Why should a homeschool student study chemistry? First, because it is a neat subject. Everything is made up of chemicals, from the kitchen table, to the dirt in the back yard, to the air we breath. It is fascinating to learn more about the world we live in.
On a less lofty note, and closer to home for our student, lab science is a requirement for graduation from high school in many states and chemistry is the most natural science to take as a lab science.
A third reason is to meet college entrance requirements. As I pointed out in my previous articles, just about every college lists lab science as an entrance requirement. Most people opt for biology, but chemistry will serve also. For colleges that require two sciences, chemistry is the usual second, after biology.
To Lab or Not to Lab?
Chemistry lab is messy and possibly dangerous. "Is it worth all the effort if my state doesn't require lab science? Can't I take chemistry without chemistry lab?"
Yes, you can take chemistry without doing chemistry lab and it will fulfill a state's high-school science graduation requirement, but it will be worthless for just about anything else.
To make the most use of your student's learning time, you need to plan your high-school curriculum based on your college goals. Take college chemistry as an example. Let's say your student wants to be a health professional. Biology is a requirement. Most colleges have "Biology for Everyone" and "Biology for Health Professionals." Our local community college has BIO 111, (Introductory Biology I) and BIO 140 (Principles of Biology I) BIO 111 is described as, "For liberal arts students and majors in physical education, therapy, nursing, and other allied health areas." BIO 140 is, "Quantitatively oriented for pre-medicine, pre-dentistry, pharmacy, biology and other science majors." To take the first course, you have to demonstrate an ability to read. To take the second you need reading proficiency plus CHM 105. CHM 105 (General Chemistry I) requires that you have taken either CHM 101 (Fundamentals of Chemistry) or a year of high-school chemistry. A year of high school lab chemistry (since CHM 101 is a lab course), saves you taking CHM 101 at the community college and lets you take Biology a semester sooner.
To AP or Not to AP?
The difference between high-school chemistry and AP high-school chemistry is that the second prepares your student to take the AP General Chemistry exam offered by The College Board. A good score on the AP chemistry exam earns you college credit in chemistry and allows you to proceed to more advanced courses earlier in your college career.
In the case of the sequence I began to outline above, you could take biology starting in the first semester of your freshman year in college - a semester earlier than if you took lab chemistry but didn't take the AP test, and a whole year earlier than if you had not taken chemistry in high school or if you did not include a lab.
Most high-school chemistry curriculum does not prepare a student fully for the AP exam. In that case a second year of advanced chemistry, also aptly called AP chemistry, is taken in the student's senior year. Apologia Chemistry, for example, is divided this way. The second year is not necessary if the chemistry course is paced to include the extra AP material at the end of the course.
What to Teach in High School Chemistry
From the description in the Apologia catalog, high-school chemistry includes the following topics:
- Significant figures
- Units of measurement
- Classes of matter and different kinds of compounds
- The mole concept
- Acids and bases
- Redox reactions
- Atomic structure
- Lewis structures
- Molecular geometry
- The gas laws
In addition to these topics an AP/Advanced Chemistry course includes:
- Limiting-reagent stoichiometry
- Atomic and molecular orbitals
- Intermolecular forces
- Nuclear chemistry
- Organic chemistry
A number of topics from the first course are repeated in the AP course, presumably in greater depth and detail and with more of the associated mathematics included. These two courses together cover everything in a full year of college chemistry.
Note: AP Chemistry requires the student to have taken Algebra II, so an additional step in your curriculum planning should be to make sure your student covers Algebra I and Algebra II before tackling AP Chemistry.
The college credit you will earn from taking AP Chemistry depends on the score you get on the AP examination and on the particular college's rules. Our community college requires a 3 or better to give credit for a year of chemistry. At University of Missouri-St. Louis, a 3 or better will earn you 5 credits, i.e., one course's worth of credit. At St. Louis University, a 4 or better earns you 8 credits, which in their case is two courses worth of credit. At the United States Military Academy at West Point a 4 or 5 "can be important in validating chemistry." MIT doesn't give any course credit for chemistry as a result of the AP exam. You can however take MIT's chemistry placement exam, given once a year during freshman orientation, and if you know the material well enough, you will be given credit for the first year of chemistry and be allowed to take more advanced courses.
Documentation. Take pictures of every experimental setup you do and of you doing the experiments. Keep a portfolio of the pictures.
Lab safety. It's never too early in your science career to begin to learn lab safety. Yes, I know, the strongest acid most of you will use is likely to be vinegar or lemon juice and the strongest base will be ammonia or baking soda, but if you get into good habits in your high-school chemistry, these will carry over into college and beyond.
Simple rules of lab safety include these:
- Wear long pants, solid toed shoes, and a short-sleeve shirt or at least one that doesn't have sleeves that hang down. It should also cover the midsection completely.
- Always wear goggles
- Wear rubber gloves when handling toxic or corrosive chemicals
- If you need to heat something, use an alcohol burner, a hot plate, or a water bath on the stove. Don't use the microwave! If you use an open flame, keep flammable liquids capped and far away.
- Accidents can happen, so plan what you will do if something breaks or something spills. If you get something in your eyes, you will have to flush them with water, so know where to go and what to do when you get there.
Again, most home experiments don't deal with anything extremely dangerous, and safe practices will prevent accidents. These procedures are just in case.
Lab notebook. Keeping a good lab notebook is what separates playing at lab from really doing lab. Any honest experimentation or research requires that everything be documented in a lab notebook.
The most important thing about your lab notebook is to keep it honest. Write in non-erasable ink. If you make a mistake, cross out and write the correction afterward. If necessary, explain why something is crossed out. Label your computations. If you doodle something in your lab notebook identify it as a doodle and not important. The lab notebook is for other researchers who may want to duplicate your work. Keep them in mind.
You will need a composition book - one of those with the mottled black covers. Notebooks with removable pages are no good for the same reason why writing in pencil or erasable ink is no good. If researchers could erase or remove unfavorable results, that would encourage science fraud.
Number all the pages in the upper outside corner. Let page 1 be the table of contents with columns for experiment number, experiment name and page number.
My organic chemistry teacher had us write our labs only on the right-hand pages, but this is optional. It does leave the left pages open for recording your computations.
|Where to Get It: A Nonexhaustive List
Courses With Labs
A Beka, Alpha Omega Publications, Apologia Educational Ministries, BJU Press, Castle Heights, Christian Light, Quality Science Labs (formerly Microchemkits), University of Nebraska-Lincoln's Independent Study High School
Lab Supplies and Equipment
Each lab writeup should contain:
- Lab number and title
- Purpose of the lab, including what you expect the results to be
- Sketch or picture of the apparatus used, if applicable
- Show a balanced equation for the reaction you will be observing
- List the chemicals used, if any, in a table, with their formulas, atomic weights, melting points, boiling points, how much measured out in grams, and in moles.
- Record your procedure and observations as you are doing them, avoiding the first person, e.g. "Set up this, weighed out this much of this chemical, mixed the chemicals in this way, heated at this temperature for this long. Noticed this change of color, or bubbles, or something melted (or burned)." Record exactly what you did, even the mistakes and mishaps. These may affect the results and might be important to recreating some unintended but desirable result. (Remember the discovery of the vulcanization of rubber.)
- Record your data in a table. This includes all the measurements you made: temperatures, mass of reaction products, how much product did you expect to get, how long the process took, etc.
- Record your conclusions. What happened? If it didn't match your expectations, conjecture why not. What mishaps happened? How might they be prevented in future experiments? Did you get as much product as you should have? Where might you have lost some? What did this experiment tell you about chemistry?