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