How can the instrument introduce its own explanation?
A real conductivity comparison needs a suitable standard, a clean probe and a recorded temperature. A residue comparison needs a clean vessel and a blank carried through the procedure. These controls test whether the apparatus adds the apparent signal.
Sources for this view
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EXPLORE THE MODEL
Choose complementary observations
Which evidence will you request?
Every case is one of these three possibilities: distilled water, sodium chloride solution or glucose solution at 25 °C. Begin without assuming its identity.
Observations obtained
No observations yet.
3 compatible candidates
- Glucose solution
- Distilled water
- Sodium chloride solution
The supplied evidence still permits more than one explanation.
Choose an observation below. Keep all explanations compatible with the observations obtained so far. More than one candidate is a valid result when the evidence is insufficient.
What this model can establish
Three authored 100 mL cases at 25 °C: distilled water, 0.010 mol/L NaCl, 0.010 mol/L glucose. Qualitative responses are supplied, not measured. Conclusions apply only to these candidates; no drinking-water safety inference.
Optional: check your understanding
MAKE THE CONNECTION
The blank vessel leaves residue after the same handling. What should change?
Sources for this view
HISTORY THROUGH EVIDENCE
Why ions changed the explanation
Electrical behavior of solutions became evidence about particles that could not be seen directly.
Explore how the evidence changed the explanation →