The purpose of this study was to examine whether there is a difference in high school students' achievement and retention on standardized tests between students who participate in inquiry-based laboratory activities and those that participate in traditional style laboratory activities. Additionally, student and teacher opinions of inquiry-based activities will be examined. The research questions addressed by this study included the following: 1) will inquiry lab activities increase subject matter content knowledge and retention of material for the students involved; 2) will there be a difference in higher level thinking skills and subject matter knowledge between students participating in the inquiry labs activities and the students participating in the traditional lab activities; 3) what are students' opinions of the activities as compared to previous hands on learning experiences; 4) what are teachers' opinions of the inquiry activities versus the traditional activities; and 5) how will the results of this research compare with the known inquiry-based learning research? The 166 participants were ninth and tenth graders distributed among eight science classes studying biology. Four classes were taught using inquiry methods (treatment group, two per teacher) and four classes were taught using traditional methods (control group, two per teacher). The results of the current study indicate that there is a difference in higher level thinking skills and subject matter knowledge between students that participate in inquiry laboratory activities and the students participating in traditional lab activities. The treatment group averaged 5.6 points higher on their lab notebook grades than the control group. The inquiry lab activities did increase subject matter content knowledge and retention of material for the students involved. For Teacher 1, the treatment group's improvement was 18.71 points. For Teacher 2, the treatment group's improvement was 31.49 points. The combined treatment group's improvement was 25.42 points. This was 4 to 7 points higher than the control groups' improvement. The students enjoyed the inquiry activities. They found them to be fun, challenging and helpful for learning the material. The teachers enjoyed teaching the inquiry labs and stated that they will continue to use these activities along with other inquiry labs in the future. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]