| Explore | We know that plants undergo photosynthesis in which they take in carbon dioxide and release oxygen in return. Plants also reproduce sexually and asexually, and some produce seeds and fruit. They are planted in soil and require sunlight and water/nutrients to grow. In class and background research, we have discovered how photosynthesis really works (the process and all elements involved), how water and nutrients travel in plants, and the role that plants have in the environment. We wonder how scientists manipulate the genes of plants to create new varieties and the different ways in which plants can be bred. Greentumble. (2019, September 02). How Do Plants Help the Environment. Retrieved October 16, 2020, from https://greentumble.com/how-do-plants-help-the-environment/ National Research Council (US) Committee on Identifying and Assessing Unintended Effects of Genetically Engineered Foods on Human Health. (1970, January 01). Methods and Mechanisms for Genetic Manipulation of Plants, Animals, and Microorganisms. Retrieved October 16, 2020, from https://www.ncbi.nlm.nih.gov/books/NBK215771/ Newton, J. (2019, November 22). What Is the Photosynthesis Equation? Retrieved October 16, 2020, from https://sciencing.com/photosynthesis-equation-6962557.html In our group's introductory agronomy experiment, we tested the water holding capacity and nutrient holding capacity of planting soil and park sand. We created a set-up with two cups, one with holes poked at the bottom and one intact that we layered outside of the cup with holes. We created two sets of those, each having a coffee filter to the first cup. We put planting soil in one and park sand in the other and proceeded to pour 200 ml of water into each. We hypothesized that the planting soil will have a higher nutrient holding capacity, meaning that less nutrients will leach out from planting soil. After we conducted the experiment, we found that our hypothesis was correct. The leachate from the sand was more yellow than that of the planting soil, meaning that more nutrients did leach out with the water. |
|---|---|
| Research Question | How will varying intensities of light affect the speed of growth of an Alfalfa medicago sativa plant? |
| Predictions | Given the variables, which are the intensities of light exposed to our plants, we predict that the plant with the most intense exposure to light will grow the fastest, while the plant with the least intense (dimmest) exposure to light will grow the slowest. We predict this will happen because, from our prior background knowledgeable of plants, we know that plants require sunlight exposure in order to undergo photosynthesis and produce glucose and oxygen from carbon dioxide and water. Limited sunlight would limit growth. Another possible outcome would be that the plants would grow at the same speed under varying intensities of light, meaning that light might not be a significant factor of plant growth. |
| Experimental Design | In this experiment we will compare the effects of different light intensities on the speed of growth of an Alfalfa medicago sativa plant. We will be using three different treatments (different light intensities) on the same type of plant. For each treatment we will keep the number of seeds, amount of soil, and amount of water used constant. We will plant 3 alfalfa medicago sativa flower seeds ½’’ from the surface of planting soil in a small pot. We will water each pot with 4 tablespoons of cold tap water every Tuesday, Wednesday, Friday, and Sunday at 10:00 a.m. and at 10:00 p.m. for the first 2-week period in order for the seed to bloom. For the remaining 2 weeks, we will increase the amount of water poured for each pot to 8 tablespoons of cold tap water every Thursday at 10:00 a.m. and at 10:00 p.m. The first pot will be kept in a dark space with no light. The second pot will be kept in a space with some sunlight covering the plant, giving it partial sunlight. The third pot will be kept outside with total sunlight covering it. On every Tuesday for 4 weeks we will measure the height (in centimeters) of each plant and record its color and shape. |
| Investigation Theme | AFW |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | California Academy of Mathematics and Science |
| Session | Fall 2020 |