scientific method. steps in the scientific method (sm) observation observation hypothesis hypothesis...

Scientific MethodScientific Method

StepsSteps in the in the Scientific Scientific Method (SM)Method (SM)

ObservationObservation HypothesisHypothesis ExperimentExperiment Data CollectionData Collection ConclusionConclusion PublishPublish RetestRetest

ObservationsObservations

Gathered Gathered through through using using your your sensessenses

A scientist A scientist notices notices

something something occuring in occuring in

their their natural natural worldworld

ObservationsObservations

An An exampleexample of of an observationan observation

might be might be noticing that noticing that

many deer are many deer are dying by being dying by being

hit by cars hit by cars driving toodriving too

Fast. Fast.

HypothesisHypothesis

A A suggested suggested solutionsolution to the to the problem.problem.

Must be Must be testabletestable

(Super important)(Super important) Sometimes written Sometimes written

as as If…Then…If…Then… statementsstatements

PredictsPredicts an outcome an outcome

HypothesisHypothesis

An An example of a example of a hypothesishypothesis might be that might be that more deer will more deer will live if the speed live if the speed limit was limit was lowered. lowered.

ExperimentExperiment

A A procedure procedure that that teststests

the the hypothesis.hypothesis.

ExperimentExperiment

VariableVariable – – factorfactor in the in the experiment experiment that is being that is being

testedtested

ExperimentExperiment

A goodA good or or “valid” “valid”

experiment experiment will only will only

have have ONE ONE variable variable

being tested!being tested!

Controls and VariablesControls and Variables

Scientific Scientific Experiments Experiments Follow RulesFollow Rules

An experimenter changes one factor and observes or measures what happens.

The The Control VariableControl Variable The experimenter makes a The experimenter makes a

special effort to special effort to keep 1 keep 1 factor the same or factor the same or unchangedunchanged so that they so that they will not effect the outcome.will not effect the outcome.

Those factors are called Those factors are called control variables.control variables.

What is the Purpose of What is the Purpose of a Control?a Control?

Controls are NOT being tested

Controls are used for COMPARISON

Other Variables The factor that is changed

is known as the independent variable.

The factor that is measured or observed is called the dependent variable.

You Are Already You Are Already Scientists!Scientists!

For example, suppose you want to figure out the fastest route to walk home from school.

You will try several different routes and time how long it takes you to get home by each one.

Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.

What are the Variables What are the Variables in Your Experiment?in Your Experiment?

Different routes are the Different routes are the independent variable.independent variable.(changing) (changing)

The time it takes is the The time it takes is the dependent dependent variablevariable (being measured) (being measured)

Keeping the same walker Keeping the same walker (yourself) throughout makes the (yourself) throughout makes the walker a walker a control variable.control variable.(used for (used for comparison) comparison)

One more thing… it is best to make several trials with each independent variable. The more data…the better.

Valid ExperimentsValid Experiments

Mr. G example

Lochsa River Madness

Class example

Remember: To be a Remember: To be a Valid (Good) Valid (Good) Experiment:Experiment:

Two groups are required --- the control & experimental groups

There should be only one variable being tested.

DataData Is Results

(recordings) of the experiment

May be quantitative (numbers) or qualitative

DataData Must be

organized Can be

organized into charts, tables, or graphs

ConclusionConclusion

The answer to the hypothesis based on the data obtained from the experiment

Publish and RetestPublish and Retest

In order to verify the results,

experiments must be retested.

Publish in peer Publish in peer reviewed journal.reviewed journal.

Peer reviewed means that once your study is done, many other scientists with knowledge of your study go through how your experiment

was performed. If they find ANYTHING wrong or untrue, the experiment is not published.

Basically, a peer reviewed published study is very trustworthy.

Problems with studies that aren’t peer reviewed?

Hidden motives?

Solving a ProblemSolving a Problem1)Identify a Problem2) State Observations

about the problem3) Form a Hypothesis

about the problem (if…then…)

4) Design an Experiment to test the hypothesis

5) Collect Data6) Form a Conclusion7) Retest