Independent Variable (IV)‣what you change in the experiment‣this “change” needs to be measurable‣examples‣weight‣mass‣volume‣height
Dependent Variable (DV)‣the result from the change you made‣what you measure‣known as data‣“depends” on your independentvariable‣also should be measurable
The IV and DV …‣are close relatives and can be foundthroughout the following steps of thescientific process:‣ASK A QUESTION‣FORM A HYPOTHESIS‣TEST THE HYPOTHESIS‣ANALYZE THE RESULTS/DATA
Ask a QuestionDoes the _________________________affect the________________________?(Dep.Var. - DV)(Ind.Var. -IV)
Form a Hypothesis‣Hypothesis‣a measurable and educated guess‣predicts how the independent variablewill affect the dependent variable
Form a HypothesisIf the _____________ is _____________,(Ind.Var. - IV)(incr./decr.)then the ____________ will ___________.(Dep. Var. - DV)(incr./decr./stay the same)
Test the Hypothesis‣Data Table‣an organized way to record data
Test the HypothesisData TableIndependentVariable – IVDependent Variable - DVTrial One Trial Two Trial ThreeAverage(Mean)
Analyze the Results‣Results‣patterns and relationships betweenwhat you are changing (IV) and yourdata (DV)
Analyze the Results‣Types of Results‣quantitative: numbers, amounts,measurements, etc.‣raw data‣qualitative: comparisons, relationships, etc.‣examples‣bigger/smaller‣thicker/thinner‣brighter/more dull
Analyze the Results‣Line Graph‣represents patterns and relationshipsbetween what you are changing (IV) andyour data (DV)
Analyze the ResultsLine Graph TitleThe effect of the .(Independent Variable – IV)on the .(Dependent Variable - DV)
DependentVariable - DVAnalyze the ResultsLine Graph Set-up …(…title goes here – across the top)Independent Variable - IV
Analyze the Results‣Writing your results‣State the data‣Concentrate on the averages‣Quantitative – numbers‣means, minimum, maximum, range, etc.‣Qualitative – compare the results‣use words like “faster”, “larger”, “less”,“greater”, etc.
Draw Conclusions‣Conclusion‣restate the hypothesis‣decide if your hypothesis was supported‣restate the data‣discuss possible sources of error(SOE’s)‣discuss future applications
Draw Conclusions‣Sources of Error (SOE’s)‣possible changes in materials that couldalter the results of the experiment‣often a result of having too many variables‣all materials other than the independentvariable should remain constant
Draw Conclusions‣Constants‣all factors in an experiment that are keptthe same‣an experiment should only test ONE factor– your independent variable
Draw ConclusionsWriting a Conclusion‣Begin with “My hypothesis stated “If the …”‣Next, “The data did/did not support myhypothesis.”‣Then, explain what the data shows.‣Discuss possible SOE’s and how you couldimprove your experiment (and avoid these SOE’s)next time.‣Compare to the control.
Draw Conclusions‣Control‣the normal expectation of what is tohappen‣what you compare your results to‣example: If you wanted to see if fertilizer wouldincrease a plant’s growth rate you would haveseveral different plants receiving differentamounts of fertilizer, but your control would justreceive water, and no fertilizer.
CommunicateResults‣Write a lab report‣Publish an article in a scientificjournal‣Write a book
You must see theINDEPENDENT VARIABLEand theDEPENDENT VARIABLE‣ASK a QUESTIONwhen you …‣FORM a HYPOTHESIS‣TEST the HYPOTHESIS‣in the DATA TABLES, and‣ANALYZE the RESULTS/DATA‣ in the LINE GRAPH