| Explore | 1. - They use photosynthesis to grow and receive nutrition - Dandelions steal water from plants - Many factors affect the successful germination and growth of a seed - They compete for resources and can emit a toxin to keep other plants away - Some plants contribute oxygen. - There are more than 80,000 types of edible plants 2. Different seeds need different kinds of light They have photosensitive pigments that tell them when it’s sunny If they are too deep in the soil, they can’t receive enough light and won’t grow Our everyday plants grow at varying temperatures depending on their location Seeds need oxygen so if they are too deep in the soil they can die Light, Space, and nutrients are all main factors in a seeds germination 3. “What stand-out physical things change in the seed when they don’t get the light that they need?” “How does the amount of time for the seed to germinate change when it develops in a different type of light or not enough?” |
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| Research Question | We want to study how light affects the germination of a seed. Our question is, “Is a seed’s germination affected by light?” We chose this question because we are curious about the effects of light during seed germination. We already know that seeds need oxygen and need different types of light. We also know that some seeds need it to be dark to germinate and some need a lot of light. |
| Predictions | Given our study question, we will experiment with putting seeds in different light situations and we can expect that our outcome will be growth changes, physical changes, or the time it takes for the seed to grow. We think that an obvious explanation is that due to the changes in the light, our seeds will develop different and unexpected features. This could happen because of the different kinds of light or being in the dark. All seeds are said to need three things: water, light, and nutrition. If we change one of those factors, we can almost assure an unanticipated change in the seeds' growth. |
| Experimental Design | Our plan is to find the seed that we will want to experiment with, and then create an environment that is different to its usual ecosystem. For example, if it's a seed that needs a lot of light, we will but it into a dark box. |
| Conclusion | To conclude this experiment, I believe that the time each seed spends in a certain amount of light affects the germination tremendously. We learned that seeds grow a lot in the dark over the first few days of their germination. But after a few weeks, they stop growing because they can’t photosynthesize. Seeds that are constantly in the sun, won’t germinate for the first few weeks but will grow a lot later on. We think this is because, since the seeds in the sun aren't underground or in the dark, they need to acclimate to their environment before they can grow. Overall seeds can grow in both sunlight and in the dark but it depends on the amount of time they are in the light or the dark. To connect this to the real world, you should plant your seeds deep in soil, and then once they grow move them to the sun. DO NOT put your plants in a pot in the middle of a room when they begin to germinate because it makes it difficult for them to photosynthesize. In the future we would measure our seeds growth more often to have a larger range of data. We would also change the factor of light, to light → dark and change the factor of dark, to dark → light. This is based on the above data. We would also keep our control of sunlight, but to get a larger range of data, we will use 2 petri dishes per factor. We also had an unexpected outlier which was our control. It was in the middle of a room for the whole experiment. Throughout the weeks, it grew 1-2 cm every 3-4 days. By the last two weeks of our experiment the seeds began to turn black and stopped growing at all. We did not see any epicotyl growth or photosynthesis from our control experiment which made this an outlier. We are disappointed to note that human error was present. The time away from school during our outdoor trip and spring break kept us from measuring results and following our plan for our experiment. We will count this as Human Error. It may have changed the conclusions that we drew from our experiment. Because we were inconsistent with our watering, and did not follow our schedule, our experiment is non-replicable. Something I want to learn more about is does changing the types of seeds affect how they grow in the sun/dark? Because we noticed that our seeds got dry I wonder, If we watered less, would the seeds dry out more in the sun? Would they stay more moist if they were in the dark? We also saw humidity in the petri dish that was in the sun so I wonder, did the direct sunlight cause humidity in the petri dishes? And If so, how did this affect the seeds' germination? To close this experiment I want to know, If we replicated this experiment in a tropical location, would this change our results? In the next experiment we hope to answer some of our questions, and hopefully create an accurate and replicable experiment that fully represents how light affects the germination of millet seeds. |
| Investigation Theme | WOS |
| Teacher Name | Jeff Porter |
| School Name | San Francisco Friends School |
| Session | Spring 2023 |