Great Plant Debate
My 110 seventh grade science students at The Mott Hall School (IS223) located in the Washington Heights/North Harlem neighborhood of New York are still working on their experimental designs. I only see each class four times a week so it takes us awhile to get things done, but we're thinking, writing and drawing pictures. Just to get into the discussion I am sending along some ideas from a few of the study groups who have finished typing in their comments (there are about 28 in all). We still have to scan the drawings, which we will try to do on Friday. Tomorrow is open school day (and night) so things have been particularly hectic around here. One of the groups is concentrating on calculating the weight of the experimenal unit, as per the 25K constraint. They will be publishing their results soon, but it seems to them that if water has to be lifted, that 25K will be too low a limit. They'll explain. Some of the other groups are proposing various plants to grow. Over the next few days, we'll send along the work of other groups.
Regards, Susan Herzog
* * * * * * * * * Space Plants Plants have many needs in "earth-normal" conditions. They needs plenty of CO2, light, and water to do photosynthesis which produces its food. They also need some minerals from the soil for phosphate, nitrogen, and potassium to give them energy that they need. They also need soil for balance; it helps the plant anchor itself to the ground so it won't fall. Conditions in the space station differ from "earth-normal" conditions. This is because one big thing space station doesn't have is gravity. This may affect the water since it forms a ball (a typical energy form) and doesn't move up nor down. Another difference about conditions on the space station is that if the plants grew in light shining in a window, plants would receive a pattern of forty five minutes light, forty five minutes dark. That is why plants can only be grown under artificial light. In the space station there might not be enough CO2 for the plant to carry on photosynthesis. Daniel Leo, Geneciobel Rodriguez, Iliana Polanco, and Israel Matos * * * * * Earth Normal Conditions As scientists our group had decided that plants need the following things to grow: water, light, carbon dioxide, soil, plant food, and environment similar to their own. The plant needs water, light, and CO2 so that it can carry on photosynthesis. The Radish needs soil so it can be held in place and receive water and dissolved nutrients through the roots. The plant needs food so it can get the nutrients it needs. The Radish needs an environment similar to the temperate climate it is adapted to on earth, so it can become bountiful and grow faster. Growing Plants in Space The plant our group will be using is: The Cherry Belle Radish. We chose the radish because: it is a food plant, it germinates quickly, it needs little soil, and it grows quickly. We chose the Cherry Belle Radish specifically because: it is leafy and will therefore be an active photosynthesizer and so will give off a lot of oxygen. To water the plant we are going to use a water pump. The water pump will pump water into a tube which will water the plant (see illustration). To refill the pump there will be a little hole on the side that would enable water to get to the plant. The pump will be clear so it will be easy to tell if the pump needs to be refilled. We are aware that the plant will need certain nutrients such as: nitrogen, phosphorus, and potassium, so plant food will be mixed in the water before it leaves the Earth. Artificial light will be left on for 12 hours. We need artificial light because in the space station there is 45 minutes of light at a time. We won't be needing heat because radishes grow best in cool weather. The fact that they grow in cool weather blends in well with the cabin temperature. Another good reason why we chose the radish is because: it is a root plant and we have learned that root growth is very much affected by gravitropism. It would be interesting to find out how the root will grow (for instance will it have the same shape as a radish grown on earth) without gravity. Shawna, Shirley, Daniel, and Justin * * * * * Plants Needs in Earth & in Space Plants need several things to grow in Earth's normal conditions. In order to know what is needed to grow plants in space, we first need to know what plants need in Earth and what differs in space. In Earth's normal conditions plant needs may vary. But mostly all that plants need is water and light. Plants that get their energy from photosynthesis also need carbon dioxide to go through this process successfully. Plants also need minerals such as nitrogen and nutrients and vitamins from the soil. Differences and constraints in space are the light and microgravity. The problem with light conditions in space is if one leaves the plant on the space shuttle's window, the plant would get 45 minutes of light following by 45 minutes of darkness. Plants definitely need about more than 9 hours of light in order to go through photosynthesis. So the light that the plants will get will be artificial. The constraint with microgravity is that in the act of watering the plant, water will form a sphere and not "fall" if not under constant pressure. So these are some things that scientists will have to consider while working on this experiment. For my group's design we chose the sunflower dwarfs because the seed that the sunflower produces has many nutrients and many people eat it because it tastes good. We also chose the sunflower because they are pleasant to keep at home and in the space shuttle. We chose a dwarf variety because of space constraints. Silvia Falconi, Jessy Trejo, Amarillis Estrella, Carlos Jimenez * * * * * * * Growing Plants in Space On the earth, plants need many different resourses to survive. All plants need water. Water is used during the process of photosynthesis and given off during respiration. Light, like water, is also used during the process of photosynthesis. The light would usually come from the sun and in some cases artificial light is used. Another plant need, on earth, is carbon dioxide which is also used during photosynthesis and given off during respiration when oxygen is needed by the plant. During photosynthesis molecules of carbon dioxide and molecules of water are added together. When added together light provides energy for the entire process of photosynthesis. The photosynthesis afterwards produces a simple sugar and oxygen. During respiration oxygen combines with sugar to release carbon dioxide, water and energy in the form of ATP. The energy in ATP can then be used by a plant for life processes. In the space station the conditions of the plant growth differ in many different ways. The water would be difficult to get into the soil. Another difficulty is the carbon dioxide. To provide the carbon dioxide the astronauts would have to make a mechanical pump to pump in the carbon dioxide. This design shows all of the materials needed for the experiment. The box is a straight cube with the right amount of soil. At the top are eight three foot long bulbs. On the side are two mechanical pumps, one for carbon dioxide and the other for water. The kind of plant that is wanted to be used is a cactus plant. This kind of plant was chosen because it doesn't need a lot of water. Some kinds of cactus can hold two years worth of water in their stems. By the JASPM group * * * * * * Growing Herbs in Space We chose to grow herbs because herbs are leafy and are low growing. Herbs carry on photosynthesis in the process of which they produce oxygen gas that can be added to the air in the crew quarters. Some herbs can be used in cooking and as medicine. In our experiment we are going to put two tubes into the soil, one for the water and the other with an air filter (excess carbon dioxide in from crew cabin and excess oxygen out from plant environment). We are hoping that through the tubes the water and the gases will get into the soil. We are not sure how water will seep through soil in microgravity. The tubes will be attached to the container so that it will be hard for the tubes and the plant to escape the container in microgravity. The kind of light we will use will be incandescent because it gives off the most heat. We hope this design will help you or give you ideas to grow plants in space. Anthony Ho, Stephanie Guichardo, Juan Carlos Medrano, Vanessa DeLaRosa * * * * * We Chose Flowers for Beauty and Oxygen We chose to grow a flowering plant for it's beauty. One of us chose a Woodbine and another person chose Violets. We are going to use magnets to hold down the plant growing container and the water reservoir. An "absorber" will connect the plant growing container and the water reservoir. The "absorber" will take the water to the plant. This process is called wicking. Light: For this experiment a lamp will be provided with eight fluorescent bulbs of 40 watts with each. This is equal to 320 watts. This is only about one fourth of the power provided in the constraints. Keila Fernandez Andy Cabrera Joseida Rosario Class 7-703 * * * * Growing Cotton Plants Information Plant Identity: Cotton Plant Facts: Cotton plants grow where the weather is warm. Such as, in Texas or Mississippi. These plants are called annual plants. In hot tropical areas, such as, Burma, India, and in parts of South America, cotton plants will grow year after year and they may grow to be the size of a small tree. Those plants are called perennial plants. Process: In the process of cotton plants growth, white flowers may appear on the bottom branches. Then, they drop off and leave a green boll, which contains the cotton. When the boll is fully grown, it pops open exposing the cotton fibers and seeds. Diagram Caption Caption: Our plan is to have a plastic container, cotton plant seeds, water, a carbon dioxide tank and a lamp (containing a 75 watt bulb, regular). Directions: Place the seeds in a plant pot. Then, put the plastic container over them and form holes to transfer the carbon dioxide to the cotton plant. Place the light over the plant about 12 hours a day (substituting for the sunlight). After finishing all these directions, attach the container to the wall with gray rubber band tape, to keep it from moving, if the space station fires a rocket or is impacted by the space shuttle when it docks. Marlene Rijo, Valerie Jean, Joshua Yoo, James Freeman