Question: Does distance from the light source affect the rate of photosynthesis?
For this experiment, we utilized the lab manual “Basics of Life Science” by Brenda Leady, which had the progressions on the most proficient method to do this experiment.
Here is an example of the procedure of the experiment:
1. In a beaker, prepare a solution of 50 mL of water
2. Add 1 drop of dilute liquid soap to the NAHCO3 solution.
3. Using a hole punch cut out ten uniform leaves for each of the beakers
4. Put 10 leaf disks into the barrel of the syringe. Push the plunger down, careful not to crush the disks but pushing as much air out as possible.
5. Put some of the solution into the syringe.
6. With your finger over the tip of the syringe, pull the plunger back, creating a vacuum. While doing this, swirl the leaf disks into the solution. Release the vacuum. Repeat this procedure 2-3 times in order to get the disks to …show more content…
They did not rise as they were not receiving a carbon source; therefore, photosynthesis did not occur, and oxygen was not released in the leaves to allow them to float. In sodium bicarbonate solution, leaves were exposed to a higher level of carbon dioxide. This higher level corresponds to a faster rate of photosynthesis as carbon dioxide is a reactant in this process. Thus, oxygen(product) was released more quickly in the leaf allowing the buoyancy to change and the leaf to rise. Generally, an increase in light intensity corresponds with an increase in rate of photosynthesis.
If the leaves had been exposed to blue light for more than 20 minutes, some may have risen with this extended time for photosynthesis to occur.
When submerged in sodium bicarbonate solution after about 15 min, two leaves had risen. However, they sunk again by the time 20 min was up. This could be due to the fact that there was an excess of carbon dioxide and not enough oxygen was able to get into plants, hindering their ability to float.
Final connection: as photosynthesis occurs, oxygen is released. The accumulation of it in leaves displaces the water and causes leaves to rise. With more intense light sources and higher levels of carbon dioxide, photosynthetic rates increase.
Some possible errors in the experiment include an inconsistency in the distance and angle of the light. Some solutions include setting a precise position for the light and keeping