This process can be described in a very simplified way as Light + water + carbon dioxide sugar + oxygen Through a non-balanced equation using chemical symbols Light + H2O + CO2 Sugar + O2 Or even the balanced chemical equation 6 CO2 + 6 H2O + photons C6H12O6 + 6 O2 → In any case it is important in this point to be aware about a common misconception students’ develop: the oxygen produced in the photosynthesis comes directly from the CO2 molecule. That is, during the photosynthesis the CO2 molecule is divided into two different parts: the carbon atoms go somewhere and the oxygen molecules are excretedinto the atmosphere. This misconception is normally reinforced by simplified formulas like + water + CO2 Sugar + O2”. It may be interesting therefore to askyour “Light students about this in order to determine if this misconception is emerging. This will enable you to react accordingly. The experiment renders photosynthesis visible, enabling students to be introduced to the process and provide the motivation to study photosynthesis and the fact that it is affected by external conditions (concentration of CO2, in this case). This will be the bridge to the next activity, where other factors will be explored. Some pedagogical guidelines Allow students enough time to carry out the experiment in the three different versions, to observe phenomena, to formulate a hypothesis, to try to explain them, and to discuss and debate. In order to promotediscussion and debate, you could organise a plenary where students explain and defend their findings. Another possible strategy is to let students organise their findings asa poster” and havea “scientific poster session (such as would be found at a scientific conference). You might also consider asking students to prepare a brief PowerPoint presentation to communicate and debatetheir findings. Some guiding questions you use (included in the students’ worksheet): What do you think the bubbles are? What is the gas that is collected in the test tube? Give reasons for your answers. Is the number of bubbles significantly different for the three experiments? Do you think that quality” affects the rate of photosynthesis for aquatic plants? “water Do you think these observations should be carried out with a land plant? Give reasons.
This process can be described in a very simplified way as Light + water + carbon dioxide sugar + oxygen Through a non-balanced equation using chemical symbols Light + H2O + CO2 Sugar + O2 Or even the balanced chemical equation 6 CO2 + 6 H2O + photons → C6H12O6 + 6 O2 In any case it is important in this point to be aware about a common misconception students’ develop: the oxygen produced in the photosynthesis comes directly from the CO2 molecule. That is, during the photosynthesis the CO2 molecule is divided into two different parts: the carbon atoms go somewhere and the oxygen molecules are excretedinto the atmosphere. This misconception is normally reinforced by simplified formulas like “Light + water + CO2 Sugar + O2”. It may be interesting therefore to askyour students about this in order to determine if this misconception is emerging. This will enable you to react accordingly. The experiment renders photosynthesis visible, enabling students to be introduced to the process and provide the motivation to study photosynthesis and the fact that it is affected by external conditions (concentration of CO2, in this case). This will be the bridge to the next activity, where other factors will be explored. Some pedagogical guidelines Allow students enough time to carry out the experiment in the three different versions, to observe phenomena, to formulate a hypothesis, to try to explain them, and to discuss and debate. In order to promotediscussion and debate, you could organise a plenary where students explain and defend their findings. Another possible strategy is to let students organise their findings asa “scientific poster” and havea poster session (such as would be found at a scientific conference). You might also consider asking students to prepare a brief PowerPoint presentation to communicate and debatetheir findings. Some guiding questions you use (included in the students’ worksheet): What do you think the bubbles are? What is the gas that is collected in the test tube? Give reasons for your answers. Is the number of bubbles significantly different for the three experiments? Do you think that “water quality” affects the rate of photosynthesis for aquatic plants? Do you think these observations should be carried out with a land plant? Give reasons.
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