Explaining systems: Investigating middle school students' understanding ofemergent phenomena

Science, as with all cognitive activities, is fundamentally a matter of int erpretation sense-making, and explanation. This study focused on a small gr oup of middle school students as they developed understanding of a particul ar type of phenomena: emergent systems. Such systems are notable in that ma cro-level properties emerge as the result of micro-level interactions betwe en system components. I describe students' initial understanding of emergen t systems, as well as the ways in which their thinking came to reflect the following heuristics: (a) recognition that there may not be a singular caus al force underlying the system; (b) distinguishing between micro- and macro -levels of analysis; and (c) comprehending that even small changes at the m icro-level can have significant effects at the macro-level (Resnick, 1994). I conclude by considering some implications for science education. (C) 200 0 John Wiley & Sons, Inc.