Let us recall back the equation:
From the equation, it can be concluded that oxygen is produced as a by product of photosynthesis. Now, how do we know that oxygen is really produced? OK, here's the procedure:
From the equation, it can be concluded that oxygen is produced as a by product of photosynthesis. Now, how do we know that oxygen is really produced? OK, here's the procedure:
- Set up the apparatus as shown in the following figure and make sure that the test tube is completely full of water.
- Place the apparatus in bright sunlight for a few days.
- Carefully remove the test tube from the top of the funnel, allowing the water to run out but not allowing the gas to escape.
- Light a wooden splint and then blow it out so that it is just glowing. Carefully put it into the gas in the test tube. If it relights the glowing splint, then the gas is oxygen.
CONTROLS
When setting up an experiment and a control, which of the two procedures constitutes the CONTROL depends on the way the prediction is worded. For example, if the prediction is that "in the absence of light, the pondweed will not produce oxygen", then the control is the plant in the light. If the prediction is that "the pondweed in the light will produce oxygen", then the control is the plant in darkness.
