| Explore | We know that plants photosynthesize. We know that the mass of a plant comes from photosynthesis. We discovered that photosynthesis can happen even when a leaf is not connected to a plant. Plants' ability to photosynthesize interests us. |
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| Research Question | How does changing the plant we create leaf disks from affect the rate of photosynthesis? |
| Predictions | We think that the spinach leaf disks will float before the rhododendron leaf disks. We think this because spinach leaves are thicker (as opposed to rhododendron leaves), which means there are more chloroplasts to photosynthesize, which means they will release oxygen quicker, and therefore will float sooner than the rhododendron leaf disks |
| Experimental Design | Step one: create leaf disks out of rhododendron leaves and spinach leaves. 3 disks per leaf type. Step two: Prepare baking soda and water solution and infiltrate leaf disks using the same method as the leaf disk lab, but use 50 ml beakers instead of plastic cups, and 40ml of water per beaker. Prepare only two beakers (both with baking soda solution) using this method. Step three: Place spinach and rhododendron leaf disks in separate beakers with the baking soda and water solution. Place these cups under a lamp, 3 – 5 cm away from the lamp. Step four: Turn lamp on, start stopwatch. Record the amount of floating and not floating leaf disks in each cup every minute. When all leaf disks have risen in each cup, stop recording. |
| Conclusion | We found that the rhododendron leaves rose quicker than the spinach leaves. This answers our research question in that different plants photosynthesize at different rates, as if they photosynthesized at the same rates, every leaf disks would rise at the same time. We had no problems, but we noticed that one leaf disk rose, then the next minute fell, then the next minute rose again. This did not affect our results as the rhododendron leaves rose marginally faster than the spinach leaves. |
| Investigation Theme | POS |
| Grade Level | High School Students (Grades 9,10,11,12) |
| Teacher Name | Jacqueline Ellig |
| School Name | Lynden High School |
| Session | Fall 2023 |
| About this Project | I think that this team did a great job of engaging with scientific thinking. You can easily follow their questioning and decision-making process throughout the development and execution of their experiment, while engaging with the scientists who were involved. -- Meghan Britton, Liaison |
