At each grade level, one classroom served as the control
group and the other served as the instruction group. The
control group received no instruction on the topics covered.
At the time of the study, all of the first-grade classes had
received brief classroom instruction on measurement and
temperature, but no formal instruction on the content
included in the guided experimentation. The first-grade
students in both classes were studying animal habitats. The
third-grade students in both classes were learning about
condensation and evaporation.