2 Standards Investigation & Experimentation 1a) Select and use appropriate tools and technology (such as computer-linked probes, spreadsheets, and graphing calculators) to perform tests, collect data, analyze relationships, and display data.1b) Identify and communicate sources of unavoidable experimental error.1c) Identify possible reasons for inconsistent results, such as sources of error or uncontrolled conditions.1d) Formulate explanations by using logic and evidence.1f) Distinguish between hypothesis and theory as scientific terms.1k) Recognize the cumulative nature of scientific evidence
3 What is Science?Science is method of thinking about the natural world.Biology is the scientific study of life.
4 Scientific MethodThe scientific method is a problem-solving procedure scientists use to seek answers to questions.
5 THE SCIENTIFIC METHOD PROBLEM HYPOTHESIS EXPERIMENT FORM A NEW HYPOTHESISREPEAT THE WORKRECORD DATA &ANALYZE RESULTSCONCLUSIONACCEPT HYPOTHESISREJECT HYPOTHESIS
6 Scientific Method 1. Identify a Problem 2. Create a Hypothesis 3. Design and perform an experiment.4. Record Data and Analyze5. State a Conclusion6. Repeat the Work
7 1. Identify a ProblemObservations are descriptions about the way something is or the way things happenFrom these observations, a question is formed about why or how
8 Example: Identify a problem Barney observes:When I drink Coke, I burp a lot.He asks Professor Frink:Why does Coke cause burping?
9 Example: Identify a problem Professor Frink explains:You can do background research to help you know moreLook online about the physiology of burping
10 Wikipedia - not always 100% accurate, but a good start for background information carbon dioxide in drinks causes gas pressure to build in the stomach
11 2. Create a HypothesisA Hypothesis is a prediction that may provide an answer to the questionMust be testableShould be written in the form of an“If…, then…” statement
12 Example: Create a Hypothesis If people drink Coke,then they will burp more.
13 3. Controlled Experiment Test the hypothesisProcedure—the steps followed during an experimentWell designed experiments have experimental group(s) & a control group
14 Example: ExperimentProfessor Frink wants to determine if Coke will increase the frequency of burping.He gives 10 volunteers (subjects) from Springfield Coke and another 10 subjects water. All other conditions are kept the same.All people are years oldAll people are healthy.All people have to not eat or drink for 3 hours before the experiment.
16 Control Group: all variables are kept the same (constant) Used as “normal” for comparisonExperimental Group: all the same variables except the one thing you are testingVariables: anything that can influence the outcome of the experiment
17 Example: Experiment Control Group: people who drink water only Experimental Group: people who drink CokeVariables: age of subjects, health of subjects, having food or drinks before the experiment
18 Independent Variable: What you are testing The variable that is changedDependent Variable: what is measured or observedThe variable that changes because of the independent variable
19 Independent Variable: type of beverage Dependent Variable average number of burpsIndependent VariableControl
20 The experimental group gets the independent variable-Coke. The control group gets the control-water.Independent VariableControl
21 4. Record Data & Analyze Collect & record Data (information) Qualitative data: descriptionsQuantitative data: numbersData can be recorded in a tableAnalyze the data by graphing itBar graphs: show comparisonsLine graphs: show changes over time
22 Example: Recording Data Average # of BurpsControl Group: Water2Experimental Group: Coke6Dependent Variable: what you measureIndependent VariableControl
23 Analyze the Results: Bar Graph Proper unitsTitleAverage Number of Burps for Water vs. CokeY-axis = Dependent VariableType of BeverageX-axis = Independent VariableLabel
24 5. ConclusionsThe results tell whether the hypothesis was “accepted or rejected”
25 Example: Conclusion Accept or reject the hypothesis? Why? ACCEPT! There were more burps with Coke than with water based on the data and the results of the graph.
26 6. Repeat the WorkWhen a hypothesis is supported by data from additional investigations, it is considered valid.When a hypothesis is not supported, it means that we need to go back and ask new questions or identify sources of error in the experiment.
27 Sources of error: things that may effect the results of the experiment Sample Size: more subjects means more accurate resultsControl all other variables but the one you are testingLength of experiment (hour vs. a day?)Amount of variable (2 cokes vs. 1?)Type of material (coke vs. pepsi?)Other: light, temperature, age, health, male vs. female, etc.
28 Hypothesis vs. TheoryHypothesis: an educated guess that may or may not be trueTheory: a well-tested explanation that unifies a broad range of observationsIn science, theories are nearly factsEx. Theory of Evolution,Theory of Relativity,Cell Theory
29 THE SCIENTIFIC METHOD FORM A NEW HYPOTHESIS REPEAT THE WORK ACCEPT HYPOTHESISREJECT HYPOTHESIS
30 THE SCIENTIFIC METHOD PROBLEM HYPOTHESIS EXPERIMENT FORM A NEW HYPOTHESISREPEAT THE WORKRECORD DATA &ANALYZE RESULTSCONCLUSIONACCEPT HYPOTHESISREJECT HYPOTHESIS