Why the Nature of Science MUST be Taught Explicitly

Much of the science illiteracy in our country can be traced directly to the many misconceptions about science, its realm, its limits, its benefits and its different processes. And most of those errors can be traced to science textbooks at all levels that have persisted over many decades in perpetuating those misconceptions. Of course, many teachers (and their students) base their understanding of science on what they find in those textbooks.

Unfortunately, many elements of the nature of science were omitted or were too weak in the NGSS Core Idea pages and the NGSS Appendix H, even though many were expressed in the 2012 national Framework.

Research clearly shows that students do not automatically learn the nature and processes of science by doing hands-on science or authentic, inquiry-oriented investigations. NOS must be taught explicitly. "... learning about the nature of science requires more than engaging in activities and conducting investigations. (NGSS Appendix H, p. 2)."

NOS, as presented in the NGSS (in its Appendix H, p. 4) includes a list of eight basic understanding categories (or themes) about NOS. In fact, you should read all of Appendix H. In the 2-page tables of Practices and Crosscutting Concepts), there are 26 Learning Outcomes (LOs) expected for middle school, and 32 LOs expected for high school. Those Learning Outcomes are supposed to be included in the Foundation Boxes of each Core Idea page. However, in a sampling of the Life Science Core Idea pages for middle school and high school, very few of those LOs appear (see table below):


Life Science
Core Idea pages

NOS Themes
Cited (out of 8)

Learning Outcomes

Out of X in NGSS
Append. H (NOS)

Middle School





High School





Nothing explicit about NOS is included in the Assessable Components (white area of each Core Idea page). With so little mention of the NOS elements on the Core Idea pages, teachers (and textbook authors) will be unlikely to even notice most (or all) of them, and therefore are not likely to focus on those elements, especially not explicitly (as all research findings say they should). Why isn’t there at least a Core Idea page dedicated to NOS that is equivalent to the other Core Ideas? NOS should be considered just as important as any other “content” topic, if not more so! The 2012 national Framework indicated as much, and that was the basis for the NGSS!

Clear Distinctions Not Made
In order to send the clear message to teachers and textbook authors, old and inaccurate concepts and word usages should be clearly pointed out as such, and be replaced by more accurate terms. Unfortunately, the NGSS NOS tables (Appendix H) fail to do this. Following is a fair sampling of those oversights. if you recognize the importance of NOS, then you should make every effort to address NOS in your course in ways pointed out below:

1. Science & Engineering Practices (SEP - blue table), 4th category: "Scientific Models, Laws Mechanisms and Theories Explain Natural Phenomena." Because of its importance, "Only" should be inserted: "... Theories Explain Only Natural Phenomena." Either there, or elsewhere in the table, absence of supernatural phenomena must be explicitly emphasized, e.g., "... Only Natural Phenomena, Never Supernatural Phenomena, as such." A similar "Only" should also be inserted in the Crosscutting Concepts (CC - green page), 4th category: "Science Addresses Only Questions About the Natural and Material World." The public's lack of understanding about this is a major cause of much of their conflict with science (e.g., about evolution, vaccinations).

2. SEP, 4th row, Middle School column, there are several weaknesses there:
a. Should be: "Scientific theories are well-supported explanations for observable phenomena. They are not guesses, conjecture or speculation, as it's used outside science. [And omit the fifth item "e" below].
b. Should be: "Scientific theories are based on..."
c. Should be: "Scientific Laws are regularities..."
d. "A hypothesis is used by scientists..." should be: "A hypothesis is used by scientists as a tentative explanation for an observed phenomenon that can be tested. It is not "an educated guess" or a "prediction." Notably, Appendix H makes little mention of "hypothesis," tending to use "model" in its place. Probably a good idea. Nevertheless, the frequent uses in textbooks and by teachers of hypothesis as an educated guess or a prediction in an experiment requires that those inaccurate uses be clearly pointed out to teachers and students (via textbooks).
e. "The term 'theory' as used in science is very different from the common use outside of science." Why not just add this to the first item (a) in this list, and omit item e?

3. SEP, top row, High School column, first item: "Science investigations use diverse methods and do not always use the same set of procedures to obtain data. For example, experiments may work for current events, but not for ancient events, where one can only search for clues that are based on current models (or hypotheses)."

4. Same box, third item, add at the end: ", and their testability."

5. Same page, Middle School column, third box down, replace 2n item with "The uncertainty and durability of science findings varies. There are degrees of uncertainty in scientific explanations."

6. On the Crosscutting Concepts page (CC, green), Middle School column, last category, second item (Learning Outcome), should be: Science limits its explanations to systems that lend themselves to observation and empirical evidence: only natural explanations, never supernatural. [This emphasizes that important point].

7. Same box, fourth item (Learning Outcome) should be added: Science is our most successful and reliable way for understanding the natural world, because it works.

8. Same page, High School column, first box, 3rd item: Add at the end: (including the testing of possible explanations).

9. Same column, third box down, 3rd item: Add at the end: This brings bias to science, which is much reduced by using the rules and values of science.

10. Same column, fourth box down, 1st item: Add at the end: "Questions of judgment, opinion, beliefs, and supernatural events, as such, are off limits to science."

If you want to meet those expectations for NOS, I strongly suggest that you take a look at a new resource you may not have yet heard about: Science Surprises: Exploring the Nature of Science. Using that booklet as a text supplement, along with several of the interactive NOS lessons on the ENSI website, your students will meet ALL of the NGSS NOS expectations! The booklet is available as an e-Book, easily accessible to your students using their tablets, at $0.99 per student. A printed version is also available.

More reasons to introduce NOS in depth
at beginning of your school year:

1. Clarifies why science is important, what science IS - and is NOT - how it really works, and the clear meanings for certain key words used in science. It repairs many of the common misconceptions about science, e.g., the myth of “The Scientific Method.”

2. Points out the different ways science works [processes of science], not one scientific method: “the notion that there is a single scientific method of observation, hypothesis, deduction, and conclusion, a myth perpetuated to this day by many textbooks, is fundamentally wrong.” (New K-12 Science Framework, p 78).]

3. Critical/skeptical thinking skills are introduced and practiced. This is critical before dealing with politically sensitive and often misunderstood issues e.g., climate change and evolution. Much of the anti-evolution sentiment stems from misconceptions about NOS.