Apologia Physical Science Sample

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Apologia Physical Science Sample


Module #1: The Basics

Introduction

In this course, you are going to learn a lot about the world around you and the universe that it is in. We will study things as familiar as the air around you and others as mysterious as radioactivity and distant galaxies. We will learn how to use geology to look into earth's past as well as how to use meteorology and astrophysics to predict certain aspects of its future. The study of these topics and many others like them are all a part of what we call physical science.

In order to make sure that we are both starting on the "same page," I need to discuss some basic concepts with you. It is quite possible that you have learned some (or all) of this before, but it is necessary that we cover the basics before we try and do anything in depth. Thus, even if some of the topics I cover sound familiar, please read this module thoroughly, so that you will not get lost in a later module. In fact, many of the subjects that I will cover in later modules are probably familiar to you on one level or another. After all, most students your age know something about fossils, the construction of our planet, weather, and astronomy. Nevertheless, I can almost guarantee you that you have not learned these subjects at the depth which I will discuss them in this course. So, despite how much you might think you know on a given topic, please read the material I present to you carefully. I doubt that you will be disappointed.

If, on the other hand, all of this is completely new to you, don't worry about it. As long as you read the material carefully, perform the experiments thoroughly, and really think about what you learning, everything will be fine. Although this course might not be easy for you, there are very few things in life that are both easy and worthwhile. I promise you that if you work at learning this course, you will gain a great deal of knowledge, a solid sense of accomplishment, and a grand appreciation for the wonder of God's Creation!

Atoms and Molecules

In this course, I am going to try to illustrate as many concepts as possible with experiments. Hopefully, the "hands on" experience will help bring those concepts home better than any discussion could. In some cases, of course, this will not be possible, so we will have to make due with words and pictures. To start our discussion of atoms and molecules, I want you to perform the following experiment.

EXPERIMENT 1.1

Atoms and Molecules

Supplies:

A small glass, like a juice glass
Baking soda
Tap water
A 9-Volt battery (the kind that goes in a radio, smoke detector, or toy. DO NOT use an electrical outlet, as it will most likely kill you! A 1.5 Volt flashlight battery will not work.)
Two 9-inch pieces of insulated wire. The wire itself must be copper.
A pair of scissors
Tape (preferably electrical tape, but cellophane or masking tape will work)

Introduction - Atoms and molecules make up everything that surrounds us. Individually, they are simply too small to see. However, you can distinguish between different kinds of atoms and different kinds of molecules by examining the substances that they make up, as well as how those substances change. In this experiment, we will observe molecules changing into atoms and atoms changing into molecules. By observing these changes, you will learn about the difference between atoms and molecules.

Procedure:

A. Fill your small glass 3/4 full of tap water.

B. Add a teaspoon of baking soda and stir vigorously.

C. Use your scissors to strip about a quarter inch of insulation off both ends of each wire. The best way to do this is to put the wire in your scissors and squeeze the scissors gently. You should feel an increase in resistance as the scissors begin to touch the wire. Squeeze the scissors until you feel that resistance and then back off. Continue squeezing and backing off as you slowly turn the wire round and round. Be careful. You can cut yourself if you are not paying proper attention! You will eventually have a cut that goes through the insulation all the way around the wire. At that point, you can simply pull the insulation off. It will take some practice to get this right, but you can do it. Make sure that there is at least a quarter inch of bare wire sticking out of both ends of wire.

D. Once you have stripped the insulation off both ends of each wire, connect the end of one wire to one of the two terminals on the battery. Do this by laying the wire over the terminal and then pressing it down. Secure it to the terminal with a piece of tape. It need not look pretty, but it needs to be solidly touching one terminal and not in contact with the other terminal.

E. Repeat step D with the other wire and the other battery terminal. Now you have two wires attached to the battery, one at each terminal. Do not allow the bare ends of these wires to touch each other!

F. Now immerse the wires in the baking soda/water solution that is in your small glass so that the bare end of each wire is completely submerged. It doesn't really matter how much of the insulated portion of the wire is immersed, just make sure that all of the bare end of each wire is fully submerged.

G. Look at the bare ends of the wires as they are submerged in the baking soda/water solution. What do you see? Well, if you set everything up right, you should see bubbles coming from both ends. If you don't see bubbles, the most likely problem is that you do not have good contact between the wires and the battery terminals. Try pressing the ends of the wire hard against the terminals they are taped to. If you then see bubbles coming from the submerged ends of the wire, you know that electrical contact is your problem. If not, your battery might be dead. Try another one.

H. Once you get things working, spend some time observing what's going on. Notice that bubbles are forming on both wires. That's an important point which should be written in your laboratory notebook.

I. Allow the experiment to run for about ten minutes. After that time, pull the wires out of the solution and look at the bare ends. What do you see? Well, one of the wires should really look no different than when you started. What about the end of the other wire? It should now be a different color. What color is it? Write that color down in your notebook.

J. If you really let the experiment run for 10 minutes, it's very possible that your solution became slightly colored. Write in your notebook whether or not that did happen and what color, if any, the solution became.

K. Looking at the wire that changed color, trace it back to the battery and determine which terminal (positive or negative) it was attached to. Write that in your laboratory notebook as well.

L. Clean up: Disconnect the wires from the battery, discard the solution, and wash the glass thoroughly. Put everything away.

Now, to understand what went on in the experiment, you need a little background information. Everything that you see around you is made up of tiny little units called atoms.

Atom - The smallest stable unit of matter in Creation

Atoms are so small that you cannot see them at all. They are so small, in fact, that roughly 100,000,000,000,000,000,000 atoms are contained in the head of a pin. If we can't see them, then how do we know that they exist? Well, lots of experiments have been done that can only be explained if you assume that atoms exist; thus, there is a lot of indirect evidence that atoms exist. All of this indirect evidence leads us to believe that atoms are, indeed, real.

When you stripped the insulation off the ends of each wire, you saw the familiar red-orange color of copper wire. Well, it turns out that copper is a type of atom. Thus, the copper that you observed in the wire was really just a bunch of copper atoms lumped together. You couldn't see the individual atoms, but when billions of billions of billions of them are put together, you can see the substance that they make. When you have billions of billions of billions of copper atoms, you get the flexible, electricity-conducting, red-orange metal called copper.

Now we currently know that there are about 109 basic kinds of atoms in Creation. This number increases as time goes on, because every once in a while scientists will discover a new kind of atom. In a few years, then, the number of basic kinds of atoms in Creation will probably be a little larger. That's why I say "about" 109 different kinds of atoms in Creation.

If this were the end of the story, Creation would be pretty boring. After all, if everything that you see is made up of atoms, and if there are only about 109 different kinds of atoms in Creation, then there are only 109 different substances in Creation, right? Of course not! Although God used atoms as the basic building blocks of Creation, He designed those atoms to link together to form larger building blocks called molecules.

Molecule - Two or more atoms linked together to make a substance with unique properties


It turns out that the water that you used in your experiment is made up of molecules. Although molecules are bigger than atoms, you still cannot really see them. Thus, the water that you see is made up of billions of billions of billions of water molecules, just like the copper wire is made up of billions of billions of billions of atoms of copper. A water molecule is formed when an oxygen atom links together with two hydrogen atoms. When these atoms link together in a very specific way, the result is a water molecule.

Now we are ready to really discuss the results of the experiment. When you filled the glass with water, you were filling it with billions of billion of billions of water molecules. When you placed the wires (which were connected to the battery) into the water, the electricity from the battery began flowing through the water. When this happened, the energy from the electricity flow actually broke some of the water molecules down into hydrogen and oxygen, which began bubbling out of the water, because hydrogen and oxygen are gasses!

This is an excellent illustration of atoms and molecules. Each water molecule is made of two hydrogen atoms and an oxygen atom linked together. When these atoms link together in that way, an odorless, colorless, tasteless liquid we call water is formed. When electricity is used to break the water molecules down, hydrogen and oxygen are formed. Hydrogen is an explosive gas with an acrid smell, while oxygen is the gas that we breathe to stay alive. Think about that. Oxygen and hydrogen are each gasses with particular properties. When they link together, however, these individual properties are lost and a new substance is formed. If the links between these atoms are broken, then the atoms separate and go back to their original forms!

In the water portion of the experiment, you saw a molecule (water) breaking back down into its constituent atoms (hydrogen and oxygen). Well, when you pulled the wires out of the water in ten minutes, you saw that the wire connected to the positive terminal of the battery had turned a blueish-green color. In this case, the copper atoms in the wire interacted with water molecules and baking soda molecules, aided by the energy contained in the electricity. The result is a blue-green substance called copper hydroxycarbonate (hi drok' see car' buh nate). Copper hydroxycarbonate is formed when a copper atom links together oxygen atoms, carbon atoms, and hydrogen atoms. In this experiment, the hydrogen and oxygen atoms came from both the water and the baking soda, the carbon atoms came from the baking soda alone, and the copper atoms came from the wire. In this case, then, you observed atoms (copper) linking up with other atoms (oxygen, carbon, and hydrogen) to make a molecule (copper hydroxycarbonate).

Interestingly enough, copper hydroxycarbonate is the same substance that you see on many statues, such as the Statue of Liberty. You see, if a statue has copper on it and is exposed to weather, a process similar to the one that you observed turns the copper atoms in the statue into copper hydroxycarbonate. As a result, the statue turns green, just like one of the copper wires did in your experiment.

The Statue of Liberty has turned green over the years because hydrogen, oxygen, and carbon atoms from various substances in the air have combined with the copper atoms in the statue to make copper hydroxycarbonate.

This is how we get all of the incredible substances that you see around you. Some substances (copper, aluminum, and some others) are simply billions of billions of billions of atoms that form the substance. Other substances that we see (water, salt, sugar, and many others) are made up of billions of billions of billions of molecules. Finally, many substances that we see (wood, cereal, plastics, and many others) are actually mixtures of several different substances, each of which is made up of either atoms or molecules. To reinforce this description of atoms and molecules, study Figure 1.2.

Okay, now we are finally 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 laboratory 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.

Now that I am done presenting the concept of atoms and molecules, you need to answer the following "on your own" problems in order to make sure that you understand what you have read. These kinds of problems will show up periodically, and you should answer them as soon as you come to them in your reading.

ON YOUR OWN


1.1 A molecule is broken down into its constituent atoms. Do these atoms have the same properties that the molecule had?

1.2 When salt is dissolved in water, it actually breaks down into two different substances. Is salt composed of atoms or molecules?


Before you go on to the next section, I want to dispel a myth that you might have heard. In many simplified science courses, students are told that scientists have actually seen atoms. They are told that using an instrument called a "scanning tunneling electron microscope," scientists have actually seen atoms. Indeed, students are shown figures such as the one below and are told that the conical shapes you see in the picture are atoms.