Ocean acidification, the lowering of seawater pH due to increased concentrations of carbon dioxide in the atmosphere, is an emerging environmental challenge associated with climate change. This publication is intended for Florida grade eight educators and other environmental educators of middle school students. We designed a lesson plan to reinforce fundamental concepts in acid-base chemistry, including the pH scale, and to introduce students to waterbody acidification, its negative effects on shell-forming organisms, and the potential role of aquatic plant metabolism (i.e., photosynthesis and respiration) in mitigating these effects. The goal of the lesson plan is to encourage students to link water chemistry and biological processes while learning about the challenges and potential solutions to acidification within a local context. This lesson plan will contribute to state learning standards while generating appreciation for the complexity of the natural environment.