00303nam a2200097   450000100070000000500170000700800360002410000160006024500530007626400760012901244020260807101659.0260101s1992    pe      000 0 eng  d1 aNancy Kober10aWhat we know about Science teaching and Learning 1aWashington D.C.bCouncil for Educational Development and Researchc1992