Apologia General Science Sample

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Apologia General Science Sample

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 :

Take the glass and fill it about 1/4 of the way with the vegetable oil.

Add an equal amount of water to the glass.

Add an equal amount of maple syrup to the glass.

Now look at the glass from the side. What do you see? In your laboratory notebook, make a sketch of what you see.

Drop the rock, the grape, the ice cube, and the piece of cork into the glass. Now what do you see? Add the rock, grape, ice cube, and cork to the sketch you made in step (D).

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.