Pressing for explanation
During this unit of instruction, Brian pressed for scientific explanations of sound on two levels. First, he pressed students to explain how sound works. He worked with students to construct a story of energy transfers beginning with the vibration of guitar strings, drum heads, and tuning forks transferring energy in the form of a compressional wave through air particles. Students were encouraged to follow the story of the sound from the vibration of an instrument through the movement of a sound wave through air. Finally, Brian helped students understand how sound works by following the sound to the ears of listeners who detect sounds through the vibration of the ear drum and small bones inside of the ear. He supported students’ partial explanations by helping them weave their own ideas together with science ideas, and he looked for ways in which students were beginning to understand sound as a wave of energy transferring through collisions between air particles.
“What happened” explanation |
How/ partial why something happened explanation |
Causal explanation |
The second level of explanation involved helping students expand upon their models of sound waves by pressing them to explain why sounds have different qualities such as a range of pitches and volumes. Brian also pressed students to explain why some of these sound qualities change over time and space and some do not change at all. Brian emphasized important theoretical underpinnings in his press for explanations with students. Students were pressed to think about sound in terms of collisions between vibrating instruments or tuning forks and air particles. Students were also pressed to think about sound in terms of energy transfers. By emphasizing energy transfer and air particles, Brian pressed students to create explanatory models that can help explain many different sound events and that can add to students’ overall understanding of energy and matter (see continuum above).
