Tomatosphere: Space Gardening (Adapted by: Nandita Bajaj from Tomatosphere.org) Background Mars, our neighbouring planet has been the object of our fascination for as long as space exploration began over 50 years ago. So far, three robotic rovers have been successfully sent to Mars for remote exploration and have yielded tremendous results about the Red Planet. However, sending humans to live on Mars is a very real mission of the Mars One project. Traveling to and from Mars could take in excess of two years. It is imperative to know how to grow food while on the journey to the Red Planet, the time spent on Mars and on the return journey. Tomatosphere is a science project that was launched by the Canadian Space Agency along with other sponsors to explore the growing of food in space. This year, the project will utilize the 600 000 tomato seeds that were taken to the International Space Station (ISS) on board the very last US shuttle in July of 2011 and returned to Earth with Commander Chris Hadfield in May of 2013. In total, the seeds spent approximately 22 months on board the ISS. Figure 1: CSA Astronaut Dr. Robert Thirsk with the Tomatosphere seeds on board the ISS Figure 2: Tomatosphere seeds float in front of a window on the ISS. The blue line in the background is the Earth s atmosphere. The goal of this science experiment is to determine how well the space seeds will grow on earth compared to the seeds that have not been in space. The results from our science experiments will be shared with the Tomatosphere team and will help Canadian scientists to understand some of the issues related to long-term space travel. The Scientific Method The Tomatosphere Project is a scientific investigation in which the germination properties of seeds are examined. Based on the outcome of this investigation conclusions will be drawn which will facilitate the planning of long term missions on the International Space Station, to the Moon and eventually, to the planet Mars. The Scientific Method will be used for this investigation. Step 6: Drawing Conclusions/ Creating a Theory Step 1: Posing a Question based on the known theory Step 2: Developing a Hypothesis Step 5: Making and Interpreting Observations Step 3: Designing an Experiment Step 4: Controlling Variables Step 5: Performing the Experiment Adapted by: Nandita Bajaj (Northview Heights Secondary School) from Tomatosphere.org Page 1
Pre-Planting Step 1: Posing a Question based on the known theory Known Theory: What background information is available about the Tomatosphere project? List all pieces of information that will be helpful in posing a good scientific question. A good scientific question can be answered by observation, or evidence. Purpose of project: The purpose of this project is to compare the germination of two types of seeds (one set that has been in space and another set that has not been in space). The results will help Canadian scientists understand some of the issues related to long-term space travel. Meaning of germination: A seed can be considered to have successfully germinated when two (2) distinctly separate cotyledons (embryonic leaves) can be seen. This process will usually take place between 5 and 20 days depending upon local conditions. Requirements for successful germination: Seeds require water, sunlight, and a warm temperature to germinate. Tomato seeds usually germinate between 5-7 days. Scientific Question: Pose a few questions that would be helpful in comparing the germination of the seeds during the course of the experiment. Word questions in a way that allows them to be answered by an investigation or experiment. Be sure that the question identifies a relationship or factor you can investigate 1, such as: percent of germination: Will a greater number of tomato seeds that have been in space germinate compared to the number of tomato seeds that have not been in space? rate of plant growth: Will the tomato seeds that have been in space grow faster than the tomato seeds that have not been in space? health of plant (height, colour, flowers etc.) Will the tomato seeds that have been in space grow taller than the tomato seeds that have not been in space? Will the tomato seeds that have been in space have a brighter colour than the tomato seeds that have not been in space? Will more of the tomato seeds that have been in space bear flowers compared to the tomato seeds that have not been in space? 1 Excerpted from Prentice Hall Science Explorer Resources Pro CD-ROM 2000 Pearson Education Inc., publishing as Pearson Prentice Hall. Used by permission. Adapted by: Nandita Bajaj (Northview Heights Secondary School) from Tomatosphere.org Page 2
Pre-Planting Step 2: Developing a Hypothesis A hypothesis is a prediction about the outcome of an experiment. A properly worded hypothesis is in the form of an If then statement. In science, hypotheses must be testable. That means that researchers should be able to carry out an investigation and obtain evidence that shows whether the hypothesis is true or false. Develop a hypothesis for the following variables in the Tomatosphere experiment. percent of germination: If tomato seeds are exposed to 22 months of a micro-gravity environment in space, then more of these seeds will germinate compared to tomato seeds that have not been in space for the same growing conditions. rate of germination: If tomato seeds are exposed to 22 months of a micro-gravity environment in space, then these seeds will germinate faster compared to tomato seeds that have not been in space for the same growing conditions. health of germination (height, colour, flowers etc.) If tomato seeds are exposed to 22 months of a micro-gravity environment in space, then these seeds will grow taller compared to tomato seeds that have not been in space for the same growing conditions. If tomato seeds are exposed to 22 months of a micro-gravity environment in space, then these seeds will have a brighter colour compared to tomato seeds that have not been in space for the same growing conditions. If tomato seeds are exposed to 22 months of a micro-gravity environment in space, then more of these seeds will bear flowers compared to tomato seeds that have not been in space for the same growing conditions. Adapted by: Nandita Bajaj (Northview Heights Secondary School) from Tomatosphere.org Page 3
Pre-Planting Step 3: Controlling Variables Every experiment involves several variables, or factors that can change. Identify the variables in the Tomatosphere experiment based on the provided definitions. The variable that is purposely changed and tested is called the manipulated variable or independent variable. Which variable(s) in the Tomatosphere experiment is/are independent? The microgravity environment of space to which one set of tomato seeds is exposed is the independent variable. Since all data will be collected over a period of 4 weeks, time is a common independent variable to both seeds. The factor that may change as a result of the manipulated or independent variable is called the responding variable or dependent variable. Which variable(s) in the Tomatosphere experiment is/are dependent? The health conditions of the space-based seeds, such as percentage of germination, rate of germination, health of germination (height, colour etc.) are the dependent variables. An experiment is not complete unless the experimenter controls all other variables. Controlling variables means keeping all conditions the same except for the manipulated or independent variable. Which variable(s) in the Tomatosphere experiment is/are controlled? The controlled variables are the environmental conditions within which the two sets of seeds are grown: amount of sunlight, amount of water, location, amount of soil, type of soil etc. In a controlled experiment, scientists usually study two types of groups experimental group and control group. The experimental group is the group whose conditions are being changed. The control group, or the control, is the group whose conditions are not being changed. Which group in the Tomatosphere experiment is the experimental group? The group of seeds that have travelled into space for 22 months makes up the experimental group. Which group in the Tomatosphere experiment is the control group? The group of seeds that have not travelled into space makes up the control group. Adapted by: Nandita Bajaj (Northview Heights Secondary School) from Tomatosphere.org Page 4
Planting Step 4: Designing the Experiment Obtain the materials: List all the materials needed to perform this experiment properly. T seeds (15): 1 per pair V seeds (15): 1 per pair Tray with cover (2): 1 tray for the T seeds and 1 tray for the V seeds Labels for trays (2): 1 for the T tray and 1 for the V tray Peat pellets (15): 1 per pair Wooden pencil with an eraser Ruler (2): 2 per class Warm water supply Forceps/tweezers Dixie cup - small (1) (85 ml) Popsicle sticks for seed labels (30): 15 for T seeds and 15 for V seeds Plan the procedure: List all the steps of the procedure needed to perform this experiment properly. Watch the following video to learn about the proper way to water a peat pellet and to plant the seed: https://www.youtube.com/watch?v=rqnnmgb61jc Plant the T seeds Steps 1-4 will be performed by the teacher. 1. Place all the peat pellets in the tray such that they are even spaced throughout the tray. 2. Slowly pour 85 ml (1 small Dixie cup) of warm water into each peat pellet. 3. Let all the peat pellets expand to their full size, which is 3 in height. 4. Carefully drain out excess water from the tray to minimize fungal problems in the plant. Steps 5-13 will be performed by the students (in pairs) 5. Obtain the following materials from the teacher: 1 moistened peat pellet, 1 T seed, 1 coloured flag to label the seed, 1 wooden pencil with an eraser, a pair of forceps 6. Carefully pull back the netting from the top of the pellet to gain access to the soil. 7. Using the eraser side of the wooden pencil, carefully stir the soil at the top to allow it to aerate. 8. Using the eraser side of the wooden pencil, poke a 1/8 deep hole (height of the pencil eraser) in the middle of the soil. 9. Using a pair of forceps, place the T seed in the hole. 10. Using the eraser side of the pencil and your fingers, gently cover the seed with the soil. 11. Label your flag such that it is easily identifiable and insert it on the side of the peat pellet. 12. Take your labeled pellet to your teacher. Steps 14-15 will be performed by the teacher. 13. Place all the labeled peat pellets in the tray labeled T such that they are even spaced throughout the tray. 14. Cover the tray by placing the plastic dome on top of it. 15. Place the tray in a warm sunny area that will receive a lot of sunlight and warmth. If possible, provide a constant source of fluorescent light to the seeds by leaving the lights on all day till the end of the experiment. In addition, if additional heat can be provided to keep the soil warm by turning on the radiators to low heat, seeds will germinate more easily. Plant the V seeds 16. Repeat steps 1-15 for planting the V seeds. 17. Ensure that the V tray containing the planted V seeds is placed in the same location as the T tray in step 16. See Figure 3 below. Perform the experiment: Follow steps 1-17 to perform the experiment. Figure 3: The V tray and T tray setup under identical conditions. Adapted by: Nandita Bajaj (Northview Heights Secondary School) from Tomatosphere.org Page 5
Post-Planting Step 5: Making and Interpreting Observations During a scientific investigation, you make observations and take measurements that are called data. Several methods can be used to collect and interpret data in a meaningful way. There are two types of observations that can be made: Qualitative Observations: Observations that require the use of the five senses and describe the quality of the variable being observed. For example, the liquid is blue and shiny; the gas smells pungent; the carpet is rough, etc. Quantitative Observations: Observations that describe the quantity (number, amount, distance, etc) of the variable being observed. For example, there are 28 students in the class; the beaker can hold 250 ml of fluid, etc. List all the dependent variables in the Tomatosphere experiment that are qualitative in nature. whether the seed germinates; colour of the plant; whether the plants get flowers List all the dependent variables in the Tomatosphere experiment that are quantitative in nature. height of the germinated plants Creating Data Tables A data table is an organized arrangement of information in labeled rows and columns. In science, data tables are particularly useful when you record observations during an investigation. Planning a data table is an important part of designing an experiment. Some tips for creating data tables are listed below 2 : Personal Data Tables Consider the independent and dependent variables to determine what observations you will be making. Which variable(s) in the Tomatosphere experiment is/are independent? The microgravity environment of space to which one set of tomato seeds is exposed is the independent variable. Since the identity of the earth-based and space-based seeds is unknown, two data tables will have to be constructed. Draw two tables and label them T seeds and V seeds. Which variable(s) in the Tomatosphere experiment is/are dependent? The health conditions of the space-based seeds, such as percentage of seed germination, rate of germination, health of germination (height, colour, flowers etc.) are the dependent variables. If you plan to make observations according to a regular pattern, such as once a day, once an hour, or once every fifteen minutes, plan to show those times in the data table. Make a draft of your table. Show all the columns and rows you will need and what labels they will have. Insert units into the column labels where they are needed. Write a descriptive title for your table that describes the nature of the experiment and the data being collected. The title must appear at the top of the table with the appropriate table number. 2 Excerpted from Prentice Hall Science Explorer Resources Pro CD-ROM 2000 Pearson Education Inc., publishing as Pearson Prentice Hall. Used by permission. Adapted by: Nandita Bajaj (Northview Heights Secondary School) from Tomatosphere.org Page 6
How frequently are you required to record the data in the Tomatosphere experiment? Show this time in the first column for both types of seeds. once a day For each table, draw additional columns to represent all the dependent variables that will be measured during the experiment. If the variables are quantitative in nature, include units with each column title. Did the seed germinate? (Yes/No) A seed can be considered to have successfully germinated when two (2) distinctly separate cotyledons (embryonic leaves) can be seen. This process will usually take place between 5 and 20 days depending upon local conditions. Height (cm) Colour Did the plant flower? Class Data Table Data for the class will be collected on a daily basis using data collection charts like the ones shown below. Students should rotate throughout the duration of the experiment to collect the data and record it on the class chart. Figure 6: Data collection table for the class for the Tomatosphere experiment Figure 6: Data collection chart for the class for the Tomatosphere experiment Figure 6: Data reporting table for the class for reporting results at the end of the Tomatosphere experiment Adapted by: Nandita Bajaj (Northview Heights Secondary School) from Tomatosphere.org Page 7