Teaching science requires a basic understanding of the philosophical principles underlying the scientific method. This article will provide an overview of the ideas you need to know to teach science.
The scientific method is often described using a giant flow chart with all kinds of different possible routes. But in reality, doing science is akin to troubleshooting. It goes like this: come up with a question and make a guess about the answer. In other words, make a hypothesis. Then, design and conduct an experiment to test that hypothesis. Lastly, use what you learned from the experiment to evaluate your hypothesis, making ng changes as necessary. This means science is all about testing our ideas to see if they match reality in order to have a useful understanding of how the world works. Useful in the sense that we can make accurate predictions. It is important to note that science is the process of discovery and not the results of that process. Science makes no claims. Instead, science gives us a process to investigate the claims we make.
Not all information is equally valid or useful. We use the levels of scientific truth to quickly convey our confidence in the truth of a statement. At the bottom are the time ideas we hold with the least confidence, and at the top what we hold with the most confidence. We start with a hypothesis. Hypothesis are just our own untested ideas. We hold no confidence in them. Next is fact. A fact is a singular observed event. Facts require a subjective observer. A single fact can be wrong as the observer could have made a mistake. One fact on its own is held with little confidence. Next is a rule. Rules provide a prediction that will get us a range of results. They won’t always be correct, but they will be close. Rules have been tested against many facts. In other words, there is a lot of data to back up a rule. Because we have lots of facts, our confidence increases. Laws can produce accurate predictions within limits. Laws work so long as certain conditions apply. They produce more reliable results than rules. In other words, they line up better with the facts. Lastly, the highest level of scientific truth is theory. Theories are models that can produce accurate predictions in any context. Laws can only be applied in certain circumstances, but theories apply everywhere.
All levels of scientific truth are supported by the levels below it. Hypothesis support facts by helping us look for areas to observe facts. Facts support rules, laws, and theories by providing points of data. Rules support laws and theories by providing a rough pattern to the facts we have collected so we can think about the facts as a group. Laws support theories in a similar way to rules, but with a more defined space. Theories are supported by all of the lower levels.
Theories must, first and foremost, be tools. Theories are a model of the universe that we can use to enrich our lives. The job of a theory is to produce accurate predictions. When we discover new data, that does not align with our theories, we have two options. First, we can modify our theory to adjust for the new data. Second, we can discard the theory in favor of another more accurate theory. If we are going to be scientists, real scientists, we cannot hold on to a theory that has been proven false.
The statement above might seem wildly inaccurate, but it is in fact true. Science does not produce dogmas (despite what Fraces Crick might tell us*). Dogmas are ideas that cannot be challenged but must be accepted and kept, dogmatically (hence the name). Science must leave room for any idea to be disproven. Even our most beloved theories are subject to scrutiny. In fact, they should be subject to the most scrutiny. The ideas science produces are meant to be tools that we use. Theories will likely be used most frequently, so we had better be sure to check them often. Just imagine using a ruler without ever checking to see if the measurements were right! Everything would be off! Sure, it would look internally consistent, but once you put it to the test, it fails. So we check and double-check, and triple check, and then we ask someone else to check it too. We are never 100% sure that our theories are true. We must always leave room for a better theory to take its place. Theories cannot be proven, for if they were they could not be replaced with something that works better. So do not tie yourself too tightly to any idea. It might seem right, but something better could come along. Leave enough room to change your mind.
*Fraces Crick described the movement of genetic information as the ‘Central Dogma of Molecular Biology’ and it turns out he wasn’t entirely correct. Dogma was too big a word.
Often confused accuracy is how close a measurement is to the true value, while precision is how repeatable the measurement is. Ideally, all data collected is accurate and precise. In other words, we have the right idea and we can repeat the results. However, science is not always so straightforward. Remember the ruler analogy from the last point? Calibrating the instruments we use is essential. I cannot tell you how many times I have seen students take measurements without taring the scale. A simple mistake, but a costly one. If we do not calibrate our measuring devices we get high precision and low accuracy. Likewise, if we are very careful with our measuring devices, but we are measuring all of the wrong things, we have made an equal mistake. Knowing our errors, and possible errors helps us gauge the validity of our data. This is why we need multiple sources of data. The milk looks like it has chunks in it, it smells bad, and the best by date is two months old. All three data points give us the clue that the milk has gone sour. Now that is an exagerated example, but the point remains the same. The more lines of evidence, the stronger our confidence that the data is correct.
The philosophy of science is a way of thinking, a way of investigating the natural world. It has limitations, but those limitations provide definitions for a most beautiful form of inquiry. If you want to encourage your students’ understanding of the philosophy of science try the Free Principals of Science Quiz. It will help you discover your students preconceived ideas about science, which with any luck, will help you have wonderful scientific discussions. Need a lesson to teach the scientific method? Try this self-paced lesson!
