What are some common laboratory experiments to study photosynthesis?

Common experiments to study photosynthesis include the leaf disc experiment, the Elodea experiment, and the starch test.

The leaf disc experiment is a popular method to study photosynthesis. In this experiment, leaf discs are submerged in a solution of sodium bicarbonate and exposed to light. The rate of photosynthesis is measured by observing the rate at which the leaf discs rise to the surface. The sodium bicarbonate provides carbon dioxide, a necessary ingredient for photosynthesis, and the light provides the energy needed for the process. By varying the light intensity or the concentration of sodium bicarbonate, students can investigate how these factors affect the rate of photosynthesis.

The Elodea experiment is another common method. Elodea is a type of aquatic plant that produces oxygen bubbles during photosynthesis. By placing a sprig of Elodea in a test tube of water and exposing it to light, students can observe the production of oxygen bubbles. The rate of bubble production can be used as a measure of the rate of photosynthesis. Again, by varying the light intensity or the concentration of carbon dioxide in the water, students can explore how these factors influence the rate of photosynthesis.

The starch test is a classic experiment to demonstrate that photosynthesis has occurred. In this experiment, a leaf is boiled in alcohol to remove the chlorophyll, then stained with iodine. If photosynthesis has occurred, the iodine will turn blue-black in the presence of starch, a product of photosynthesis. This experiment can be used to show that light and chlorophyll are necessary for photosynthesis. For example, if part of the leaf was covered during the light exposure, that part will not turn blue-black, indicating that no photosynthesis occurred in the absence of light.

These experiments provide hands-on experience with the process of photosynthesis, helping students to understand this vital biological process.