Beginning in about 6th grade, students are asked in their language arts classes to determine the difference between fact and opinion. They begin to understand that if you say, "I think," or "I feel," then you must have something that is a solid, provable fact—data-- to back up or fortify your thinking in order to give your argument and reasoning some validity. Otherwise whatever you are talking or writing about is just a narrative about your opinion. I am a great admirer of mentalist and phenomenological approaches, but even those must be couched in a tight capsule of rigor rather than wandering off into personal musings.
The language of fact v. opinion that we use when we are forming arguments, or establishing and proving hypotheses, is very much the same language of research design--conducting and reporting empirical findings. This can be witnessed at both the word, or “local” level, as well at the whole text, or “global” level. At the local level some of this vocabulary reflects the rigor of our approach—we inquire, explore, measure, analyze, sample, determine, extract, describe, ascertain, and report, for example. At the global level, we will establish a background for our ideas or scenario (ELA: topic sentence, issues and scope; Sciences: importance of the research issue to its conceptual framework). There will be a question (or several questions) for both the (narrative or) argumentative analyst, just as there is for the scientific researcher. An analysis or experiment will be conducted and supported by empirical, or otherwise vetted data. As a result of the inquiry, conclusions will be drawn and sometimes recommendations will be made.
Understanding the reasoning behind the scientific process itself teaches a valuable means of examining a subject to determine if it is fact or fiction. In our lives, we bear daily witness to special interest groups manipulating our emotions with visuals and other media. Competing political interests create biased or fictitious “news” that is released as research, or as other legitimate reportage. What more valuable skill can we provide our students than to teach them the patterns of thought to be able to rationally think through what is before them in order to sort the truth from the fabricated? Or returning back to 6th grade—what is the difference between fact and opinion?
The essence of science is critical thinking: doubting everything, and putting any tentative "fact" through the filters of rational analysis, accepting that the "facts" that survive this process of selection are still tentative. If they can understand that we know nothing for certain, but that some "facts" are possibly (or in the best cases probably) correct, they will be well equipped to deal with a social context that is often trying to pull the wool over their eyes (through advertising, political propaganda, religious dogma, etc.). Critical thinking can and should be taught at all levels of education, adjusting the intellectual depth, conceptual basis, vocabulary, and teaching methods. For high school and undergraduate classes I think Carl Sagan's "Baloney detection kit" and James Lett's "Field guide for critical thinking" are excellent tools. Supplemented with more complex texts, they can even be used at the graduate level (since even graduate students today are often quite deficient in this area).
As an example of a strategy for small children, as soon as my daughters knew how to write, I taught them to keep logs in notebooks whenever they watched television channels with advertisements, explaining how they thought the advertisers were trying to fool them. This made them actively critical instead of passively receptive to messages trying to brainwash them into consuming (or at least wanting to consume) sugary pseudo-foods and toys that would lead them to mindless consumerism.
For Sagan's "Baloney detection kit", see the following documents:
Logical reasoning, critical thinking, analysis and problem solving, among others. We had a project of science and technology with children 6 to 12 years and those were our observations.
Patience in finding answers and solving problems. Logical thinking and looking more deeply into the process of learning. Analyzing problems to determine the best solution. Being creative and thinking outside the box in order to try new strategies to solve older issues.
These are just a few of the characteristics that science builds in individuals!
First of all students can realize that what they are studying are real. Also, doing science project can increase the step by step task completion skill, team work (if any), understand why and what happen according to science.