1.1 Scientific Investigation
How does scientific learning differ from most other forms of learning?
There are many different subjects that you will study as part of your well rounded education. Knowledge of Mathematics, History, English, and many other important subject areas is important for understanding the world you live in. The study of science is somewhat different than other subjects in that new knowledge in science is often the result of experimentation . The ability to carry out experiments to answer questions is the cornerstone of scientific learning. In carrying out experiments, scientists use a set of guidelines called the scientific method . The Scientific Method There are basic methods of gaining knowledge that are common to all of science. At the heart of science is the scientific investigation, which is done by following the scientific method . A scientific investigation is a plan for asking questions and testing possible answers. It generally follows the steps listed in Figure below . Steps of a Scientific Investigation. A scientific investigation typically has these steps. Scientists often develop their own steps they follow in a scientific investigation. Shown here is a simplification of how a scientific investigation is done. Making ObservationsA scientific investigation typically begins with observations. You make observations all the time. Observations are anything that can be detected with your senses. It may be something you see; smell; taste; hear; or feel. Let’s say you take a walk in the woods and observe a moth, like the one in Figurebelow , resting on a tree trunk. You notice that the moth has spots on its wings that look like eyes. You think the eye spots make the moth look like the face of an owl. Blur your vision slightly. Do you see an owl? Asking a Question Observations often lead to questions. For example, you might ask yourself why the moth has eye spots that make it look like an owl’s face. What reason might there be for this? How did this happen? Is it just coincidence? Do the eyes resemble the pattern on the moth wings? [Figure1] Forming a HypothesisThe next step in a scientific investigation is forming a hypothesis. Ahypothesis is a possible answer to a scientific question, but it isn’t just any answer. A hypothesis must be logical and it must be based on scientific knowledge. A hypothesis also must be falsifiable . In other words, it must be possible to make observations that would disprove the hypothesis if it really is false. For example, assume you know that some birds eat moths and that owls prey on other birds. From this knowledge, you can reasonably assume that eye spots on the wings of the moths might scare away birds that might eat the moth. This is a logical hypothesis. Owls hunt a wide variety of small prey animals, including birds. [Figure2] Testing the HypothesisTo test a hypothesis, you first need to make a prediction based on the hypothesis. A prediction is a statement that tells what will happen under certain conditions. It can be expressed in the form of an "if - then" statement: If A occurs, then B will happen. Based on your hypothesis, you might make this prediction: If a moth has eye spots on its wings, then birds will avoid eating it. Next, you must gather evidence to test your prediction. Evidence is any type of data that may either agree or disagree with a prediction, so it may either support or disprove a hypothesis. Evidence is usually gathered by anexperiment or by making observations . Assume that you gather evidence by making more observations of moths with eye spots. Perhaps you observe thatbirds really are less likely to prey upon moths with eye spots. This evidence agrees with your prediction. Wrens with a small moth. [Figure3] Drawing ConclusionsEvidence that agrees with your prediction supports your hypothesis. Does such evidence prove that your hypothesis is true? No; a hypothesis cannot be proven conclusively to be true. This is because you can never examine all of the possible evidence, and someday evidence might be found that disproves the hypothesis. Nonetheless, the more evidence that supports a hypothesis, the more likely the hypothesis is to be true . If you were a bird approaching this moth, what might you think? [Figure4] Communicating ResultsThe last step in a scientific investigation is communicating what you have learned with others. This is a very important step because it allows others to test your hypothesis. If other researchers get the same results as yours, they add support to the hypothesis. However, if they get different results, they may disprove the hypothesis. When scientists share their results, they should describe their methods and point out any possible problems with the investigation. For example, while you were observing moths, perhaps your presence scared birds away. This introduces an error into your investigation. You got the results you predicted (the birds avoided the moths while you were observing them), but not for the reason you hypothesized. Other researchers might be able to think of ways to avoid this error in future studies. |