You and your hypothetical lab partner each develop anexperimental plan to test this hypothesis. The two experimentalplans are presented below. Evaluate each plan for its pros and consin the experimental design using the bullet points below. Bothexperimental plans have some good elements and areas that could beimproved.
Experiment A) Mature 2 inch sections (sprigs) of Elodeawill be used to measure oxygen production under different lightconditions. 5 sprigs will be tested. One will be kept in the dark(no light). The others will be exposed to a light filtered withcellophane. One sprig’s light will be filtered through clearcellophane to receive all wavelengths of light, and the othersprigs’ light will be filtered through red, blue, and greencellophane, respectively. The no-light plant will be kept in a darkcabinet, while the other plants will be together on a counter. Eachplant sprig will be placed in equal sized upside-down test tubes in100ml of tap water so that oxygen bubbles produced by the plantwill be trapped at the top of the test tube. A ruler will be usedto measure the length of the oxygen pocket collected at the top ofthe test tube. The experiment will continue until one sprigproduces 5 cm of oxygen in the tube.
Experiment B) 3 cm sections (sprigs) of Elodea ofvarious ages will be used to measure oxygen production underdifferent light conditions. 15 sprigs will be divided into 3 groupsof 5 sprigs each. One group will receive natural sunlight, onegroup will be exposed to a blue light bulb under a box to blocknatural light, and the final group will be exposed to a red lightbulb under a similar box to block natural light. Each group ofplant sprigs will be trapped under a clear plastic funnel that iscovered by an upside-down test tube to collect oxygen bubblesproduced by all the sprigs in the group. All groups will be in100ml of water of the same temperature and pH. The experiment willcontinue for 24 hours, and then the volume of oxygen gas producedwill be measured by multiplying the length of the oxygen pocket bythe circle described by the test tube, ?r2. The averagevolume produced by all groups will be graphed and compared todetermine which condition produced the most total volume ofoxygen.
Consider the following questions to evaluate experimental plansA and B (DO NOT ANSWER THESE QESTIONS)
What is the independent variable suggested by the hypothesis? Doboth plans test the independent variable equally well?
What is the dependent variable in each experiment? Whichexperiment’s dependent variable best matches the prediction in thehypothesis?
What are the experimental and control groups for eachexperiment? Which experiment gives the best opportunity to assessthe effect of the independent variable?
How does each experiment account for standardized variables?Which experiment do you think is the better controlledexperiment?
How is sample size addressed in each experiment? Which would youfind to be more convincing?
Does either experiment describe any statistical analyses to beperformed on the data?
ANSWER THIS QUESTION: BELOW
Considering your analysis of each of the questionsabove,write an improved experimental design to test thehypothesis “If blue light is more effective at promotingphotosynthesis, then more oxygen gas (O2) will beproduced when plants are exposed to blue-filtered light compared toother wavelengths.â€You may use elements of the aboveexperiments
