Background: Students' motivation for science declines over the early teenage years, and students often find school science difficult and irrelevant to their everyday lives. This paper asks whether creating opportunities to connect school science to authentic science can have positive effects on student motivation. Purpose: To understand how authentic science experiences can affect students' motivation for science and students' goals, values, beliefs and attitudes towards science. Programme description: The Medicine Hunt brought scientists and students together to find bacteria that produce secondary metabolites with antibiotic effects. Scientists received help with collecting soil samples and teachers and students took an active role in research and worked with solving an authentic problem as a part of their ordinary school science over a course of six months. Sample: About 388 students from 18 lower-secondary school classes participating in the Medicine Hunt. Students were enrolled in grade seven to nine (13-15 years old). At this stage, science is compulsory, and all students follow the same science course. The classes represented different geographical regions of Sweden. Design and methods: Students filled in motivation questionnaires before and after the Medicine Hunt. Paired t-tests were used to evaluate how students' intrinsic motivation, goals, values, beliefs and attitudes towards science changed over the project period. Results: Students' intrinsic motivation for school science and plans for future participation in science remained unchanged during the period they participated in the Medicine Hunt, and students' goals, values and attitudes followed the well-documented pattern of decline. Thus, the authentic experience can arrest the well-described decline for some motivation-related factors. Conclusions: The findings suggest that the authentic experience can arrest some aspects of the decline in motivation for science in the teenage years. The paper discusses the processes around students' motivation in relation to authentic experiences.