August 15, 2016 by HCDE-Texas
It’s back-to-school time, and teachers are busy attending professional development. In addition to learning new teaching and learning strategies, science teachers should also be thinking about how to ensure that their students have a good understanding of how science actually works. The first week of school is a great time for making sure your students understand the nature of science, or how science works.
Do not teach your students that there is a “scientific method.” I know you may have posters for this, and it may even be in your textbook or other curriculum materials. However, telling them that science always follows these steps leads to deep misconceptions about how science actually works.
The scientific method includes steps to experimental design, which is not a method used by all scientists. By teaching that there is only one correct step-by-step way to do science, students may have a difficult time understanding that there are many more paths to scientific understanding. In some cases, laboratory experimentation is not possible. For example, a population biologist may carry out ecological sampling techniques to study long-term changes in animal and plant populations. This is not a controlled experiment where one variable is manipulated, but it is definitely science.
Many discoveries in science had nothing to do with the scientific method. When Alexander Fleming accidentally left the cover off a petri dish in his lab, the bacteria he was cultivating was contaminated with mold spores. Then he noticed that the bacteria stopped growing. He did not start with a hypothesis; he started with an observation. It was probably something like: “Hmmm. That’s weird.”
Many fields of science are based on other types of scientific knowledge such as building models or examining evidence. For example, atmospheric scientists create computer programs to model and predict hurricane movement. A geologist might look at core samples or landforms to try to determine what happened in the past. These studies collect evidence, but they do not rely on controlled experimentation. Bioinformaticists (scientists who studies genomes) can generate enormous amounts of data about gene sequences. Their study doesn’t always start with a hypothesis; it might start with a question, such as whether temperature can turn a gene on or off.
In Texas, our science curriculum standards (Texas Essential Knowledge and Skills) do not require students to independently do experimental investigations until fifth grade. In K-4, students are asked to perform descriptive investigations. A descriptive investigation will not have a hypothesis. (It may have a prediction instead.) The descriptive investigation will not have variables, and it might not even have collected data to analyze and interpret. Students can become very confused when teachers tell them that science follows a “scientific method,” and then they never follow that method in science investigations.
So what should we tell students about how science works? Instead of teaching “scientific method” we should teach about the practices of science. This is part of the Science TEKS as well. It is also part of the conceptual framework outlined by the National Research Council in A Framework for K-12 Science Education: Practices, Crosscutting Concepts and Core Ideas (online at www.nap.edu/read/13165/chapter/4).
When learning science, students should know and be able to do the following:
1. Ask questions and define problems
2. Develop and use a model
3. Plan and carry out an investigation
4. Organize, analyze and interpret data
5. Use mathematical and computational thinking
6. Construct explanations and design solutions
7. Obtain, evaluate and communicate information
8. Engage in argument from evidence
Note the lack of a firm step-by-step process. The term hypothesis is not even mentioned.
So how should students really learn how science works? Students learn by actually doing science. After completing a descriptive investigation, let students use a metacognitive approach and analyze their steps in the process. They may find that the steps were not exactly linear or that they have more questions than they did when they started. Let them compare their actual steps to the steps in a “scientific method” poster. Students can then understand that although they carried out a scientific investigation, they did not follow a prescribed “scientific method.”