Concepts related to photosynthesis are presented to the students in this unit. In the first of six exercises, students repeat Blackman’s experiments to gain first-hand knowledge of the reactions that comprise photosynthesis. Other experiments allow the students to investigate the absorption spectrum and the relationship between wavelengths and plant pigments. The association between photosynthesis and starch production is explored. Each exercise is followed by a series of questions to help students think critically about biological topics. At the end of the unit, there are additional questions to review the most important points of the unit and to relate the unit to the students’ everyday life.