Aim
To find out if light is necessary for photosynthesis
Theory
Leaves are specialized organs on the stems of plants. Their most important function is to carry out the process of photosynthesis. All the necessary raw materials for photosynthesis come together in the leaf. Water comes from the plants’ roots and carbon dioxide in the air enters through stomata, pores, in the leaf. The reaction for this process is 6H2O+6CO2 sunlight + chlorophyll C6H12O6+6O2. Chlorophyll, the green pigment in leaves, captures light energy. The products of photosynthesis are oxygen and glucose. In the leaf the excess glucose is changed to starch. If photosynthesis is taking place in the leaf, the leaf will contain starch. To test the presence of starch, iodine solution is used. If starch is present, the leaf will turn blue-black showing that photosynthesis is occurring, else it’ll remain yellowish-brown. The independent variable is light. The dependent variable is the production of starch. Some of the controls in this experiment are water, location and temperature.
Materials and Apparatus
Bunsen Burner, tripod, gauze, green plant, test tube with alcohol, iodine, beaker with water, tweezers, watch glass
Diagram
Method
Before we did the real experiment, we put the plant in light for a couple of days and hart parts of the leaf covered by a black piece of paper.First boil a leaf in a beaker of water to soften it. Let it boil for about a minute. Then turn off the Bunsen Burner because alcohol has a low boiling point making it flammable. Put the leaf into the test tube with alcohol and put the test tube into the beaker with water. Heat the leaf in the alcohol to remove the chlorophyll for about 8-10 minutes. Rinse the leaf in water carefully so the leaf doesn’t break but the alcohol comes off. Put the leaf onto a watch glass. Add a little bit of iodine to the leaf. Observe your leaf and notice which parts turn blue-black and which parts stay brownish.
Observations
There was a yellowish-brown stripe through the middle. That was probably were the black paper was. It was also brownish around the edges. Some parts were very black and some more blue. The brown stripe was hard to pretty hard to see. There was no little shape on the leaf but there might not have been one in the paper. The colors kind of ran through each other and it was hard to see a difference. The leaf was also very weak and wrinkly making it harder to see.
Conclusion
The process of photosynthesis can only take place in the presence of light. This was shown in the experiment because the part of the leaf covered with black paper stayed brown but the parts not covered turned blue-black.
Discussion
The leaf was very wrinkled up by the time we boiled it. That made it very hard to see the difference between the blue-black and the yellowish-brown. The leaf even kind of broke a little.
The plant has to have light to produce food. In this experiment, the parts of the leaf that were covered stayed brownish-yellow while the parts not covered turned blue-black. Photosynthesis only takes place in the green parts of a variegated leaf, not the white parts. That is because chlorophyll is green so only the green parts can have chlorophyll in them. Photosynthesis takes place only at day because the chlorophyll needs to absorb sunlight in order for photosynthesis to take place. There is no sunlight at night. Respiration, the opposite of photosynthesis does take place at day and night. If all the green plants on Earth died, so would we. There are two ways. First there would be no more oxygen so we wouldn’t be able to breathe. Second of all the primary consumers, which depend on plants, would die because there would be no plants. If there are no primary consumers or plants, the secondary consumers would also die because they wouldn’t have food. The tertiary consumers would then also die. The scavengers would die because by now, all the predators will have died so they can’t eat anyone’s leftovers. The decomposers would live for a while on the dead plants but would die after having decomposed everything.
To find out if light is necessary for photosynthesis
Theory
Leaves are specialized organs on the stems of plants. Their most important function is to carry out the process of photosynthesis. All the necessary raw materials for photosynthesis come together in the leaf. Water comes from the plants’ roots and carbon dioxide in the air enters through stomata, pores, in the leaf. The reaction for this process is 6H2O+6CO2 sunlight + chlorophyll C6H12O6+6O2. Chlorophyll, the green pigment in leaves, captures light energy. The products of photosynthesis are oxygen and glucose. In the leaf the excess glucose is changed to starch. If photosynthesis is taking place in the leaf, the leaf will contain starch. To test the presence of starch, iodine solution is used. If starch is present, the leaf will turn blue-black showing that photosynthesis is occurring, else it’ll remain yellowish-brown. The independent variable is light. The dependent variable is the production of starch. Some of the controls in this experiment are water, location and temperature.
Materials and Apparatus
Bunsen Burner, tripod, gauze, green plant, test tube with alcohol, iodine, beaker with water, tweezers, watch glass
Method
Before we did the real experiment, we put the plant in light for a couple of days and hart parts of the leaf covered by a black piece of paper.First boil a leaf in a beaker of water to soften it. Let it boil for about a minute. Then turn off the Bunsen Burner because alcohol has a low boiling point making it flammable. Put the leaf into the test tube with alcohol and put the test tube into the beaker with water. Heat the leaf in the alcohol to remove the chlorophyll for about 8-10 minutes. Rinse the leaf in water carefully so the leaf doesn’t break but the alcohol comes off. Put the leaf onto a watch glass. Add a little bit of iodine to the leaf. Observe your leaf and notice which parts turn blue-black and which parts stay brownish.
Observations
There was a yellowish-brown stripe through the middle. That was probably were the black paper was. It was also brownish around the edges. Some parts were very black and some more blue. The brown stripe was hard to pretty hard to see. There was no little shape on the leaf but there might not have been one in the paper. The colors kind of ran through each other and it was hard to see a difference. The leaf was also very weak and wrinkly making it harder to see.
Conclusion
The process of photosynthesis can only take place in the presence of light. This was shown in the experiment because the part of the leaf covered with black paper stayed brown but the parts not covered turned blue-black.
Discussion
The leaf was very wrinkled up by the time we boiled it. That made it very hard to see the difference between the blue-black and the yellowish-brown. The leaf even kind of broke a little.
The plant has to have light to produce food. In this experiment, the parts of the leaf that were covered stayed brownish-yellow while the parts not covered turned blue-black. Photosynthesis only takes place in the green parts of a variegated leaf, not the white parts. That is because chlorophyll is green so only the green parts can have chlorophyll in them. Photosynthesis takes place only at day because the chlorophyll needs to absorb sunlight in order for photosynthesis to take place. There is no sunlight at night. Respiration, the opposite of photosynthesis does take place at day and night. If all the green plants on Earth died, so would we. There are two ways. First there would be no more oxygen so we wouldn’t be able to breathe. Second of all the primary consumers, which depend on plants, would die because there would be no plants. If there are no primary consumers or plants, the secondary consumers would also die because they wouldn’t have food. The tertiary consumers would then also die. The scavengers would die because by now, all the predators will have died so they can’t eat anyone’s leftovers. The decomposers would live for a while on the dead plants but would die after having decomposed everything.
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