The third step in the ADI instructional model is called the
production of a tentative argument. This component of theinstructional model calls for students to construct an argument
that consists of a claim, evidence, and a rationale on a medium
(such as a large whiteboard) that can be shared with others. In
our research, we define claims as a conclusion, conjecture,
explanation, descriptive statement, or an answer to the research
question. The evidence component of an argument refers to
measurements or observations gathered by the students that are
used to support the validity or the acceptability of their claim.
This evidence can take a number of forms ranging from traditional numerical data (e.g., pH, mass, temperature) to observations (e.g., color, descriptions of an event or product). However,
in order for this information to be considered evidence, it needs
to either be used to show: (i) a trend over time; (ii) a difference
between groups or objects; or (iii) a relationship between
variables. The rationale component of an argument consists of
one or more statements that explain why the evidence supports
the claim and why the evidence provided should count as
evidence. Figure 2 provides a diagram that illustrates how we
conceptualize the various components of a scientific argument