Current study aimed to examine the effects of web-based instructional material enriched by concept maps, the academic achievement of 7th graders in "Structure and Properties of Matter" unit. The study utilized a quasi-experimental model with pretest-posttest control group design. A sample of the study was composed of 58 students. "Structure and Properties of Matter" unit was taught to the experimental group with computer assisted teaching method, while the same unit was taught to control group by using traditional teaching methods. "Structure of Matter Achievement Test", "Science and Technology Attitude Scale" and "Computer Attitude Scale" were used as data collection tools. The results showed that web-based teaching method was more effective compared to traditional teaching methods in increasing academic achievement in science and technology classes and there is no statistically significant difference in both group attitudes towards Science and Technology Class or computers.