Im doing a coursework, im at GCSE level. This coursework is late:-( and this doesnt really need to be included in it, but I was thinking about it. The investigation is simple: How does light intensity affect the rate of photosynthesis? We used the classic method, of pondweed in a beaker of water, with a lamp shining at it, from varied distances for a minute at each. To make sure no other factors affected the rate, we took soem measures. One was to add a spatula full of sodium hydrogen carbonate, to prevent carbon dioxide being a limiting factor to the rate of photosynthesis. what i wanted to include in my coursework was exactly how and what reacts, releasing the carbon dioxide. Sorry if this is a very low level question, its just that, I havent even finished secondary school yet, almost at college, jus need to sort these GCSE's. Id really appreciate some help. Thanks.