Group 1 Light Colours and Photosynthesis Which colour of light is the one that creates an optimum level of photosynthesis? Group Members: Jimena Vasquez Ana Cristina Ferreiro Nicolás Vidrí Rigoberto Soto

BACKGROUND INFORMATION Carbon Dioxide + Water ( +light) Glucose + Oxygen Pond Weed Is entirely green = chlorophyll Chlorophyll Traps light to use this energy to photosynthesize

Violet Light The visible violet light has a wavelength of about 400 nm Violet Light The visible violet light has a wavelength of about 400 nm. Within the visible wavelength spectrum, violet and blue wavelengths are scattered more efficiently than other wavelengths. Blue Light The visible blue light has a wavelength of about 475 nm. Because the blue wavelengths are shorter in the visible spectrum, they are scattered more efficiently by the molecules in the atmosphere.

Green Light Yellow Light The visible green light has a wavelength of about 510 nm. Pond Weed, appears green because all of the colors in the visible part of the spectrum are absorbed into the leaves of the weed except green. Green is reflected, therefore pond weed appears green. Yellow Light The visible yellow light has a wavelength of about 570 nm.

Orange Light The visible orange light has a wavelength of about 590 nm. Red Light The visible red light has a wavelength of about 650 nm.

AIM To find out what colour produces the highest or optimum level of photosynthesis in pond weed. Colours: Red Orange Yellow Green Blue Violet

HYPOTHESIS Green will produce the least oxygen. Violet will produce the most oxygen. Chlorophyll causes green to be reflected, violet will be more properly absorbed.

WHY? This will change because chlorophyll, which is green, traps light in order to photosynthesize, so some colours will be reflected more than others.

VARIABLES Independent the color of the light Dependent Amount of oxygen produced by plant  Controlled Weed from the same pond, same type, same area Light intensity Amount of time light shines: 10 minutes Mass of pond weed: 35 grams.

METHOD Prepare a box. Hole on top for the bong Light bulb inside One end which can be easily opened and closed Prepare separate frames/screens of see-through color paper. yellow, orange, blue, purple, green and red.

Prepare 6 different litter bottles 10 ml with sodium hydrogen carbonate solution 35 grams of same pond weed (cut both ends of the pond weed so the reaction is faster)

Setup the box. Bulb at the back and ready to be plugged in First screen of colored paper placed in front of the bulb bottle with the pond weed at the other end top of bottle coming out of the box in the hole The bottle should be closed with a bong with connects it to a gas syringe which is being hold up by a clamp stand.

DIAGRAM Diagram showing our set up inside the box, using the blue filter.

VIDEO Close the box in a way that no light goes in or out. Turn on the light bulb, start the stopwatch and wait for 10 minutes, record the amount of oxygen produced by reading off the syringe. Repeat steps 4, 5 and 6 with the other five colors. VIDEO

Amount of oxygen produced (ml) RESULTS Color of light Wavelength (nm) Amount of oxygen produced (ml) Red 650 15 Orange 590 19 Yellow 570 5 Green 510 3 Blue 475 9 Violet 400 10

CONCLUSION The red filter lets less light pass through compared to the orange filter, therefore our result for photosynthesis in red light is not as effective as in orange light. The same applies to the purple and blue filters. Purple should have the highest result, but because the paper only allowed little light to pass through, the result was that the rate was lower. Theoretically, purple should be the most effective because it has the largest wavelength. They both let very little light through, and even though they are effective; they are not as effective as they should be. This explain the anomalies in our results compared to the predicted results.

EVALUATION Lack of reliability (few trials). Constant pondweed. It should be run at least thrice per screen and averaged out. Different light sources: Natural or different types of bulbs. Different intensities Use different plants and test their level of photosynthesis.