Photosynthesis Lab Report

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THE EFFECT OF LIGHT FREQUENCY CHANGE ON THE RATE OF PHOTOSYNTHESIS IN SPINACH LEAF DISKS Introduction Photosynthesis is the process in which light energy is converted into chemical energy. Using the energy of light, carbohydrates such as sugars are synthesised from carbon dioxide and water. The name photosynthesis is derived from the Greek words, photo for ‘light’ and synthesis meaning ‘putting together’. Oxygen is also released, as a waste product. Different wavelengths of light are the major factors for photosynthesis. The process of photosynthesis occurs when green plants use the energy of light to convert carbon dioxide (CO2) and water (H2O) into carbohydrates. Light energy is absorbed by chlorophyll, a photosynthetic pigment of the plant,…show more content…
When the air spaces are filled with solution the overall density of the leaf disk increases and the disk sinks. The solution includes a 0.005% of sodium bicarbonate. Bicarbonate ion serves as the carbon source for photosynthesis. As photosynthesis proceeds oxygen is released into the interior of the leaf, which changes the buoyancy causing the disks to rise. Since cellular respiration is taking place at the same time, consuming oxygen, the rate that the disks rise is an indirect measurement of the rate of photosynthesis. Research Question How do different wavelengths of light affect the rate of photosynthesis in which spinach leaf disks rise? Hypothesis I believe that the rate of photosynthesis of the leaf disks will be white, blue, and red, from highest to lowest in that order because white includes all the wavelengths of light. Even though white includes the green wavelength, which will be reflected by the leaf disks, most of the other wavelengths will be absorbed by the leaf disks, increasing the rate of photosynthesis. Thereafter, red will be the second most absorbed wavelength because Variables i) Independent Variable Different light frequencies (white, blue, red) ii) Dependent…show more content…
Push on the plunger until only a small volume of air and leaf disk remain in the barrel about 10% Fill half of the syringe with the sodium bicarbonate-distilled water solution. Tap the syringe to suspend the leaf disks in the solution. Holding a finger over the syringe‐opening, draw back on the plunger to create a vacuum. Hold this vacuum for about 10 seconds and shake it as much as possible in order to do this once. While holding the vacuum, swirl the leaf disks to suspend them in the solution. Let off the vacuum. The bicarbonate solution will infiltrate the air spaces in the leaf causing the disks to sink. You will probably have to repeat this procedure 2‐3 times in order to get the disks to sink if not done properly, but for this lab, they were plunged only once. If you have difficulty getting your disks to sink after about 3 evacuations, it is usually because there is not enough soap in the solution. Add a few more drops of soap. Pour the disks and solution into a clear plastic cup. Add bicarbonate solution. Use the same depth for each trial. Place under the light source and start the timer Start your stopwatch in order to record the exact time at which each of the 10 leaf disks

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