You are given this hypothesis: “if beans are grown in soil with compost, then they will grow at the same rate as beans grown in
soil without compost because compost has no effect on the growth rate of beans.” You have access to these supplies and equipment: fifty bean seeds, fifty small pots, potting soil, compost, and grow lights. Write a brief scientific design to test this hypothesis. Include the aspects of good scientific design described in this lesson.Enter your scientific design in the space below.
You put 1 bean seed in each small pot, fill 25 of the pots with only potting soil, and the remainder with 1/2 potting soil and 1/2 compost. Then you put all of them under an equal amount of grow lights. Put them under at the same time, and take notes every day to see if they grow at the same rate or not. If they do, then it proves this hypothesis is correct. If they don't then the hypothesis is wrong
Divide plants into two groups of twenty-five. Plant twenty-five seeds in pots with potting soil without compost; this is the control group. Plant the other twenty-five in pots with potting soil and a specific amount of compost added; this is the experimental group. Place the pots under grow lights. After germination, measure the height of the plants at set intervals (e.g., every two days) for a set amount of time (e.g., two weeks). The IV is the presence or absence of compost. The DV is the height of plants. Twenty-five plants per group is a good sample size; all obvious variables are controlled. The experiment is simple and specifically described, so it can be replicated. The seeds were assigned randomly; there is no obvious bias in the experiment.
