6Key Terms:Control Group: group that doesn’t receive experimental treatment; used for comparisonVariable:Independent: conditions you choose/manipulateExperimental: the one independent variable that you are testingDependent: what you measure; data you collect
7Key Terms:Sample Size: number of subjects that you run your experiment onSampling Error: error that arises from testing too few subjects (too low a sample size)
8Example experiment: You want to determine what the optimal amount of water is for plants. You set up 4 identical corn plants and give them each different amounts of water over two weeks.Plant 1: no waterPlant 2: ½ literPlant 3: 1 literPlant 4: 1.5 literCollect data, draw a conclusion
9Which plant is the control? What is the sample size?What is the dependent variable?What are some independent variables?What is the experimental variable?Is the experimental variable an independent or dependent variable?
10What is the difference between your data and your conclusion?? Think about this when identifying the dependent variable. It is your DATA not your conclusion!!
11Scientific Method You notice something (Observation) It makes you wonder, why? Or How? (Ask a Question/State your Problem)You think about it for a while. Based on the knowledge you have, you think you have an idea, but aren’t sure(Form a Hypothesis)You decide to test out your idea (Experiment)New HypothesisYou look at the results of your tests.(Data analysis)Does it look like your hypothesis was right?Or do your results suggest something else?Support of HypothesisAfter many repetitions of the tests by you and other “observers”, all of which continue to support your hypothesis,Hypothesis becomes aTheory