Research into students’ thinking about scientific knowledge and processes reveals some common misconceptions and limited understandings (summarized by AAAS¹³):

• Experimentation: Upper elementary- and middle-school students may not understand experimentation as a method of testing ideas, but rather as a method of trying things out or producing a desired out-come.¹⁴ With adequate instruction, it is possible to have middle school students understand that experimentation is guided by particular ideas and questions and that experiments are tests of ideas…. Students of all ages may overlook the need to hold all but one variable constant, although elementary students already understand the notion of fair comparisons, a precursor to the idea of “controlled experiments”¹⁵…. Students tend to look for or accept evidence that is consistent with their prior beliefs and either distort or fail to generate evidence that is inconsistent with these beliefs. These deficiencies tend to mitigate over time and with experience.¹⁶

• Models: Middle school and high-school students typically think of models as physical copies of reality, not as conceptual representations.¹⁷ They lack the notion that the usefulness of a model can be tested by comparing its implications to actual observations. Students know models can