An analogous knowledge-lean task is the colorless liquid task originally used by Inhelder
and Piaget (1958). Kuhn and Phelps (1982) presented four different flasks of colorless
fluid to fourth- and fifth-graders. The researcher demonstrated that by adding several
drops of a fifth fluid, one particular combination of fluids changed color. On subsequent
weekly sessions, the children’s task was to determine which fluid or combinations of fluids