How Scientists How Scientists WorkWork

The scientific methodThe scientific method

Designing an experimentDesigning an experiment• Purpose Purpose • ResearchResearch• Form a Hypothesis Form a Hypothesis • ExperimentExperiment• AnalyzeAnalyze• ConclusionConclusion

PurposePurpose• What do you want to know?What do you want to know?

•What question are you trying What question are you trying to answer?to answer?

ResearchResearch• Learn as much as you can about the Learn as much as you can about the

topictopic

HypothesisHypothesis• Make a prediction, state what you Make a prediction, state what you

think will happenthink will happen

• Answer your question.Answer your question.

Controlled ExperimentControlled Experiment• Design a test to either confirm or disprove Design a test to either confirm or disprove

your hypothesis.your hypothesis.• Test your hypothesis by an experiment Test your hypothesis by an experiment

where only one variable is changed at a where only one variable is changed at a time. All other variables should be kept time. All other variables should be kept unchanged/controlled.unchanged/controlled.

• Dependent/responding variableDependent/responding variable= the = the variable that is observed or is being variable that is observed or is being measured.measured.

• Independent/manipulated variableIndependent/manipulated variable= the = the variable that is purposely changed.variable that is purposely changed.

Control GroupControl Group• The group that is left alone, the The group that is left alone, the

group is not being tested for group is not being tested for anythinganything

• used to compare the experimental used to compare the experimental group to.group to.

AnalysisAnalysis• Record your results of the Record your results of the

experimentexperiment

ConclusionConclusion• State whether your hypothesis was State whether your hypothesis was

right or wrong and state why.right or wrong and state why.• Analyze your data and determine Analyze your data and determine

whether your hypothesis was correct whether your hypothesis was correct or incorrect.or incorrect.

How a Theory DevelopsHow a Theory Develops• When we gather and build up enough When we gather and build up enough

evidence to support a hypothesis we call evidence to support a hypothesis we call that a theorythat a theory

• TheoryTheory is a well tested explanation that is a well tested explanation that unifies a broad range of observations.unifies a broad range of observations.

• Theories allow scientist to make accurate Theories allow scientist to make accurate predictions about different situationspredictions about different situations