Abstract This experiment investigates the rate of photosynthesis by the determination of the time taken for the leaf segment to rise from the bottom of a beaker to the surface. The experiment tested the hypothesis that the rate of oxygen produced can be used to determine the rate of photosynthesis. The results showed that the rate of release of oxygen determined the rate of rising of the leaf segment subject to utilization of carbon dioxide proving that the evolution of oxygen could be used to measure the rate of photosynthesis. Outline of the experiment Photosynthesis is a process that involves two stages namely the light stage and the dark stage. Intermediate products of the light stage are utilized in the dark stage. The light stage involves the enzymatic breakdown of a water molecule into oxygen radicals and hydrogen radicals. Oxygen gas released is used for respiration of got rid off through the stomata based on turgidity of the guard cells. Hydrogen radicals enter the dark stage where enzymatically controlled reaction results in a combination of hydrogen radicals with carbon dioxide to form building units of sugars (acetyl derivatives). The remainder of the report is organized as follows. Chapter one provides information on photosynthesis and the stages through which different phases of photosynthesis undergo to form α or ß-glucose. Chapter two addresses a literature review on photosynthesis based on a determination of the rate of photosynthesis as a function of oxygen gas evolved. Chapter three provides the methodology of the study and the materials that were used. Chapter four discusses the results that were obtained. Chapter five addresses the conclusion and provides information on whether the objective of the study has been achieved or not. Introduction Reiss, Roberts and Monger (2000, p.573) argue that autotrophs are primary producers of food and include plants, algae and photosynthetic bacteria. Plants and algae are phototrophs because they depend on light to biosynthesize food from inorganic molecules. As primary food producers, plants and algae have different pigments that can absorb light energy. Gregory (1971, p.97) indicates that photosynthetic bacteria are chemotrophs because their photosynthetic process is independent of light. Photosynthesis is a process through which autotrophs as primary producers in a food chain or food web biosynthesis food (carbohydrates) from inorganic sources of materials namely water and carbon dioxide. Photosynthesis takes place in leaves in spherical cell organelles known as chloroplasts that contain pigments that can absorb light. Reiss, Roberts and Monger (2000, 574) indicate that chloroplasts are located in the palisade cells of the leaf. Light is an important element for photosynthesis because it is required during the first stage of photosynthesis known as photolysis. Photolysis is a process that involves the breakdown of water molecules into oxygen gas and hydrogen radicals and the process is exothermic because it involves the release of chemical energy. Photosynthesis occurs in two stages namely the light stage (photolysis or light-dependent stage) and the dark stage (light-independent stage). Summary of the