Here's a video discussion of the scientific method (11min): SciShow: The Times and Troubles of the Scientific Method on YouTube
Want to learn about how the scientific method really applies to chemistry, in more interactive way? Check out my new project, Chemiatria!
You know what science is. A method is a way to do something. The scientific method is how scientific knowledge is produced. You have probably learned science before as a set of knowledge that is just given to you, and you have to memorize facts and procedures to follow to get answers. This way of learning that you have probably experienced is completely different from how science professionals think of science and do science. Now it is time to learn science like a scientist. Because scientists create new knowledge, they have to be able to think independently. Even if this seems very hard or unfamiliar, you can learn to make new scientific conclusions yourself.
The basic steps of the scientific method involve collecting observations about what actually happens, thinking about what the observations mean, making guesses about what will be observed in the future, and then making observations to see if the guesses are right. The observations are evidence or data, the results of experiments. The guesses are usually called hypotheses. If the hypotheses fit a lot of data and seem to work well, then they are called theories. In science, a law describes a pattern of consistent results. For instance, you know that when you drop things, they fall. That could be called the law of gravity. If we had a good explanation of why that happens, we would call that a theory of gravity. Gravity is easy to describe (in Newton's law, which describes how things move on Earth and how planets and moons and stars moves in space) but very hard to explain: how can objects that are very far apart feel a force towards each other?
The real test of whether something is science is whether it works reliably. An experiment is good and useful if you can repeat it (if someone different can repeat it) and get the same result. There will be some small differences in the data because measurements are always a little imprecise and there might be some small differences in the way the experiment was done, but the data should be the same within the "error range". Likewise, a law is good if observations always follow it, within the context it describes. And a theory is good if it explains all the available evidence. For theories, it's also important that it be possible to prove the theory wrong, that it makes predictions that can be tested. Otherwise, it might be true but it isn't useful. For example, the theory that God created the world and controls it completely can't be proved wrong, and doesn't make very clear predictions either because it is impossible to know how God works. Thus, this isn't a scientific theory. It might be true or it might not, and science can't provide evidence in either direction. This belief might help you live your life well, but it won't help you build a safe bridge or tell you how to design a better battery. For this type of question you need science.
You should have the scientific method in mind when you learn science. It will help you learn better. In this class, you will need to use your knowledge of laws and theories to make predictions about new things. You probably haven't practiced doing that in a long time. To build this important skill, you should practice asking yourself questions as you learn. For instance, when you learn about a law, ask yourself what experiment was done to make those observations? How do we get those results? For any fact you are given, ask yourself (or ask me!): how do we know?
To learn science, you need to build "mental models" of how things work. A model is a small version of something that shows all its parts and how they are related. For instance, an architect probably builds a small 3D model of a new building, before people start building the building. The architect also has complicated computer models of the building showing how it stays up and that the doors don't bump into each other, etc. These models help the architect predict whether that design will be successful.
You already have mental models for lots of things. For instance, you know that things fall when you drop them, and that electronic devices like refrigerators work when you plug a cord into the wall. When you learn physics, you might have to change these models a little bit. For instance, it might be surprising that the acceleration of gravity is the same for everything, since cloth falls more slowly than stones. Or it might be surprising that electricity needs circuits, since you only plug one cord into the wall. Chemistry describes effects that are harder to see in regular life, so you might not have so many mental models already. As you take this course, try to build models of how chemicals behave, just like you already have models of how people behave. Use what you know to make guesses and then test them, and change the model if you have to. One important thing to remember is that a real life situation might require you to use many different models related to different "class topics" at the same time. Try not to keep all the topics we talk about separate. Think about how they fit together.
One big problem my Korean students have had before is that they make models that are relevant only to school, not to real life. For instance, last year I used the same question format (it was, which direction will this reaction go?) to test an acid/base concept on a quiz, then used the same question format to test periodic properties concepts on the final exam. I realized then that all my students had a model that connected that question format to acid/base (even though it was a very general format that could apply to almost anything), because even though there was no acid and no base on the final exam question, they all used acid/base concepts to answer and got it wrong. So please be careful to make chemical models, not school models, because I can easily trick you if you make school models, and school models won't be useful once you finish school.