| Explore | From our experiences outside of school told us that plants need water and sunlight to grow, and that plants release oxygen. We discovered that in class that plants need carbon dioxide as well, and in the process of photosynthesis plants produce sugars. One specific question that interested us about plants is why does photosynthesis not occur in freezing temperatures? |
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| Research Question | We wanted to test the effects of different temperature water on plants and if photosynthesis would occur. We wanted to test temperatures from hot to freezing cold to room temperature. We thought of this question because it interested us and the question relates to the real world. It fits the topic because in class we were studying the photosynthesis in general. |
| Predictions | Possible outcomes of our studies given the variables we were working with are that the cold would slow the process of photosynthesis. Another would be that the hot would speed up the process of photosynthesis. We thought these were outcomes because the cold would simulates winter. During winter, the plants go into a dormant state. The hot would be mimicking summer, in summer the climate is warm and there is a lot more sun. Sunlight would be needed for photosynthesis. |
| Experimental Design | Our research plan for our project was to see how temperature affects photosynthesis. We tested three different temperatures of water: hot, cold, and room temperature. Hot water was 30 degrees Celsius to start. Cold water was 20 degrees Celsius to start, and room temperature was 25 degrees Celsius to start. They mostly remained constant, but we kept track if they changed. Using the vacuuming method with syringes to remove air from the leaf disks we got from spinach leaves, we wanted to see if they could float in the different temperatures of water. To start they all sunk because we vacuumed the air out with the syringes. Due to the process of photosynthesis oxygen bubbles formed around the disks and they floated because they produced oxygen. We know it wasn't carbon dioxide because CO2 dissolves in water. We looked for results every two minutes for twenty minutes. We observed the amount of disks floating and each water temperature. The constant variables when conducting our experiment was the amount of water, light and leaf disks. We then proceeded to record our data in a data table and plot it on a line graph. |
| Conclusion | We can make the claim that when exposed to colder water or climates, the process of photosynthesis tends to slow down or even stop completely. Some possible explanations for our results may be that during our vacuum process, we may have damaged some of the leaf disks in the cold water which would cause them not to respond to the investigation properly. Also, an explanation may be that photosynthesis does not occur in cold water because it is like the winter where many plants die or fail to grow. Our result support our claim because during our experiment there were no leaf disks floating in the cold cup, which proves that photosynthesis did not occur. In the future, we will plan to possibly expand the range in temperatures between the cold and hot waters. |
| Investigation Theme | POS |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | Arthur L. Johnson High School |
| Session | Fall 2017 |