| Explore | Photosynthesis is the process in which plants use sunlight to produce foods from carbon dioxide and water. The equation for photosynthesis is the following 6CO2+6H2O --> C6H12O6+6O2. This shows how much of each component is being used while it is happening. This process involves chloroplasts and the pigment of chlorophyll, and also generates oxygen. Our independent variable is using ultraviolent radiation to speed up the rate of photosynthesis. We picked UV radiation because plates uses the sun light to break down the carbon to make the C6H12O6 we think that a more powerful radiation will help break it down faster. Ultraviolet light is a type of electromagnetic radiation, as are radio waves, infrared radiation, X-rays and gamma-rays. UV light, which comes from the sun, is invisible to the human eye. It makes black-light posters glow. In class we did this floating leaf procedure and in the procedure we had three cups and a syringe; In the three cups there was regular H2O, water with CO2 (breath), and water mixed with baking soda (another source of CO2), we used the syringe as a vacuum to open up the Stamata so they can absorb the CO2. Throughout the 25 minutes of the procedure none of the leaf discs floated, we believe it was our light source; we believe if we switched our light the leaf would have floated because when the leaf goes through the process of photosynthesis which it produces glucose and oxygen, which explains why the leaf's floated. we measured the rate of PS when the leaf floated to the top. (Ensminger, Peter A.) "Photosynthesis." The Gale Encyclopedia of Science, edited by K. Lee Lerner and Brenda Wilmoth Lerner, 5th ed., Gale, 2014. Science in Context, link.galegroup.com/apps/doc/CV2644031715/SCIC?u=lakeorion&xid=4df52e16. Accessed 20 Apr. 2017. Ensminger, Peter A. "Plant pigment." The Gale Encyclopedia of Science, edited by K. Lee Lerner and Brenda Wilmoth Lerner, 5th ed., Gale, 2014. Science in Context, link.galegroup.com/apps/doc/CV2644031746/SCIC?u=lakeorion&xid=67f85bf8. Accessed 26 Apr. 2017. Haycock, Dean Allen. "Radiation exposure." The Gale Encyclopedia of Science, edited by K. Lee Lerner and Brenda Wilmoth Lerner, 5th ed., Gale, 2014. Science in Context, link.galegroup.com/apps/doc/CV2644031853/SCIC?u=lakeorion&xid=dda27bc6. Accessed 26 Apr. 2017. "PlantingScience - Resources: The Power of Sunlight ..." N.p., n.d. Web. 25 Apr. 2017. "Investigating Photosynthesis Lab." Google Docs. Google, n.d. Web. 26 Apr. 2017. |
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| Research Question | How would UV light affect the rate of photosynthesis? |
| Predictions | We think that it wont work with in our time range (25-30 minutes), but if its longer than our time range then it could possibly work. Null Hypothesis: Any differences between the number of leaf disks floating in the UV radiated cups and the control are due to random chance. |
| Experimental Design | 1. Place four cups with about 2 cm of distilled water, a pinch of baking soda, and 12 hole punched leaf disks in each up (we will use the syringes to make sure that they all sink, just like we did for the leaf disk experiment). 2. Place both cups in a light box with an LED UV light hovering over it. Both cups will be placed equidistant from the light. 2. Check in on it every 5 minutes for a span of about a half hour, and see how the rate of photosynthesis is effected by the UV light. We will examine this by seeing how fast the leaf disks come up to float. 3. We did 4 trials (cups), and we also did a control trial the next day. This just included water, leaf disks, and baking soda, we tested it for the same amount of time (30 min) and checked it every 5 minutes just like with the radiated cups. We modified our light box as well. We put one regular bulb at the top of the box and hung it over the control, so that it would be more neutral than our radiated cups. we did our control a second time this time with a different light bulb, we had much better results the first 5 minutes we had 4 floaters and at the end of 30 minutes we had all 12 floaters. Materials Needed: UV light bulb, cups, baking soda, water, light box, stirring sticks, leaves, syringes, an index card, hole punch, cotton swabs (q-tips), possibly soap |
| Conclusion | If plants are exposed to UV radiation for at least 30 minutes, then the rate of Photosynthesis will increase. This hypothesis was not supported. After 30 minutes with 4 trials there were no results of any leaf disks floating with the UV light for the independent variable; however, with a 40 WATT soft incandescent light bulb used on the control part of the experiment, there were 4 leaf disks that floated in 5 minutes. In 10-25 minutes there were 11 that floated, and in the last 5 minutes, all 12 leaf disk were floating. The data displays that the UV radiation will have no effect on the plant due to the fact that there is a certain pigment in the leaf disks that will in fact, block out the UV rays. The experiment had a p value 3.2, so the null hypothesis is rejected. There is a 95% confidence level showing that there is a difference the rate of photosynthesis had within the UV light and our control light. |
| Investigation Theme | POS |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | Lake Orion High School |
| Session | Spring 2017 |
