The same worksheet was given to both treatment groups. It was comprised of both drill- and- practice items and critical- thinking items. The full range of cognitive operations were called into play in that single worksheet. It began with factual questions asking for the units of electrical quantities. Next, the questions involved simple applications of Ohm's law and Watt's law or power formula. The factual questions and the simple application questions were analogous to the drill- and- practice items on the posttest. The questions that followed required analysis of the information, synthesis of concepts, and evaluation of the solution. These questions were analogous to the critical- thinking items on the posttest. When designing the critical- thinking items it was ensured that they would require extensive thinking. Both sections had the same treatment time.