Scientific MethodScientific Method

Chapter 1Chapter 1

How Scientists WorkHow Scientists Work

How Scientists Work:How Scientists Work: Solving the ProblemsSolving the Problems

Much of biology deals with solving Much of biology deals with solving problemsproblems

These problems can be environmental, These problems can be environmental, ecological, health related, etc.ecological, health related, etc.

No matter what types of problemsNo matter what types of problemsare being studied, scientists use are being studied, scientists use the same problem-solving steps the same problem-solving steps called…called…

The The Scientific MethodScientific Method

Scientific MethodScientific Method Definition Definition The The scientific methodscientific method is- is-

A logical and systematic approach or A logical and systematic approach or process to problem solving.  process to problem solving. 

An organized way of using evidence An organized way of using evidence to learn about the natural world. to learn about the natural world.

Scientific MethodScientific Method Listing the StepsListing the Steps Make an Make an ObservationObservation DefineDefine the Problemthe Problem State the State the HypothesisHypothesis Design an Experiment Design an Experiment to test to test

HypothesisHypothesis Collect and Record Collect and Record DataData AnalyzeAnalyze DataData Draw Draw ConclusionsConclusions Report Report ResultsResults

If needed, Do more investigation

1. Make Observations1. Make Observations

An An observationobservation is is recording a recording a description of description of something unusual something unusual in your natural in your natural world by using world by using your sensesyour senses

As we all know, frogs have four limbs.

What’s up with thesefroggies?

2. Questioning2. Questioning Recognize, state or define the problemRecognize, state or define the problem Ask scholarly questions:Ask scholarly questions:

What…? What…? When…?When…? Where…?Where…? Who…?Who…? Why…?Why…? How…?How…?

3. Researching3. Researching Gather information related to the problem Gather information related to the problem

by:by: Reading, observing , measuring, taking Reading, observing , measuring, taking

samples, etc.samples, etc. How frogs normally develop from eggsHow frogs normally develop from eggs The % of frogs with the The % of frogs with the

deformitiesdeformities Number of other species in Number of other species in

the pond with deformitiesthe pond with deformities Previous or new pollutantsPrevious or new pollutants

in the pondin the pond Change in amount of UV Change in amount of UV

(sunlight) exposure on eggs (sunlight) exposure on eggs

4. Hypothesizing 4. Hypothesizing

A A hypothesishypothesis is:is: An educated guess, trial answer, possible An educated guess, trial answer, possible

solution, solution, predictionprediction Must written as an “If…Then…” Must written as an “If…Then…” statementstatement Must be Must be testable testable or or measurablemeasurable Is based on your research Is based on your research

and previous experienceand previous experience

5. Experimenting5. Experimenting

An experiment is a procedure to test your An experiment is a procedure to test your hypothesis hypothesis

Design an experiment that will realistically Design an experiment that will realistically examine the claim made in the hypothesisexamine the claim made in the hypothesis

Control and Experimental Control and Experimental GroupsGroups

used as a standard of used as a standard of comparison comparison

the group containing the group containing the factor (variable) that has been changedthe factor (variable) that has been changed

Uncovered jars

Covered jars

Two groups of jars

Control groupControl group::

Experimental groupExperimental group::

(manipulated or independent variable)(manipulated or independent variable)

Variables in an Variables in an ExperimentExperiment VariablesVariables - - Factors that can be changedFactors that can be changed Controlled Variables Controlled Variables - - all the variables that remain all the variables that remain

constant constant Manipulated Variable or Independent VariableManipulated Variable or Independent Variable - -

factor in an experiment that a scientist purposely factor in an experiment that a scientist purposely changeschanges or makes different or makes different

Responding VariableResponding Variable or or Dependent VariableDependent Variable - the - the outcome or results, factor in an experiment that may outcome or results, factor in an experiment that may change because of the manipulated variable….change because of the manipulated variable….what a scientist wants to observe or measurewhat a scientist wants to observe or measure

6. Collect and Record Data6. Collect and Record Data

Types of Recorded DataTypes of Recorded Data

QuantitativeQuantitative - - observations that are observations that are numericalnumerical Ex: amounts, frequency, measurements Ex: amounts, frequency, measurements

QualitativeQualitative - - observations thatobservations thatare of a descriptive natureare of a descriptive nature Ex: color, smell, texture, taste, sound Ex: color, smell, texture, taste, sound

Information in the form of observations and measurementsmade in an experiment

Data:Data:

DataData

Data must be grouped neatly and Data must be grouped neatly and organized into: organized into: tables tables charts charts FiguresFigures graphsgraphs

A Table has rows and columns to organize data.

Number of Plants in each area

Plant #

AreaA

AreaB

Area C

AreaD

1 10 6 25 30

2 1 5 3 10

7. Analyze the Data7. Analyze the Data

Examine data tables, charts, and Examine data tables, charts, and graphsgraphs

Examine experimental notesExamine experimental notes Look for Look for trendstrends, , patternspatterns, and , and averagesaverages Report what your data showsReport what your data shows

8. Draw Conclusions8. Draw Conclusions A A conclusionconclusion is a restatement of the is a restatement of the

hypothesis:hypothesis:Ex: The data from the experiment Ex: The data from the experiment

either supports or rejects the either supports or rejects the hypothesis.hypothesis.

Support your conclusion with specific, Support your conclusion with specific, numerical data gathered from the numerical data gathered from the experimentexperiment

9. Determine Limitations9. Determine Limitations

Scientists look for possible flaws in their Scientists look for possible flaws in their researchresearch

They look for faulty (inaccurate) dataThey look for faulty (inaccurate) data They look for experimental error or bias's They look for experimental error or bias's They decide on the validity of their resultsThey decide on the validity of their results They make suggestions for improvement or They make suggestions for improvement or

raise new questionsraise new questions

10. Publish Results 10. Publish Results Communication is an Communication is an

essential part of scienceessential part of science Scientists report their Scientists report their

results in journals, results in journals, on the internet, or on the internet, or at conferencesat conferences

This allows their This allows their experiments to be experiments to be evaluated and repeatedevaluated and repeated

Scientists can build on previous Scientists can build on previous work of other scientistswork of other scientistsRedi’s experiment

on insects generation

Scientific TheoryScientific Theory A A theorytheory is an is an

explanation of a set of explanation of a set of related observations related observations or events based upon or events based upon proven hypotheses proven hypotheses and verified multiple and verified multiple times by detached times by detached groups of researchers groups of researchers

Scientific LawScientific Law Scientific laws Scientific laws represent represent

the cornerstonethe cornerstoneof scientific discoveryof scientific discovery

They must be simple, They must be simple, true, universal, and true, universal, and absolute absolute

If a law ever did not If a law ever did not apply, then all apply, then all science based science based upon that law would upon that law would collapse collapse

Scientific Method