Objective

Farming in a Simulated Martian Environment

Objective (March 2015)

To compare the germination rate of tomato seeds and the vigour of the growth of tomato plants, after seed exposure to the following environmental conditions:

Exposure to conditions in the Earth's environment only. (the control group)
Sand the other is the "treatment" group, which was subjected to a simulated space environment

Your Tomato Seeds
	Tomato seeds are relatively small, about 2 - 3 mm in length. They are light enough to be blown away in drafts from open doors and windows. Seeds should probably be kept in their sealed envelopes until just prior to planting. In this investigation you will be working with seeds from two different sources. It is very important that you do not get them mixed up. All seeds should be germinated simultaneously under identical conditions in order to control as many variables as possible.
Acquire the Planting Medium
	Decide how and where you will germinate the tomato seeds. Peat pellets are strongly recommended. They will expand significantly when they absorb water, as shown in the photograph. Compare the fully expanded pellet on the left with its original compressed form on the right. They can be set out in the bottom of the container, their own miniature greenhouse. Covering the container with clear plastic wrap reduces evaporation. Simply add water, plant the seeds, and cover them with the transparent plastic roof.
Develop a Plan (Space, Time and Procedure)
	Space: You will be evaluating and measuring the germination properties of approximately 60 seeds, (Two sets of 30, each set having a different environmental history). 60 peat pellets will be placed in two germination greenhouses in the growlab on the counter, all seeds are germinated under identical conditions. You will need labelled containers for 60 peat pellets. You are using two trays, containing 30 pellets each. Time: Plan to have four (4), more or less, uninterrupted weeks in which to perform this experiment so that (except for weekends) observations can be taken, and recorded, daily. It is also best to set up a schedule to identify students, and times to make observations. Teachers have recommended that you plant on a Wednesday or Thursday in order to see the first germination the following week. Procedure: Due to the important nature of this experiment it is essential that you develop a plan to keep track of which seeds are which. Develop a method to accurately identify each group of seeds.
Prepare Your Germination Centre
	Label all containers clearly and indelibly prior to planting. In this way seed groups can be quickly identified. Set up the germination centre before you actually plant any seeds. The conditions of temperature, light, and humidity must remain uniform for all of the seeds during the experiment. Decide where you will place the germinating seeds so that they will not be disturbed, and where uniform germinating conditions will exist. Germinating seeds do not require sunlight. They do however, require moisture, a moderate temperature (not too warm), and oxygen. Do not place your seeds in direct sunlight (they may become overheated). A broad window sill where the temperature is about 20^oC throughout the day is ideal. If there is any chance that your seed trays will be exposed to direct sunlight, a provision to give them full shade should be implemented. Our tray placement is: ______________________________
Plant The Seeds
	The first step is to soak the peat pellets for about 20 minutes in water at room temperature (or until they are fully saturated with water). HINT: To minimize the chances of accidentally mixing up seed groups, plant only one seed group at a time into their appropriately labelled containers, although it is important to plant all seeds on the same day. As has been pointed out, tomato seeds are very small. Each seed should be pressed gently into the depression in the centre of the peat pellet, to a depth of about 2-3 mm, approximately the length of the tomato seed itself. Plant only one seed per pellet. Place the pellet in its labelled container.
Observe and Record
	Detailed and carefully recorded observations are essential to completing a successful experiment. Observations should be recorded daily. Use copies of the Data Sheet which are provided. Monitor the germination conditions. 1. Seeds must be kept moist, but not wet. Water gently using a fine spray from above, or by adding a small amount of water in the peat tray to keep the peat pellets uniformly moist. 2. Germinating seeds prefer a moderately warm uniform temperature. Large changes in temperature inhibit seed germination. 3. Ensure that all seeds are germinated under identical conditions. 4. Avoid direct sunlight.

Assuring Objectivity
	The two sets are labelled "A" and "B". The origin of the seeds will be revealed following the completion of the experiment and your submission of the results. You will need to record the number of seeds planted and the number of seeds germinated. This is called a "blind" study; it is designed to eliminate unintentional bias in the experimental process.
Biased Observations
	It is well known that sometimes our expectations determine the outcome of an experiment, such as experimenting with the taste of new foods. Presented with a big, fat, roasted grub (considered a fine delicacy in some societies), we generally expect that it will taste awful ... and if we conjure up enough bravery to try it, it usually does taste awful upon taking the first bite, even though it may taste exactly like peanuts or cashews ... our expectations prejudice our observations. Similarly, in a scientific investigation, it is possible to influence our observations by unconsciously tampering with the experimental controls or biasing our observations. For example, moving a specific group of tomato seeds to a warmer location after the experiment has begun because we expect or hope that this specific group of seeds will germinate better is a case of tampering with the experimental controls.

If we record a dead, partially germinated, seed as "unsuccessfully germinated" in one group while recording such a seed in a similar state as having been successfully germinated in a different group (because we were fairly certain the second group should be more successful). This would be an example of inaccurate or biased reporting .

Biased observations are usually made unconsciously by the observer and are rarely deliberate attempts to misrepresent the data.

For this reason blind studies are used whenever possible for many scientific studies, including the Tomatosphere Project