May be extended into longer-term research projects or personalized instruction. Structure and direction are necessary if the materials are potentially dangerous or the desired conditions and observations quite complicated. More likely to be contained within a single period. Structured labs may be appropriate early in a course, when introducing new instruments or experimental techniques, or when the required experimental conditions are elusive and unusual. For an example, see the Lunar Phases lab.
Concrete experiences become meaningful only when students think about what they are doing.
Student-student interactions make students more aware of their own reasoning strategies. Formal thinkers will model reasoning skills for others. Sometimes students who have just discovered something are the best teachers. Concrete thinkers will ask penetrating questions of those whose grasp of the matter is formal, challenging them to rethink, extend, or better articulate their ideas. We rarely understand something clearly until we have to explain it to someone else.