silverwollfie Posted December 1, 2011 Report Share Posted December 1, 2011 (edited) I'm doing a photosynthesis lab in which I'm taking 5 different lamps, putting 5 different colors of cellophane (red, blue, yellow, green, purple) over the bulb to change the wavelength of the light. A beaker full of water will be placed below after placing a plant in the water so it's fully submerged. Then I'll use probes to measure the pH every 10 minutes. This is a 5x5 experiment so I'll have five plants per lamp. What I'm wondering is what type of bulb should I use in the lamp and also what type of plant I should use. Really I would think any plant would work and I think UV bulbs would work just fine (though using plain white ones if possible would be more cost effective). It'd be awesome if I could get some advice on this Edited December 2, 2011 by Mahuta ♥ Reply Link to post Share on other sites More sharing options...
MattChu Posted December 2, 2011 Report Share Posted December 2, 2011 Just recently did a lab similar to this in HL. Always have a control group so maybe without any cellophane and just pure lamp light? Any lightbulb worked for our experiment so I'm pretty sure it is fine. As long as the wavelength is changed so that only the wavelength you want is hitting the plant. Make sure the cellophane doesn't burn when it's so close to the light bulb. For our lab, instead of covering the lamp, we covered each beaker. That way any other light source (if you are doing it in an area with another light) will still give the wavelength we want for the plant. Reply Link to post Share on other sites More sharing options...
Sandwich Posted December 2, 2011 Report Share Posted December 2, 2011 Underwater experiment? Underwater plant. Pond weed would do. We did a similar experiment using pond weed for GCSE (pre-IB) only counting bubbles of CO2 rather than using a pH probe as the measure, and using a normal bulb in a normal lamp. The important bit is just keeping the distance between plant and lamp constant.I'm not 100% about using 5 plants per lamp, it seems very unnecessary. Why not just repeat with the same plant 5 times? Other plants will have potentially different numbers of leaves, sprouts etc. which obviously changes the surface area and potentially rate of photosynthesis of the plant. It seems to me that a superior control would be to repeat with the same plant? Reply Link to post Share on other sites More sharing options...
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