3 Observation vs. Inference Observation: can be made with only the five senses (sight, touch, hear, taste, and smell)Observations not guesses, assumptions or opinion.Inference: logical assumption based off of prior knowledge or after very limited observation
8 Observation or Inference? There are 9 tentacles.
9 HypothesisEducated prediction made from various observations- It is NOT guess!Useful only if it can be tested.If I do this (manipulated variable), then I think this will happen (responding variable) because………
10 The Experiment: experimental design Setting up an experimentControl group (generally what is “normal”)Controlled variablesExperimental groupVariables:Manipulated variable (independent variable)Responding variable (dependent variable)
11 Why only have one manipulated variable per experiment?
12 Data collection Large sample size Use of a data table Variables easy to identifyMeasurable resultsOutliers can cause data distortionHow can you recognize outliers?Multiple trials give most accurate results
13 After an experiment is complete: Results, more testing, new hypotheses, more experiments, more results…and on and onwork is usually publishedPeer review process- Experiments must be successfully repeated by other scientistsAfter many years, after many scientists, lots of supporting evidence, new theories are acceptedAtomic TheoryCell theoryGerm Theory
14 Theory vs Law Law Theory Explains one topic No longer adding evidence to lawsTheoryExplains a multiple hypothesesUnifies evidence from multiple studiesContinually adding evidence to theories