Research Design

We have conducted extensive individual clinical interviews with experimental and control students from grades 3 through 5 using a repeated measures design. This approach reveals how student’s understanding unfolds over time and helps identify patterns of reasoning across concepts. The experimental students received the Inquiry Project instruction (see Curriculum section). The control students received regular science instruction.

The experimental students were interviewed at four moments over two and one-half years (236 interviews). The control students were interviewed at three moments (110 interviews).

Interview Design

The two-hour videotaped interviews covered children’s understanding of (1) the properties, divisibility and granularity of clay; (2) the measurement of length, area and volume; (3) the relations among weight, size, heaviness of material, and density; (4) water displacement; (5) properties (weight, material, behavior on a balance scale, displacement, volume) of clay before and after reshaping; (6) similar properties as applied to arrangements of solid cubes; (7) the concept of matter, as well as ideas about atoms and molecules; (8) the granularity (fineness of resolution) of numbers and lengths (9) the effects of change of state (grinding and melting) on material objects; and (10) proportional reasoning about the concentration of mixtures (of sugar and water).