| Explore | We know how photosynthesis works and what factors go into it. We know that chlorophyll in the plants reflects green making plants appear green to our eyes. We know that changing different factors has an effect on the rate that photosynthesis occurs in plants. |
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| Research Question | Does the rate of photosynthesis change when leaf disks are placed in different liquids? |
| Predictions | Yes, rate of photosynthesis will change, it will be much faster in gatorade and much slower in milk. -The disks in Gatorade will float the fastest. -The disks in milk will float slower or not at all. - The disks in juice will float but much slower than in the water. |
| Experimental Design | Independent Variable: Liquids that the disks are placed in. Dependent Variable: Rate of photosynthesis. Control Group: Water+baking soda cup. Procedure: 1. Prepare the cups. Label four cups for the different liquids. Label cup one Water, cup two Gatorade, cup three milk, and cup four juice. 2. Fill each cup with 90mL of the corresponding liquid. Add 1/2 scoop of baking soda to each cup. Stir. 3. Prepare 40 leaf disks (10 disks per cup). Refer to leaf disk lab for preparation directions. 4. Place the leaf disk back in their corresponding cups and place under light. All disks should sink to the bottom of the liquid. 5. Record observations (number of floating disks) in a data table every minute for 15 minutes. 6. Repeat experiment once more for a second trial. |
| Conclusion | During our experiment, we found different things. First we started with the normal solutions and we struggled to get the leaf disks to sink in the syringe so we started using a diluted solution that was 9 parts of the original liquid and 1 part water. After the 15 minutes we had 0 leaf disks floating in water, 8 in Gatorade, 3 in juice. All 10 leaf disks in milk floated from the beginning of the experiment. Photosynthesis occurred at the fasted rate in Gatorade. A possible explanation as to why none of the leaf disks floated in water but they did in past experiment is because in this experiment we used tap water while in other ones we used distilled water. Distilled water is a type of purified water and is usually ideal to use on plants. Plants photosynthesize the fastest with pure water, and since the juice has so much added sugar it would take a long time for photosynthesis. The plant would have to filter through all of the impurities. Similar with Gatorade, the plant would have to filter through all the sugar. But since Gatorade has ingredients like vitamin K, vitamin C and potassium, it was able to carry out photosynthesis by these are nutrients that are also commonly found in fertilizers. The milk was not able to photosynthesize at all because it had such a low water content compared to all the other liquids. To expand on results, we could experiment on more liquids to see if we find the same thing. We could also do solutions that are a lot more diluted, like possibly 1 part liquid and 9 parts water. |
| Investigation Theme | POS |
| Grade Level | High School Students (Grades 9,10,11,12) |
| Teacher Name | Erica Shannon |
| School Name | Elkhart High School |
| Session | Fall 2021 |