of the world around them. As near as historians can tell, that didn't happen until the 6th century B.C., with three individuals known as Thales , Anaximander (an axe' uh man der), and Anaximenes (an axe' uh me nees). Many historians view these three individuals as humanity's first real scientists.

Thales studied the heavens and tried to develop a unifying theme that would explain the movement of the heavenly bodies (the planets and stars). He was at least partially successful, as history tells us he used his ideas to predict certain planetary events. For example, he gained a great reputation throughout the known world when he correctly predicted the “short-term disappearance of the sun.” What he predicted, of course, was a solar eclipse, where the moon moves between the earth and the sun, mostly blocking the sun from view.

Anaximander was actually a pupil of Thales. He was much more interested in the study of life, however. As far as we know, he was the first scientist to try and explain the origin of the human race without reference to a creator. He believed that all life began in the sea, and at one time, humans were actually some sort of fish. This idea was later resurrected by other scientists, most notably Charles Darwin, and is today called the “theory of evolution.” Later on in this course, I will discuss this theory, showing its scientific flaws.

Anaximenes was an associate of Anaximander. He believed that air was the most basic substance in nature. In fact, he believed all things were constructed of air. When air is thinned out, he thought, it grows warm and becomes fire. When air is thickened, he thought, it condenses into liquid and solid matter. We know, of course, that these ideas are wrong. Nevertheless, his attempts to explain all things in nature as being made of a single substance led to one of the most important scientific ideas introduced by the Greeks: the concept of atoms .

Leucippus (lew sip' us) was a Greek scientist who lived perhaps 100 - 150 years after Anaximenes. Although little is known about him, historians believe that he built on the concepts of Anaximenes and proposed that all matter is comprised of little units called “atoms.” As a result, Leucippus is known as the father of atomic theory. The works of his student, Democritus (duh mah' crit us) are much better preserved.

Democritus used the following illustration to communicate his ideas about atoms. Think about walking towards a sandy beach. When you are a long way from the beach, the sand looks like a smooth, yellow blanket. As you get closer to the beach, you might notice that there are bumps and valleys in the sand, but the sand still looks solid. When you reach the beach and actually kneel down and examine the sand, you find that it is not solid at all. Instead, it is composed of tiny particles called “grains.”

Democritus believed that all matter was similar to sand. Even though a piece of wood appears to be solid, it is, in fact, made up of little individual particles which Democritus and his teacher called atoms. Perform the following experiment to see the kind of evidence they proposed for their idea.

EXPERIMENT 1.1
Density in Nature
Supplies

• Vegetable oil
• Water
• Maple or corn syrup
• A grape
• A piece of cork
• An ice cube
• A small rock
• A tall glass

                                                                                
Introduction - The Greek scientists who speculated about atoms used observations such as the ones you will make in this experiment to provide evidence for the existence of atoms.

Procedure :

1. Take the glass and fill it about 1/4 of the way with the vegetable oil.
2. Add an equal amount of water to the glass.
3. Add an equal amount of maple syrup to the glass.
4. Now look at the glass from the side. What do you see? In your laboratory notebook, make a sketch of what you see.
5. Drop the rock, the grape, the ice cube, and the piece of cork into the glass. Now what do you see?
6. Add the rock, grape, ice cube, and cork to the sketch you made in step (D).
7. Clean up the mess and put everything away.
   

What did you see in the experiment? If everything went well, you should have seen that the liquids formed layers in the glass. The vegetable oil formed a layer on top, the water layer was in the middle, and the syrup layer was at the bottom. In addition, the cork should have floated on top of the vegetable oil; the ice cube should have floated on top of the water layer; the grape should have floated on top of the syrup layer, and the rock should have sunk to the bottom of the glass.

How in the world is this experiment evidence for the existence of atoms? Well, according to Democritus, the water, vegetable oil, and syrup are all made of individual particles called atoms. The atoms that make up water, however, are packed together more closely than are those of the vegetable oil. Thus, when the water was poured on the vegetable oil, the atoms in the water were able to squeeze in-between the atoms in the vegetable oil, sinking to the bottom of the glass. In the same way, the atoms in the syrup are more tightly-packed than those in water or vegetable oil, so the syrup's atoms were able to fall in between the atoms of both the vegetable oil and the water and land at the bottom of the glass.

Even solid objects are made up of atoms. Thus, the cork's atoms are packed together very loosely and cannot fit in between the atoms of the vegetable oil. That's why it floats on top of the vegetable oil. The atoms in the ice cube, however, are tightly-packed enough to squeeze in between the atoms of the vegetable oil, but they cannot fit in between the atoms of the water. Thus, the ice cube falls through the vegetable oil but not the water. Similarly, the atoms in the grape are tightly-packed enough to squeeze between the atoms in the vegetable oil and the water, but not the atoms in the syrup. The atoms in the rock, however, are tightly packed enough to squeeze through all of the other atoms, and thus the rock sinks to the bottom.

At this point, I am done discussing the experiment. Now that you know what the experiment shows, you can write a summary in your laboratory notebook. Write a brief description of what you did, followed by a discussion of what you learned. You will need to do each experiment in this way. Once you have done an experiment and read the discussion that relates to it, you then need to write a summary explaining what you did and what you learned. This will help you get the most from your laboratory exercises.

Democritus was not well-received in his time, but later scientists picked up on his ideas and refined them. Today, we know that all matter is made up of atoms. Indeed, today we have a term that describes how tightly atoms are packed in a substance. We call it density . If a substance has a large density, its atoms are tightly-packed. If a substance has a low density, its atoms are less tightly-packed.

Although Democritus was right about all things being comprised of atoms, he was wrong about most of the details regarding what atoms are really like. He believed, for example, that atoms were indestructible. We now know that is wrong. After all, the atomic bomb and nuclear energy are both based on our ability to split atoms. In addition, he thought that the difference between one atom and another was mostly based on shape and size. We now know that atoms are mostly the same shape, and there is a distinct limit to their size. Atoms are so small that roughly 100,000,000,000,000,000,000 atoms are contained in the head of a pin! They are therefore too small for us to see. Nevertheless, we do know that they exist. How do we know they exist if we cannot see them? You will learn about that in a later module of this course.

There was one detail regarding atoms that Democritus was right about. He thought that atoms were in constant motion. For example, if a glass of water is sitting on a table, you might think that the water is not in motion. To some extent, you would be right. After all, the water in the glass stays in the glass, and the glass itself stays on the table. At the same time, however, the atoms that make up the water are in constant motion. They move around within the confines of the glass, rebounding off of the walls of the glass and colliding into each other.

You might find it hard to believe that the atoms within a glass of water are in motion when the water itself is not. However, you might find it a little easier to believe after performing the following experiment.


EXPERIMENT 1.2
Atomic Motion
Supplies :

• Two glass canning jars or peanut butter jars, both the same size
  
• Food coloring, any color
  
• A pan and stove to boil water , and a hotpad to hold the pan
  

Introduction - By seeing how food coloring gets distributed through two jars of water at different temperatures, you will collect evidence for the fact that atoms are in constant motion.

Procedure :

1. Boil some water. You need to boil enough water so that the boiled water will fill one of the jars about halfway.
   
2. Once the water is boiling, take it off of the stove (use the hotpad!) and pour it into one of the jars. Pour in enough water so that the jar is filled about halfway.
   
3. Take the other jar and fill it about halfway with cold water from the tap.
   
4. Wait one minute so that the water in each jar is still.
   
5. Drop a single drop of food coloring into each jar. Observe what happens over the next several minutes. Record in your laboratory notebook the difference between what happened in each jar.
   
6. OPTIONAL: Let the jar with the cold water sit out for a full day. Record what the jar looks like after it has set out for a full day.
   
7. Clean everything up.
   

What did you see in the experiment? If everything went well, you should have seen the drop of food coloring mix rapidly with the hot water, coloring the entire jar of water relatively quickly. In the jar of cold water, however, the food coloring should not have mixed well at all. Why the difference? The answer is the motion of atoms. When a substance is hot, its atoms move faster than when a substance is cold. When you added food coloring to the cold water, then, the atoms in the water collided with the atoms in the food coloring, moving them around. However, since the atoms in the cold water were not moving very quickly, the food coloring did not get moved around much, so it did not mix well with the water. Given enough time, the food coloring will mix well with the water, eventually becoming evenly distributed throughout the jar. When you added the food coloring to the hot water, however, the collisions between the atoms in the food coloring and the atoms in the water were much more violent, because the atoms in the water were moving so much more quickly. This moved the atoms in the food coloring around quite a bit, spreading them out evenly throughout the jar of water in a short time.

In the end, then, even though Democritus was wrong about a great many things, he was right about two important ideas. First, all things are, indeed, made up of atoms. Second, those atoms are in constant motion. Now as I said before, Democritus was not well-received in his time. Most of his fellow scientists rejected his ideas. In fact, the whole idea of the existence of atoms did not gain much popular support among scientists for almost 2,000 years! This just goes to show you that scientists do not always recognize a good idea when they see one. In fact, the history of science is filled with instances of scientists rejecting good ideas in favor of bad ones. You will see more examples of that as you work through the rest of this module.

ON YOUR OWN

1.2 Based on your results in Experiment 1.1, order the items you used in your experiment (water, vegetable oil, the grape, etc.) in terms of increasing density. In other words, list the item with the lowest density first, followed by items of higher and higher density, and end your list with the item of greatest density.

1.3 Do the atoms in an ice cube move faster or slower than the atoms in a glass of water?


Three Other Notable Greek Scientists

Ancient Greece gave us many more notable scientists. It is impossible to discuss them all in a single chapter, but there are three more that simply must be mentioned. The first is Aristotle , who is often called the father of the life sciences. Aristotle was born roughly when Democritus died. He wrote volumes of works on many things, including philosophy, mathematics, logic, and physics. His greatest work, however, was in the study of living things. He was the first to make a large-scale attempt at the classification of animals and plants.

What is classification? Well, classification is a lot like filing papers. Remember, science is a two-part process. A scientist must gather facts and then use those facts to draw conclusions about how the natural world works. As you gather more and more facts, they tend to get hard to use unless they can be ordered in some reasonable, systematic way. That's what classification is all about. By the time of Aristotle, Greek scientists had cataloged many plants and animals, but there were so many that keeping track of them was proving to be very difficult. Aristotle came up with a classification scheme that allowed him to group the known plants and animals into an easy-to-reference system. Because Aristotle was financially supported by Alexander the Great (you should have read about him in history books), he was able to obtain plant and animal samples from all over the known world, adding those to his classification scheme.

Although we do not use Aristotle's particular classification scheme nowadays, all fields of science are still committed to the concept of classification. Indeed, scientists who study living things today are still wrestling with producing the ideal classification system for understanding the life sciences. In a future module of this course, you will get a brief introduction to biological classification. You will then see a lot more of it when you reach biology in high school.

Although Aristotle was known for a great number of wonderful advances in the sciences, he was also responsible for a great deal of nonsense that hampered science for many, many years. For example, he believed that certain living organisms spontaneously formed from non-living substances. This idea was called spontaneous generation .

Spontaneous generation - The idea that living organisms can be spontaneously formed from non-living substances

For example, Aristotle believed that maggots (young flies) spontaneously formed from rotting meat. If you put rotting meat out, it would simply turn into maggots within a few days. He also believed that eels formed spontaneously from the muck at the bottom of a river or pond.
Of course, we now know that spontaneous generation is impossible. In all of our experience, life can only be formed by the reproduction of life. People can have children, animals can have babies, and plants can produce seeds which will grow into new plants. These are some of the ways that life is formed. Life simply cannot be formed from non-living substances. You will learn a lot more of the details regarding the story of spontaneous generation when you take biology. For right now, however, I want to make a point about how science should not be done, and spontaneous generation is the best example to use in order to make this point.

You see, all great scientists make mistakes. Democritus was thousands of years ahead of his time in proposing the existence of atoms, but he was wrong about most of the details regarding atoms. Aristotle made great advances in the study of living things, but he believed in spontaneous generation. Aristotle's mistake was much more damaging to the advancement of science than was Democritus' mistakes. Why? Because Aristotle was respected ! You see, Aristotle was considered (rightly so) to be the greatest scientist of his time. Thus, his ideas (even the wrong ones) were revered for generations ! In fact, the absurd notion of spontaneous generation lasted until 1870 , more than 2,000 years after it was proposed by Aristotle.

Why did the idea of spontaneous generation last for so long? Because it came from Aristotle, and Aristotle was considered a great scientist. In other words, the reputation of the author , not scientific evidence, was the reason people believed in the idea. It took more than 2,000 years for science to show the fallacy of spontaneous generation, simply because people revered Aristotle so much. This is a great example of how science should not be done. Every scientist, no matter how great, will make mistakes. Thus, no scientist's work should be supported because the person was great. It should only be supported because the scientific evidence supports it! Sadly, this lesson has not been learned by many of today's scientists!

The next Greek scientist worthy of note was Archimedes (ark uh me' deez), who lived roughly 100 years after Aristotle. He did great work in mathematics, and he used much of what he discovered in math to advance science. He applied mathematical formulas to explain why certain things happened the way they did. Archimedes was really one of the first scientists to demonstrate how closely mathematics and science are linked.

Archimedes is probably best know for his work with fluids. He was the first to show how you could predict whether or not an object would float in a liquid. His work with liquids led to one of the more entertaining stories in the history of science. The king that Archimedes served, King Hiero, once asked Archimedes to analyze a crown that was given to the king as a gift. The crown was supposed to be made of gold, but the king was skeptical. Archimedes knew how to determine whether or not the crown was made of gold, but the process required him to know the exact amount of space that the crown occupied. This seemed impossible, as the crown was so irregularly-shaped that Archimedes could not find a way to measure it accurately.

Well, one day while taking a bath, Archimedes realized that when an item is immersed in water, it displaces the same amount of water as the space that the item occupies. Thus, all Archimedes had to do was immerse the crown in water and determine how much water it displaced. That would tell him how much space the crown occupied. Archimedes was so excited by this discovery that he grabbed the crown and ran through the streets screaming “Eureka,” which means “I have found it.” There was one embarrassing little problem, however. Archimedes was so excited by his discovery that he forgot to put any clothes on ! In other words, he ran through the streets completely naked!

The last Greek scientist I want to discuss lived about 100 years after Christ's birth. His name was Ptolemy (tall' uh mee), and he studied the heavens. He was the first to try and make a complete description of the planets and stars. He assumed that the earth was at the center of the universe, and that the planets and stars orbited about the earth in a series of circles.

At the time, Ptolemy could explain most of the astronomical data that had been collected using his idea, so it became very popular. Sometimes, his view of the stars and planets is referred to as the Ptolemaic system , in an attempt to honor him. Sometimes, it is referred to as the geocentric system , to emphasize the fact that Ptolemy thought the earth was at the center of the universe.

The Ptolemaic system was considered the correct explanation for the arrangements of planets and stars in space until the 1700's. Thus, it was a popular theory for nearly 1600 years. Once again, however, the reason that the Ptolemaic system was so popular had less to do with the scientific evidence and more to do with other considerations. Like Aristotle, Ptolemy was (rightly) considered a great scientist. As data were collected that contradicted the Ptolemaic system, many scientists ignored it in reverence to Ptolemy.

There was actually another, probably more important reason that the Ptolemaic system became so popular. It became popular because it fit many scientists' preconceived notions of how things ought to be. In the Ptolemaic system, the earth was at the center of the universe and everything revolved around the earth. Since most people believed that the earth was the most important part of the universe, the Ptolemaic system “made sense.”

Sadly, the most ardent support for the Ptolemaic system came from the church. As more and more scientific evidence came pouring in indicating severe flaws in the Ptolemaic system, the church tried to resist any movement away from it. After all, the church reasoned, since God created man, the earth must be the most important thing in the universe, so it must be at the very center, and everything else must travel around it, just as Ptolemy said. Now, of course, nowhere in the Bible is such a thing written, but that didn't stop the church from believing in it!

In the end, it took hundreds of years of scientific data (and a few people thrown out of the church) before the church was convinced to give up on the Ptolemaic system. Unfortunately, by that time, the damage had been done. The church became viewed as antagonistic to science, and some people today still hold that view. This is unfortunate because, as you will see in later sections of this module, Christianity is a friend to science. Most of the great scientists in history were Christians, and it was their Christianity that many credited for their scientific achievements. Nevertheless, because the church was unwilling to give up on the Ptolemaic system when the scientific evidence was overwhelming, many still see Christianity as an enemy of science. That's too bad.

So this little episode from history shows us another way that science should not be done. You should not hold fast to an idea simply because it fits with your preconceived notions. Science is built on data, not a person's beliefs. The acceptance or rejection of a scientific proposition, then, should rest solely on the data, nothing more. Today, there is a theory called evolution . It is popular among scientists not because there is a lot of evidence for it, but because it fits in with many scientists' preconceived notions. As you will learn in a later module, very little evidence exists for the theory of evolution, and much evidence exists against it. Nevertheless, it is still a prevalent theory because many people like the fact that it tries to explain the existence of life without ever referring to God. As a result, they believe the theory in spite of the evidence. Unfortunately, these people have not learned from the history of science. The history of science teaches us over and over again that believing in an idea because of preconceived notions hurts the cause of science; it does not help it!


ON YOUR OWN

1.4 Dr. Steven Hawking is one of the most brilliant scientists of the decade. He believes in a theory called “the big bang.” This theory tries to describe how the universe was formed. If your friend tells you that you should believe in the big bang because Dr. Hawking is so smart and he believes in it, what famous example from the history of science should you tell to your friend?

1.5 What episode from the history of science tells us that we need to leave our personal biases behind when we do science?

The Progress of Science Stalls For a While (From 500 A.D. to 1400 A.D.)

From the time of the first three Greek scientists (Thales, Anaximander, and Anaximenes) until about 400-500 A.D., science progressed at a dizzying rate. Many scientists proposed many ideas trying to explain the natural world. Those ideas were debated and compared to observations. Great houses of learning were established to foster scientific inquiry. Works like those of Aristotle and Ptolemy became the guiding principles behind the progress of science.

After the first few centuries A.D., however, the progress of science stalled dramatically. By that time, the Roman Empire had a great deal of influence throughout the known world, and Rome had a distinct dislike of science. The Roman Empire did not mind the inventions, especially those that made work more productive, but it had little use for the practice of explaining the world around us. As a result, science was actively discouraged in most parts of the world.

Alchemy is one of the best examples of what passed for science during this time period. Alchemists mostly wanted to find a means by which lead (or other inexpensive substances) could be transformed into gold (or other precious substances). You see, many people had observed the fact that when you mix certain substances together, they change into other substances. Perform the following experiment to see what I mean.

EXPERIMENT 1.3
A Chemical Reaction
Supplies :

• A plastic, 2-liter bottle
  
• A balloon (6-9 inch round balloons work best.)
  
• Clear vinegar
  
• Baking soda
  
• A funnel or butter knife
  
• A few leaves of red (sometimes called purple) cabbage
  
• A saucepan
  
• A stove
  
• Measuring cups
  
• A few ice cubes
  

Introduction – During the Dark Ages, people observed that mixing several substances together could cause amazing results. This experiment shows you some of what can happen when the right substances are mixed together.

Procedure :

1. Put about 2 cups of water in the saucepan and add several leaves of red cabbage. Put it on a stove burner and heat it so that the water boils.
   
2. While you are waiting on the water to boil, take the balloon and put baking soda in it. You want to have about 2 tablespoons of baking soda in the balloon. The best way to do this, of course, is to use a funnel. If you do not have a funnel, try picking up the baking soda on the flat of a butter knife, pushing the knife into the balloon's opening, and then tipping the knife so that the baking soda spills into the balloon. It is tedious, but it will work.
   
3. Once the balloon has about 2 tablespoons of baking soda in it, pour 3/4 of a cup of clear vinegar into the 2-liter bottle.
   
4. Once the water in the saucepan reaches boiling, remove it from the heat. Allow the liquid in the pan to cool by adding some ice. The liquid should have a blue or pink color now.
   
5. Add ½ of a cup of the liquid to the 2-liter bottle.
   
6. Attach the balloon to the opening of the 2-liter bottle by stretching the balloon's opening over the lip of the bottle. In the end, your experiment should look like this:
   
7. Once you are ready, lift the balloon so that the baking soda falls into the vinegar. Write down what you see in your laboratory notebook.
   
8. Clean everything up and put it all away.
   

What did you see in the experiment? When the baking soda hit the vinegar, the mixture began to bubble and fizz, and the balloon began to inflate. At the same time, you should have noticed a color change. The mixture should have turned from a pinkish color to a bluish color. What happened? Well, you witnessed the effect of a chemical reaction . In a chemical reaction, one or more substances interact to form one or more new substances.

In your experiment, there were actually 2 chemical reactions going on. The first occurred when vinegar was mixed with baking soda. Those two substances interacted, forming two new substances: carbon dioxide and water. The carbon dioxide, which is a gas, bubbled out of the vinegar and into the balloon, filling up the balloon. The second reaction occurred as the vinegar was being used up in the first reaction. A substance in red cabbage, anthocyanin (an tho sigh' an un), interacts with vinegar to form a pink color. As the vinegar disappeared in the first reaction, the anthocyanin no longer had vinegar to interact with, so the pink color went away and was replaced by a blue color.

Alchemists in the Dark Ages saw changes like this and decided that if they were just able to find the right recipe, they could mix lead with several other substances and make gold. Of course, we now know that this is impossible, because we know that there are severe limitations on how much one substance can change in a chemical reaction. You will learn all about that when you take chemistry. The alchemists of the Dark Ages didn't know this, however, so they strove to mix substance after substance with lead, hoping one day to find that “magic” mixture which would turn lead into gold.

As alchemists began mixing and recording, many interesting things were observed. These observations were written down, and, every once in a while, one of the mixtures would form some useful substance. The recipe to make this useful substance would then be recorded, and the alchemist would proceed on to the next mixture. Like ancient Egyptian medicine, then, the alchemists (and most “scientists” of the Dark Ages) really just learned things by trial and error. They never tried to take their observations and draw conclusions about how the natural world works. Instead, they were content to just write down their observations and move on to the next experiment, searching for the next useful substance they could make.

Interestingly enough, even though the ideas of Rome held great sway in most of the known world, the Roman Empire itself began to crumble. As that happened, trade and large-scale communication became harder and harder. Since science thrives on the free exchange of ideas from one scientist to another, this put another roadblock in the way of scientific progress. Many historians refer to this period as the Dark Ages , because compared to the previous time period in history as well as the next time period in history, little was learned.

So here we find another lesson that we can learn from the history of science. Scientific progress depends not only on scientists, but it also depends on government and culture. Since the Romans actively discouraged science and concentrated on inventions, the progress of science slowed. Since the crumbling government caused trade and communications to become more difficult, scientific progress slowed even more. For science to proceed, then, the government and the culture must support it.

Although the progress of science slowed during this period, there are a few things worth noting. Most of the knowledge that had accumulated up to this point was carefully preserved by Roman Catholic monks. These monks, and Christians in general, believed that God had revealed Himself to His creation in two ways: through scripture and through nature. Thus, these monks were committed to preserving both means of revelation. They copied and re-copied scripture so as to preserve it for coming generations. They also did the same with the accumulated scientific knowledge of the time. They created large volumes of scientific observations and speculations which came to be known as encyclopedias . These encyclopedias, with their vast accumulation of data and ideas, were one of the main reasons that science was able to flourish in the next period of history.

Another thing worth noting about this period is the fact that although real science stalled dramatically, there were still a lot of people making observations and inventing things. Both Arabs and Chinese during this time period were involved in making careful studies of the heavens. They made observations that were much more detailed and precise than those of the Greek scientists that came before them. Even though there were very few attempts to explain what those data meant , at least the data were being collected, and they would be used by later scientists to draw great conclusions about the world around us.

For example, Chinese records from 1054 A.D. include detailed observations of a phenomenon that the Chinese observers did not understand. Although they did not understand it, they recorded their observations in great detail, and modern scientists were able to use those observations to determine that the Chinese had seen a supernova , which is essentially the explosion of a star. The observations were so detailed that modern scientists were able to determine where this explosion happened, and when they looked at that part of space, they found a cloud of dust and gas which is called a nebula . Based on these facts, modern scientists now believe that a nebula is the remains of a star which has exploded.


Once again, then, we come to another lesson in the history of science. Science progresses by building on the works of previous scientists. Had the monks of this time period not cataloged and preserved the thoughts and observations of the scientists that had come before them, the scientists that came after them would not have had a foundation upon which to build. Had the Chinese not recorded such detailed observations of the night sky, modern scientists might still not know where a nebula comes from. Thus, in order for science to advance, we must study and preserve the works of the scientists that come before us. As more and more scientific knowledge is accumulated, this becomes a more and more important task.

Another thing worth noting about this time period is that the Christian church (mostly the Roman Catholic church) was instrumental in continuing the progress of medical treatment. The works of previous scientists were studied in monasteries, because Christians believed it was their duty to aid and comfort the sick. Thus, the medical advances that had been made up to this period in history were preserved and practiced throughout the Dark Ages. In addition, although no real understanding about the human body emerged, more trial-and-error medicine such as that practiced by the ancient Egyptians did lead to modest advances in the treatment of illness.


ON YOUR OWN

1.6 A great many scientists today worry that most of the younger generation does not appreciate science very much. There are those that worry about the future of science when the younger generation grows up. Although it is true that most young people today don't care for or about science, there are some who do. They will obviously become the scientists of the future. Since there will always be at least a few people who are interested in science, why are today's scientists so worried about the future of science?


Science Begins To Pick Up Some Speed Again (1000 A.D. – 1500 A.D.)

Towards the end of the Dark Ages, real science slowly began to emerge again, thanks mostly to the Roman Catholic church. Remember, science slowed considerably at the beginning of the Dark Ages due to the influence of the Roman Empire, which had little regard for real science. One of the reasons it held science in such low esteem was due to the predominate religion of the Roman Empire. The Romans believed in many gods. These gods roamed the universe, alternately torturing or helping humans, depending on the gods' whims. With such a religion, there was no reason to believe that the natural world could be explained. After all, the gods' actions were random, based on whims. Thus, the Romans reasoned, the natural world itself (which was the creation of the gods) must also be rather random. As a result, Romans believed that the natural world simply could not be explained.

By A.D. 1000, however, Christian scholars began realizing that their beliefs promoted a completely different way of looking at the world around them. They believed in a single God who created the universe according to His laws. Since they believed that God's laws never changed, they realized that the natural laws which God set into motion should also never change. As a result, the way that the natural world worked could be explained, as long as scientists could discover the natural laws which God set into motion.

It might seem painfully obvious to you that the natural world must obey certain laws. However, that kind of thinking was relatively revolutionary at the end of the Dark Ages. Now realize that this kind of thinking wasn't really new . It was just different than the predominate idea of the day. After all, the Greek scientists like Aristotle and Ptolemy also believed that the natural world could be explained by laws which did not change. Nevertheless, their thinking was mostly ignored during the Dark Ages, due to the influence of Roman thought.

Perhaps the most important figure in this time period was Robert Grosseteste (grow' suh test ee). Grosseteste was a bishop in the Roman Catholic church in the early 1200's A.D., and he was deeply committed to the idea that the secrets of the natural world could be learned by discovering the laws that God had set in motion. He taught that the purpose of inquiry was not to come up with great inventions, but instead to learn the reasons behind the facts. In other words, he wanted to explain why things happened the way that they did. That's the essence of science.

Grosseteste taught that a scientist should make observations and then come up with a tentative explanation for why the observed events happened. The scientist should then come up with experiments that would test his explanation. If the results of the experiments confirmed the explanation, then the explanation might be considered reliable. If the experiments contradicted the explanation, then the explanation must be wrong.

As you will learn in the next chapter, this is essentially the method that we use today in modern science. Thus, Grosseteste is often called the father of the scientific method, because he was the first to explain and use it. Grosseteste applied his scientific method to the problem of explaining the rainbow. Although Grosseteste never developed a satisfactory explanation for the rainbow, a Roman Catholic priest who lived roughly 50 years later, Dietrich Von Freiberg , built on Grosseteste's work and was able to offer an explanation for why a rainbow appears in the sky. Because of that, Von Freiberg is often called “the priest who solved the mystery of the rainbow.” Next year (in physical science), you will learn about how a rainbow forms.

Although Grosseteste is considered the father of the scientific method, his pupil, Roger Bacon , is more famous and is sometimes given that title in error. Bacon staunchly advocated the use of his teacher's scientific method. He tried over and over again to use science to break the shackles of superstition. For example, conventional wisdom in Bacon's day was that a diamond could be broken only by the application of goat's blood. He proposed experiments that, when performed, showed that goat's blood had no effect whatsoever on diamonds.

Bacon also had a strong belief that science could be used to support the reality of Christianity. A devout theologian, Bacon believed that the more man learned about science, the more he would learn about God. In addition, Bacon seemed to see the potential of science when few others did. In his writings, he predicted that science would bring about marvels such as flying machines, explosives, submarines, and worldwide travel. People laughed at his ideas back then, but historians today marvel at his insight.

Roughly 70 years after Bacon (in the early 1300's), another important figure, Thomas Bradwardine (brad war' deen), emerged on the scene. Bradwardine was a bishop in the Roman Catholic church, and his work was important on two levels. First and foremost, Bradwardine was a theologian who questioned much of the Roman Catholic church's teachings. Most church historians consider him the first Reformer, because he emphasized salvation through faith and the grace of God. The more well-known reformers (Luther and Calvin) were heavily influenced by Bradwardine's work.

Not only was Bradwardine an important figure in church history, he was also important in the development of modern science. Bradwardine was the first scientist to examine many of Aristotle's ideas critically. He found most of them lacking. He concentrated on understanding motion. He wanted to know why things moved, what kept them moving, and what made them stop. He applied mathematics to his study of motion and actually developed equations which tried to describe the details of speed, distance traveled, and so forth. Using mathematics and experiments, he was able to show that most of what Aristotle said about motion was wrong. Although it took nearly 300 more years for science to throw away Aristotle's ideas about motion, it never would have happened without Bradwardine's work.

The last great scientist of this era was Nicholas of Cusa . He was also a priest in the Roman Catholic church in the mid-1400's and became an influential leader in the church towards the end of his life. He was particularly interested in the idea that God was infinite. Because he wanted to learn more about God's infinite nature, he studied the planets and the stars, thinking that they were probably the largest (and thus closest to infinite) things that he could study. His studies of the planets were revolutionary because he was the first to break from Ptolemy's geocentric view. He (correctly) believed that the earth spins while it travels around the sun. This was in direct disagreement with Ptolemy's ideas, and it laid the groundwork for the scientific revolution that would take place two hundred years later.

Before I end this section, I want to make sure that you have picked up on something. Notice that each of the great scientists of this era were devout Christians. In fact, they were all clergy (priests, bishops, etc.) of the Roman Catholic church. As you read through the rest of this module, you will notice that, with a few notable exceptions, most of the great scientists from the Dark Ages to modern times were devoted Christians. Once again, that's because the Christian worldview is a perfect fit with science. Science is based on the notion that the world works according to rational laws that do not change. Since Christians believe in a rational Creator whose laws do not change, science and Christianity work very well together.

That last statement surprises some people. Some people actually believe that science and Christianity are at odds with one another. Unfortunately, that myth has developed recently, mostly because the majority of scientists today are not Christian. However, even a quick look at science history tells us that without Christianity, science would never have gotten out of the Dark Ages. The Christian worldview was essential in turning trial-and-error based observations into true science. The more you learn about the history of science, the more you will see that this is the case!

ON YOUR OWN

1.7 Some historians call Grosseteste the first modern scientist. Why does Grosseteste deserve that honor?


The Renaissance: The “Golden Age” of Science (1500 A.D. – 1660 A.D.)

The 16 ^th and 17 ^th centuries (1500 A.D. to 1700 A.D.) were incredibly exciting in the history of science. The excitement began in 1543, when two very important works were published. The first (and most celebrated today) was published by Nicholas Copernicus . It was a book that laid out his idea about the earth, sun, and the nearby planets. Like Nicholas of Cusa, Copernicus believed that Ptolemy's view of the universe was wrong. Rather than placing the earth at the center of everything and believing that the sun and all of the planets traveled around the earth, Copernicus placed the sun at the center of everything and assumed that all of the planets (including the earth) traveled around the sun. This view was called the heliocentric (he' lee oh sen trik) system , because “Helios” is the Greek god of the sun . Sometimes, however, it is called the Copernican system , in honor of Copernicus.


Copernicus had actually completed his studies of the planets and written his book nearly 13 years before it was published. However, Copernicus delayed its publication because the Roman Catholic church disagreed with his heliocentric system. This fact was a little ironic, as Copernicus himself was part of the clergy of the church and had actually done his work at the request of the pope, who was the head of the Roman Catholic church! Nevertheless, the Roman Catholic church publicly denounced Copernicus' work and put his book on their list of prohibited reading. As I mentioned in a previous section, the church did this not because of science, but because of preconceived notions. The church liked the idea of the earth being at the center of everything, and they therefore did not want to give up Ptolemy's geocentric view.

The other important work published in 1543 was written by a doctor named Andreas Vesalius (vuh sal' ee us). It was a book that tried to show all of the details of the human body. It contained incredibly detailed and amazingly accurate illustrations of the organs, muscles, and skeleton of the human body. This was the first book that illustrated all of the “insides” of the human body, and it revolutionized how medicine was taught.

Although the importance of Vesalius' book was recognized right away, it took longer for people to recognize the importance of Copernicus' work. The first reason, of course, was the fact that the Roman Catholic church banned the book. The second reason was that although Copernicus had the right idea, he had very little data to back it up. Copernicus promoted his heliocentric system not because he had made a lot of observations that supported this view, but because he knew that there was a lot of evidence against Ptolemy's geocentric view. Copernicus also thought a heliocentric view was easier to understand and describe, so he was attracted to it for that reason as well.

Copernicus' heliocentric view became more and more accepted as more and more evidence for it was compiled. One of the most important compilers of such evidence was Johannes Kepler . Kepler began making observations of the heavens in the late 1500's. He desperately wanted to be a minister, but he had terrible financial problems that forced him to accept a job as a teacher instead. While he taught, he studied the heavens, hoping that his observations would bring glory to God. In a particularly revealing letter, he wrote, “I wanted to become a theologian. For a long time, I was restless. Now, however, behold how through my effort God is being celebrated in astronomy.”

Kepler made detailed observations of the planets. His observations were so detailed that he was able to deduce the basic orbits that the planets used to travel around the sun. He was even able to describe these orbits mathematically. His mathematical equations became known as “Kepler's Laws,” and they became one of the most powerful arguments for the heliocentric system. Kepler's observations of the planets were so detailed and precise, that he was able to determine something very interesting about the planets. His data showed that the planets don't really travel around the sun in circles. They actually travel around the sun following an oval pattern, which mathematicians call an “ellipse.” Perform the following “experiment” to learn about how the planets really travel around the sun.

“EXPERIMENT” 1.4
Mapping the Paths of the Planets

Supplies :

Both of the drawings are ellipses. An ellipse is defined by two points called foci (the singular of which is focus ). In your “experiment,” the foci were the two pins. If you were to take any point on the first ellipse that you drew and measure the distance from that point to the holes that marks where each pin was, the sum of those two distances would be 5 inches. That's the property of an ellipse. The sum of the distances from any point on the ellipse to each of the foci is always the same. On the second ellipse you drew, the sum of those distances would be 8 inches, because the string was longer when you drew the second ellipse.

Now don't worry if you do not completely understand ellipses. The main point I want you to understand is the difference between the two ellipses you drew. The second one is much more circular than the first, isn't it? That's because the string was longer the second time. The ellipses in which the planets travel around the sun are very nearly circular. Thus, they are much more like the second ellipse than the first. Well, if the second ellipse you drew is like the orbit of a planet, where is the sun? The sun is at one of the two foci. In the end then, the planets do not travel around the sun in perfectly circular orbits. They travel in ellipses. Also, the sun is not exactly in the center of the ellipse. Instead, it is one of the foci of the ellipse.

Other powerful evidence for the heliocentric view came from a scientist named Galileo (gal uh lay' oh) Galilei (gal uh lay'), who is usually referred to by only his first name. Galileo was a well-known, well-respected scientist for many reasons. He did detailed experiments about motion, confirming the work of Bradwardine and showing the flaws in Aristotle's thinking. Galileo started compiling evidence for the heliocentric system when he “invented” the telescope in 1609. I put “invented” in quotes because, in fact, he was not the first to build a telescope. Galileo was told about an invention that was displayed at an exposition in Venice. This invention was called the “optical tube.” From the description he heard, he was able to determine how this invention worked and quickly built one for himself, claiming to be the first to invent it. The name of the true first inventor has been lost in history, and Galileo has been given the credit, even though he actually stole the idea.

Although Galileo came by his telescope in a less than honest way, the data that he collected with his telescope was invaluable to the advancement of the heliocentric system. He was able to show that the planets do not shine on their own. He demonstrated that the planets appear as lights in the night sky simply because they reflect the light of the sun. This fact and many others that he collected with the telescope made it clear that the heliocentric view was superior to the geocentric view. Unfortunately, the Roman Catholic church would not let go of the geocentric view, and it officially demanded that Galileo hold to the geocentric view in all of his writings. Because Galileo was a devout Christian, he obeyed the Roman Catholic church and stopped officially promoting the heliocentric system. Nevertheless, he kept collecting data. Well after his death, Galileo's data (along with Kepler's laws) simply proved too powerful for the church to neglect, and the heliocentric system was eventually accepted as the correct view of the heavens.

Even though the advances in understanding the heavens take center stage in the history of this period, many other scientific advances took place as well. Blaise (blaze) Pascal (pass' kal) lived in the mid-1600's. He was a brilliant philosopher, mathematician, and scientist. If you have studied Christian apologetics at all, you might remember him as the author of “Pascal's wager.” This argument presents a person's worldview in terms of a bet. He then argues convincingly that Christianity is, by far, the best bet.

In addition to his philosophy, Pascal is also well remembered for his work as a mathematician and scientist. In math, he made several advances in the understanding of both geometry and algebra. In science, he spent an enormous amount of time studying the air and liquids. He demonstrated that the air we breathe exerts pressure on everything, an effect we call atmospheric pressure today. In his studies of fluids, he demonstrated a law which we now call “Pascal's Law.” The science behind that law allowed us to develop hydraulic lifts, like the lift that a mechanic uses to raise a car so that the mechanic can get underneath it.


ON YOUR OWN

1.8 Galileo faced a very difficult decision in his life. He was convinced by science that the heliocentric system was correct. Nevertheless, his church said that it was wrong and threatened to throw him out of the church if he didn't recant his belief in the heliocentric system. Galileo, in obedience to his church, agreed to publicly recant his belief, even though he knew it was right. Did Galileo make the right choice, or should he have stayed true to his science and been thrown out of the church?


The Era of Newton (1660 A.D. – 1734 A.D.)

Although the Renaissance is often called the “golden age” of science, I personally think that science enjoyed its greatest advancement during the time of Sir Isaac Newton . As is the case with most of the great scientists of the past, Newton was a devout Christian. He studied science specifically as a means of learning more about God, but he never forgot that the best way to learn about God was by thorough Bible study. He wrote many commentaries on the Bible, concentrating on prophecy. He was particularly drawn to the book of Daniel. In his later years, he spent a lot more time writing about the book of Daniel than he did writing about science.

To call Sir Isaac Newton brilliant would be an understatement. In his short lifetime, Newton laid down three laws of motion that still guide the science of physics today. He formulated a universal law of gravitation, which is also still used to this day. He developed the mathematical field of calculus, which is an essential tool in many fields of science. It is little wonder that most science historians consider Sir Isaac Newton to be the single greatest scientist in the history of the world.

Newton wrote most of his revolutionary scientific work in a three-volume set call the Principia (prin sip' ee ah). In the first volume, Newton laid down three laws of motion. You will learn about these laws next year when you take physical science. In formulating these laws, Newton made a direct link between mathematics and science. In essence, Newton proposed that a scientific law was useless if it could not be used to develop a mathematical equation which would describe some aspect of nature. The deep link that Newton established between science and math resulted in a major breakthrough. Although many scientists in the past had used mathematics to analyze a scientific problem, Newton was the first to establish a deep link between the two. This link helped turn scientific research into a detailed, rigorous field of study.

In the second volume of the Principia , Newton built on the work of Pascal and added many details to the understanding of the motion of fluids. In the third volume, Newton laid down his universal law of gravitation. The term “universal” has a specific meaning here. You see, scientists in Newton's day thought that the reason an object falls when it is dropped is due to one physical process and that the reason the planets moved in the sky is due to a completely different process. Newton showed that this was not the case. In volume three of the Principia , Newton used detailed experiments to show that gravity was the cause of both effects. The same gravity that attracts objects to the earth (making them fall) also attracts planets to one another, keeping them in their orbits around the sun. In addition to his experimental results, Newton had (of course) developed detailed mathematical equations that describe gravity. Those mathematical equations are still considered accurate to this day. The third volume of the Principia essentially was the death blow to the geocentric view of the heavens.

Although Newton took center stage during this time period, there were other great scientists who brought about other great advances as well. Robert Boyle , the founder of modern chemistry, was a contemporary of Newton. He did many experiments with gases, formulating laws that are still used today in chemistry. In fact, when you take chemistry in high school, you will undoubtedly learn about Boyle's Laws. Boyle was also a dedicated Christian, who often wrote sermons using nature to give glory to God. His last words to the Royal Society (a group of scientists in England) were “Remember to give glory to the One who authored nature.” Unfortunately, those words were eventually forgotten.

Another notable scientist from this period was Antoni (an' ton ee) van Leeuwenhoek (lew' en hook). Although not educated as a scientist, Leeuwenhoek revolutionized the study of life by building the first microscope . This microscope allowed him to see a world that had been completely invisible up to this point. His microscope allowed him to discover many tiny (microscopic) life forms, including bacteria. The existence of these life forms helped scientists explain many things that had been, up to this point, complete mysteries. Like Boyle, Leeuwenhoek tried to glorify God in all of his scientific work. To him, the existence of a microscopic world was just one more testimony to the grandeur of Creation.


ON YOUR OWN

1.9 Many students think that mathematics is too difficult to learn. In order to try and teach science to such students, there are many science textbooks written today which do not use mathematics at all. What would Newton say about such textbooks?



The “Enlightenment” and the Industrial Revolution (1735 A.D. – 1819 A.D.)

This period in history marks the beginning of a change in the underlying assumptions of science. A philosopher of the time, Immanuel Kant, used the term Enlightenment to describe this change. Unfortunately, the change was only partially beneficial to the progress of science, so I always put the term in quotes, because the change that began in this period was only partially enlightened.

What is this change to which I refer? Well, up to this point in history, God was at the center of virtually all science that was performed. As you can see from the previous sections, most of the great scientists up to this point in history were devout Christians. Since most of the progress in science was being made by Christians, science had a very Christian flavor to it. You could hardly find a scientific book or paper written that did not mention God reverently throughout the text. Prayer was at the forefront of most scientific meetings and assemblies. Christianity was the basis of most scientific education. At this point in human history, that began to change.

What caused this change? Ironically, the great advances in science up to this point in history were indirectly the cause. You see, the advances made in science from the Dark Ages up to this point in history were the result of scientists ignoring the teachings of Ptolemy, Aristotle, and the other scientists whose works had dominated science for so long. As time went on, the scientific community began to learn that scientists should not just accept the teachings of former scientists. Instead, they realized that all scientists make mistakes, and therefore everyone's work must be examined critically. In the end, then, science stopped relying on the authority of past scientists and began relying on experiments and data.

That's the good part of the change that occurred during the enlightenment. Scientists stopped referring to the authority of past scientists and started examining all scientific works critically. As I have already pointed out in a previous section, that's the way science should be done. Unfortunately, as science began to ignore the authority of past scientists, it also began to ignore the authority of the Bible. That's the bad part of the change which occurred during the “enlightenment.” Despite the fact that a Biblical worldview had brought about great advances in science, some scientists began to question the truth of the Bible.

Remember, up to this point in history almost all of the great scientists were devout Christians. As a result, it was difficult to find any work of science that did not mention God with great respect and reverence. During the “enlightenment,” this slowly began to change. Of course, the change was not abrupt. Many scientists during this time period and beyond were devout Christians, and God was still mentioned in many scientific works. However, as time went on, fewer and fewer references to God could be found in the works of science.

Although this period can be thought of as the beginning of science's departure from a Biblical worldview, it is marked in history by the work of a devout Christian, Carrolus (care' uh lus) Linnaeus (lih nay' us). In 1735, Linnaeus published a book in which he tried to classify all living creatures that had been studied. This work is often