All the societies are in effort to enhance the quality of science and technology education. Turkey was influenced due to the changes in the world and 2004 Science and Technology curricula has been implemented throughout the country since 2005- 2006 academic year.The academic studies on these improvements are not detailed enough and most of them are not objective. In this book 2002 and 2004 Turkish elementary science currricula are compared at grade level 7. For this purpose, the effect of 2004 curricula on the (1) achievement of the students in knowledge, conceptual understanding and higher order thinking skills clusters, (2) attitude toward science and technology, (3) teachers'' classroom activities were evaluated. The results of this analyses indicated no major difference between two science curriculas. This book will take a leading role about curriculum changes in science for curriculum authers, textbook writers, science teachers and pedagogues.It brings new approaches in the evaluation and measurement of cognitive and affective characteristics of students.