| Explore | We know plants need soil to grow, and sunlight. There are lots of kinds of plants and you can eat some but not others. We are interested in the effects of dog pee on photosynthesis, because our neighbor gets mad when the dog pees on the lawn, causing brown spots. |
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| Research Question | How does salt levels affect photosynthesis? |
| Predictions | We predict that the highest salt concentration will have the least amount of photosynthesis. We think this will happen because we see things that have high salt kill grass. Plants can't be watered with sea water for this reason. |
| Experimental Design | We will use the leaf disk assay with spinach to test our research question. We will use three treatments: no salt, 2% salt and 4% salt. We are thinking about how to set up the leaf disks- should we put each disk in a separate cup or put all the disks together? We want to do a total 10 disks per treatment. Also we want to know your suggestion for taking time points, should we record each float event or take count by minute passing? We will baking soda (2% solution) to each treatment and place them under the light. We are doing these experiments in replicate ( with 10 disks per cup). |
| Conclusion | From our lab we learned that our hypothesis was wrong. We thought that the water without salt in it would cause the leaf disks to float more quickly than the water with salt in it. We thought this because dog pee kills grass, and dog pee is salty. Instead, we saw in our data that the saltiest water (4% salt) had disks that floated the fastest. We can conclude that it's not the salt in dog pee that stops photosynthesis- it must be something else. We would have to do further experimentation to figure out what else in the dog pea stops photosynthesis. |
