This study explored the effects of Problem-Based Leaning (PBL) with web-anchored instruction in nanotechnology on the science conceptual understanding, the attitude towards science, and the perception of science in society of elementary students. A mixed-methods approach was used. Subjects (N=46) participated in the study for approximately two and a half weeks. A pretest was administered for science conceptual understanding and for attitude towards science. An intervention, web-based nanotechnology anchor, "Catching the Rays," followed. "Catching the Rays" navigated subjects through a nano quest on sunscreen. After the intervention, a posttest was administered for each science conceptual understanding and attitude towards science. Following, a purposeful selection of interviewees (N=6) participated in a Nano Post-Interview. Pretest/posttest data were analyzed using a paired t test. Results of the paired t test for science conceptual understanding (post- being larger than pre-, p less than 0.01) and attitude towards science (post- being larger than pre-, p less than 0.01) were significant at the p less than 0.05 alpha level. Nano Post-Interview data were coded and analyzed independently by two raters for emerging themes. Two themes of "Risks and Benefits" and "Solves Problems" emerged from subjects' (N=6) responses to perception of science in society questions. The theme of "Risks and Benefits" strongly suggests that subjects have a positive perception that nanotechnology comes with risks and benefits to society. The theme of "Solves Problems" strongly suggests subjects have a positive perception that nanotechnology is governed by society's needs and is used to help solve society's problems. Findings from this study suggest that PBL with web-anchored instruction in nanotechnology had a positive effect on subjects' science conceptual understanding, attitude towards science, and perception of science in society. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]