Investigating Light in Photosynthesis Experiment PDF
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This is a document detailing an experiment on the role of light in the process of photosynthesis. The experiment involves preparing a control and experimental set-up to observe the presence of starch in leaves exposed and not exposed to light. The variables such as presence of light and presence of starch are investigated with controlled factors like supply of carbon dioxide, oxygen, and water.
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Investigating whether light is necessary for photosynthesis To find out whether light is necessary for photosynthesis Apparatus and materials per group boiling tube 1 insulating mat 2 gas...
Investigating whether light is necessary for photosynthesis To find out whether light is necessary for photosynthesis Apparatus and materials per group boiling tube 1 insulating mat 2 gas lighter 1 beaker (250 cm’) 1 tripod 1 potted plant with green forceps 1 pair wire gauze 1 leaves 1 glass rod 1 scissors 1 pair aluminium foil white tile 1 paper clip 1 iodine solution Bunsen burner 1 table lamp 1 alcohol (70%) Carrying out the experiment 1 Your teacher will give you a destarched plant. Pick a leaf from the plant. 2 Carry out iodine test to test for starch in the leaf (see Practical 7.3). Caution * Wear disposable gloves. « lodine is harmful. Avoid contact with skin. - « Alcohol is flammable. Use the smallest volume as far as possible. ® Ensure the room is well-ventilated. Use it only in the absence of naked flame. 3 Use a piece of aluminium foil to wrap part of a leaf on the plant. The wrapped part is not exposed to light. It is the control set-up”. Draw a labelled < A control set-up is used to ensure diagram of the leaf in the space on the next page that any change observed in the experimental set-up is due to the factor to show which parts of the leaf are exposed to under investigation but not other light and which part is not. factors. 4 Leave the plant in bright light for four hours. aluminium foil 5 Pick the leaf wrapped with aluminium foil from the plant. Remove the aluminium foil from the leaf. 6 Carry out iodine test to test for starch in the leaf Designing control set-ups We often include a control set-up in an experiment. The control set-up -- Experimental set-up is identical to the experimental set-up except that the factor under investigation is absent. It is important not exposed to light for ensuring that any change observed (the factor under investigation is absent) in the experimental set-up is due to the factor under investigation but not other factors. Setting a question Is light necessary for photosynthesis? Identifying variables Independent variable | Presence of light Dependent variable Presence of starch Controlled variables Supply of carbon dioxide Presence of chlorophyll Supply of oxygen Supply of light O Supply of water Temperature
