The Scientific MethodThe Scientific Method

A Way to Solve a ProblemA Way to Solve a Problem

Mrs. MacWilliams

The The ““StepsSteps”” of the of the Scientific MethodScientific Method

AAnna nna

FFound ound

TTwenty wenty

AAdorable dorable

DDogs and ogs and

CCatsats

Step 1Step 1

AAnna = nna = AAsk a Questionsk a Question Scientists Scientists observeobserve the world around them, the world around them,

identify problems, and develop identify problems, and develop questionsquestions..

Ex. Do violent video games give kids high Ex. Do violent video games give kids high blood pressure?blood pressure?

Step 2Step 2

FFound = ound = FForm a orm a HYPOTHESISHYPOTHESIS HypothesisHypothesis: A TESTABLE explanation for : A TESTABLE explanation for

observations and data. observations and data.

* I like to call it “An answer to your question”* I like to call it “An answer to your question” A good hypothesis is stated in such a way that it A good hypothesis is stated in such a way that it

is clear what should be tested and measured.is clear what should be tested and measured.

Ex. Playing violent video games DOES NOT Ex. Playing violent video games DOES NOT increase kids blood pressure.increase kids blood pressure.

Step 3Step 3

TTwenty = wenty = TTest the hypothesisest the hypothesis The next step scientists take is to The next step scientists take is to create a create a

procedure to conduct an experimentprocedure to conduct an experiment to test to test their hypothesis.their hypothesis.

With your partner, think of ways you could test With your partner, think of ways you could test the game/blood pressure hypothesis.the game/blood pressure hypothesis.

Variables and GroupsVariables and Groups Independent Variable-Independent Variable- thing that you thing that you manipulatemanipulate in an in an

experiment. (What you are TESTING)experiment. (What you are TESTING) Ex. Playing Video GamesEx. Playing Video Games

Dependent Variable-Dependent Variable- the the responseresponse to the independent to the independent variable (What you are MEASURING)variable (What you are MEASURING)

Ex. Blood Pressure changingEx. Blood Pressure changing

Experimental group-Experimental group- person/thing that person/thing that receivesreceives the the drug/treatment/devicedrug/treatment/device

Ex. The people playing VIOLENT video gamesEx. The people playing VIOLENT video games

Control group-Control group- person/thing used as the person/thing used as the comparisoncomparison (DOES NOT receive the drug/treatment/device)(DOES NOT receive the drug/treatment/device)

Ex. The people playing NON-VIOLENT video gamesEx. The people playing NON-VIOLENT video games

PLACEBO!PLACEBO!

An An inactiveinactive substance which may look like substance which may look like medicine but contains no medicine. In medicine but contains no medicine. In some studies, the participants in a control some studies, the participants in a control group may be given a placebo.group may be given a placebo. Ex. People given a Ex. People given a ““sugar pillsugar pill”” and told it is a and told it is a

blood pressure medicationblood pressure medication

Step 4Step 4

AAdorable = dorable = AAnalyze Datanalyze Data A key to experimenting is observing what A key to experimenting is observing what

happens and writing it down.happens and writing it down. Scientists analyze data by creating charts, Scientists analyze data by creating charts,

graphs, or other VISUAL forms to question graphs, or other VISUAL forms to question and discuss.and discuss.

Ex. The blood pressure readings varied at Ex. The blood pressure readings varied at different times.different times.

Step 5Step 5 DDogs = ogs = DDraw conclusionsraw conclusions

Scientists draw conclusions about data and Scientists draw conclusions about data and determine if it agrees with the hypothesisdetermine if it agrees with the hypothesis

When drawing conclusions STATE WHETHER When drawing conclusions STATE WHETHER THE HYPOTHESIS IS SUPPORTED OR THE HYPOTHESIS IS SUPPORTED OR REJECTED!REJECTED!

Ex. Blood pressure readings increased each time Ex. Blood pressure readings increased each time the kids played violent video games but not when the kids played violent video games but not when playing non-violent video games. There fore, the playing non-violent video games. There fore, the violent video games caused their high blood violent video games caused their high blood pressure. HYPOTHESIS IS REJECTED.pressure. HYPOTHESIS IS REJECTED.

Step 6Step 6

CCats = ats = CCommunicate Resultsommunicate Results Scientists share their experiments and Scientists share their experiments and

findings with othersfindings with others• Because they share their experiments and Because they share their experiments and

findings, scientists can learn from each other and findings, scientists can learn from each other and often use someone elseoften use someone else’’s experiences to help s experiences to help them with what they are studying or doing.them with what they are studying or doing.

Scientific TerminologyScientific Terminology SCIENTIFIC THEORYSCIENTIFIC THEORY: summarizes a observations and : summarizes a observations and

hypotheses that enables scientists to hypotheses that enables scientists to attempt an explanation attempt an explanation of what was observedof what was observed Example: the Big Bang Theory postulates that the universe Example: the Big Bang Theory postulates that the universe

began almost 14 billion years ago with a massive began almost 14 billion years ago with a massive expansion eventexpansion event

SCIENTIFIC LAWSCIENTIFIC LAW: summarizes observations, but : summarizes observations, but does not does not explain themexplain them. A law may be in the form of a mathematical . A law may be in the form of a mathematical formula. It describes a relationship that never changes.formula. It describes a relationship that never changes. Example: E = mcExample: E = mc22

SCIENTIFIC PRINCIPLESCIENTIFIC PRINCIPLE: a concept based on scientific laws : a concept based on scientific laws and rules that are agreed upon by the scientific community. and rules that are agreed upon by the scientific community. Principles are subject to change if conditions change.Principles are subject to change if conditions change. States of matter: solid, liquid, and gasStates of matter: solid, liquid, and gas

Scientists make observations. Scientists will then formulate a hypothesis based on inferences in order to explain their observations. Once the hypothesis is tested and confirmed, it becomes a theory. Only when a theory has withstood every challenge and has been proven to provide reproducible results does it become a recognized scientific law or scientific principle. There is no 'proof' or absolute 'truth' in science. The closest we get are facts.