| Explore | We know that plants need sunlight, water and carbon dioxide to go through the process of photosynthesis. Photosynthesis is a process that plants go through to create their own food. We also know that oxygen and glucose are products of photosynthesis. We have discovered that bubbles will surround the leaves. The bubbles are the oxygen that is produced by the photosynthesis that is taking place. We know the bubbles are oxygen because it does not dissolve in water. The bubbles would make the leaf disks float and that's how we know that they went through photosynthesis. The questions that interest us are, How long does a plant need for it to go through photosynthesis? When do trees know when to stop photosynthesizing? The question we ended up testing for was “Will the different color of the leaf disks affect the rate of photosynthesis?” |
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| Research Question | We want to test if the different coloring of the plants would affect their rate of photosynthesis. We came up with this question because the first experiments (carbon dioxide and light vs. dark) only had one type of plant, spinach, so we reflected the results of those experiments and considered other possible experiments. This made our group come up with the idea to use different kinds of leaves of different colors to see if that would have a change from our original results. |
| Predictions | Possible outcomes of the study based upon the variables we are using will either support the fact that the darker leaf disks will float faster. Or, our hypothesis and predictions will be rejected after we run our experiments to test our ideas. Based on our previous knowledge, we know that having carbon dioxide solution within the water cups, also having light present, causes photosynthesis to occur, making oxygen bubbles appear in order for the leaves to float. We are predicting that the darker kale leaves will float faster than the lighter color spinach and kale leaves. |
| Experimental Design | Our plan is to have 3 cups, all containing the same amount of water and the same amount of baking soda solution in each, containing .2% baking soda. Then we are to cut out the leaf disks from all three kinds of leaves, the dark kale, light kale, and spinach, making sure to avoid stems and big veins. After going through the precise vacuuming procedure that we learned from previous experiments, we put all of the leaf disks to their appropriate cups. Those cups, containing the leaf disks, are then put underneath a light source, ours being a lamp, all equidistant from the lightbulb. A timer will begin as soon as the light is on, and on every minute-mark that goes by, the number of leaf disks floating and not floating in all cups will be recorded into a data table. We will be testing whether or not the type of leaf disk it is will affect the rate of photosynthesis. We will measure the amount of water being placed into the cups and the amount of baking soda solution used. We will observe whether the leaf disks float over time or not and we will observe tiny oxygen bubbles forming around the leaf disks as photosynthesis takes place. Variable that are kept constant throughout the experiment will be the amount of water, amount of baking soda solution, the amount of leaf disks, the cups used, and the light source. In order to record the data a group must have a data chart ready before the experiment has begun. The chart must have 3 columns, one for each kind of leaf. Within those columns must indicate two separate sections that shows the amount of leaf disks floating versus the amount of the non-floating leaf disks. For every minute that goes by, there should be a row under each column to say how many were floating and how many were not at that minute-mark within all 3 cups. |
| Conclusion | We can conclude that the thickness and the color of leaves affect the rate of photosynthesis. Some possible explanations for our results is that because of the over vacuuming of the leaf disks, possible ruining their structure, they failed to rise. Also the kale leaf disks may need more carbon dioxide since they are more dense than the spinach leaf disks. Our data collected supported the claim because as shown in the data, the kale leaves didn’t have a rising rate of photosynthesis since they were so thick. In the future we could use other leaves to see if it was a fault in the experiment or the kale is just too heavy to float. |
| Investigation Theme | POS |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | Arthur L. Johnson High School |
| Session | Fall 2017 |