Types of Light and its Affect on Photosynthesis Jimmy Butler, Shea Petrick, Paul Salgo, James Stark BRO-tosynthesis Experiment:

Purpose/Problem/Question To determine how the rate of photosynthesis will change in relation to different types of white light.

Hypothesis Natural sunlight will yield the highest rate of photosynthesis, followed by fluorescent light, then incandescent light. Variables Independent Variable- The different kinds of light: Florescent, Incandescent, and Natural Sunlight. Dependent Variable- Photosynthesis or how much oxygen the plant is giving off. We used the amount of oxygen given off as a measurement of photosynthesis. Constant Variable- Sunlight was the constant/controlled variable.

Introduction Originally, our experiment was designed around five or six types of light. But after finding previous experiments on those topics, we were left to change our experiment. After researching, we found an experiment that would be appropriate. What kind of light is best for photosynthesis in plants. Florescent, Incandescent, or Natural Sunlight. Our hypothesis was that Natural Sunlight would work the best; after all, the oldest land plant was around 425 million years ago. Then we thought florescent light would be second best, because it’s quality is better than that of incandescent light. Incandescent light, we thought, would yield the least amount of photosynthesis, it is almost the opposite of quality “plant-light”.

Experimental Design Materials: 1 Fully grown pea plant (needs minimum of 3 leaves) 1 Fluorescent 60 watt light bulb 1 Incandescent 60 watt light bulb 1 Oxygen Gas Sensor w/ chamber 1 Stopwatch 2 Cardboard boxes 1 Computer w/ Logger Pro v3.3 1 GoLink Cable

Procedure 1.Lab Procedure: Take one of your two cardboard boxes and cut a small hole in the top, big enough to fit your light bulb. 2.Attach the Fluorescent light to the top of the cardboard box in whichever way necessary (we used duct tape) so that no outside light enters the box. 3.Repeat steps 1 and 2 with your second cardboard box except with the incandescent bulb instead of the fluorescent bulb. 4.To collect data, you will need to be able to plug your sensor into your computer. To do so, download Logger Pro v3.3 onto your computer and use the GoLink converter to plug the sensor into the computer. 5.Remove one leaf from the pea plant and place it in the Oxygen Gas Sensor Chamber 6.Place the chamber in the cardboard box with the Fluorescent light with the light turned off. (make sure there is no light in the chamber) 7.Let the leaf stay in the dark for exactly 4 minutes to prevent any photosynthesis for occurring. 8.When the 4 minutes are done, turn the light on. 9.Let the leaf sit in the light for 4 minutes and record the oxygen output with your Oxygen Gas Sensor. 10.Repeat steps 5-9 with the Incandescent light. 11.For the sunlight test, take either cardboard box and place it outside in the sun. 12.Place the chamber in the cardboard box with the light turned off. 13.Leave the leaf (inside the chamber) in the dark for 4 minutes. 14.When the 4 minutes are done, remove the cardboard box, place the leaf in the sun, and begin collecting data. 15.Record the oxygen output of the leaf for 4 minutes. 16.Compare data to see which light allows the most oxygen output.

Data

Analysis As most plants grow under sunlight, this is what they use for photosynthesis. One of the main byproducts of photosynthesis is oxygen. We decided that measuring the rate of photosynthesis would be easiest by measuring how much oxygen was produced when the plant was under the different lights.

Conclusion In conclusion, we found that photosynthesis in our plants was most positive when under florescent light. We predicted that florescent would be second to sunlight, but ahead of incandescent. Our actual results were: 1.Sunlight was best for photosynthesis. 2.Florescent being the second best for photosynthesis. 3.Incandescent showed a steady decline in photosynthesis.

Bibliography 1. AgHrt. "Light and Plant Growth." AgHrt 100 Lectures. 8 Mar phototropism and photoperiodism. Certain plants tend to exhibit a phototropic response, or bending toward the direction of the sun, due to the light- mediated breakdown of cellular auxins, chemicals that enhance cell elongation. 2.Photoperiodism, the induction of flowering, tillering, bulbing, etc., in response to day/night periods, is mediated by certain plant pigments known as phytochromes. "Light, Quality, Quantity." Environmental Factors Effecting Growth. 8 Mar Duration of light exposure. Rothenberger, Ray R. "Plant Lighting." Zone10. 8 Mar Plants and Light. A lot of Q&A. Vandre, Wayne. "FLUORESCENT LIGHTS FOR PLANT GROWTH." UAF. University of Alaska. 8 Mar Florescent Lights and Plants.