1. Probably they include negatives and, if possible, positive controls. Is your negative control a test plant that is planted in a pot with no legume planted in the pot? Do you have any other negative controls? How about positive controls? Are there some plants which you know will grow well under the conditions that you are specifying? Are you using these as positive controls, while your test plants will be a different type of plant? 2. I suspect they also include a method of checking, periodically, for results “over time,” meaning either daily, weekly, monthly …. 3. Wouldn’t you want all of your test “subjects” exposed to the same environmental conditions, with the exception of the one element for which you are testing.
That means that all get the same amount of light, water and soil and that the light, water and soil are from the same source. So, you will need a way of measuring the amount of light, water and soil. If you are planting in containers, wouldn’t you want all of the containers made of the same substance, instead of having some be of plastic and some of wood? Wouldn’t you want them to all be the same height, width and depth? Wouldn’t you want them all oriented with respect to the sun such that none blocked sunlight from the others? Wouldn’t you want to weed them all frequently and regularly to insure that the presence of weeds did not adversely effect one or the other of your test subjects?
I suspect that your instructor wants you to say in your experimental proposal write up how you will orient the containers and what they will be made of and what are their dimensions and how often you will check for weeds and measure light water and soil… 4. Won’t you need to decide what constitutes a positive result and what constitutes a negative result. 5. Probably your instructor wants you to choose an objective measure for your results and state what that will be.
For example: If you are growing other plants along with the legumes, will you measure the growth of their stems with a ruler? If they are branched, will you only measure the total height, or will you measure all of the branches separately? If they have fruit, will you weight the fruit? If you weigh it, how will you decide that it is time to pick and weigh it? At the end of the experiment, will you remove the whole plant, roots and all and weigh it?
6. Will you plant the legumes at the same time that you plant the test plant? or will you plant the test plant on day 5, 6, 10… after the legumes have been planted? Will you plant only one legume to each box? If you have them growing at the same time, how will you orient your plants so that neither the legume nor the test plant will overshadow the other but that the roots of the legume are close enough to effect the soil for the test plant? Or, if you don’t think that will work, will you plant the legumes and let them grow and die before you plant your test plant?
7. How will you record what you have done? Will you make a spreadsheet and record that, for example, you have gave all the plants a cup of water per day or a quart of water twice a week? Where will you note the growth of the plant? how many weeds you pulled? Will you note the conditions of the leaves of your test plant or the conditions of the legume plants? Where will you note any unforeseen changes? 8. How will you write up your results? Most scientific papers have 5 sections. Does your instructor wish for you to include this in your proposal? 1) Introduction,
2) Materials and Methods
4) Conclusions and Discussion,