Designing an experimentFirst state the problem.( Asking a question)

Collect information.

Formulate a hypothesis which will drive your experiment.

Test Hypothesis-Design an experiment.

What is an experiment?An experiment is a procedure designed to

test a hypothesis.

The results of an experiment will either support a hypothesis or cause it to be rejected.

Designing an ExperimentWhen designing an experiment, you must

consider variables.

Variables are any factor that can affect the results of an experiment.

All experiments have two types of variables.

Types of VariablesIndependent /Manipulated variables- are

manipulated or controlled by the experiment.

Dependent/ Responding variables- respond to changes in the independent variables.

The dependent variable is the variable being measured in the experiment.

Practice:Hypothesis: A plant grown in a larger pot will

grow taller than one grown in a smaller pot.

What is the independent/manipulated variable?

What is the dependent /responding variable ?

Independent and Dependent Variables

Question IndependentVariable

DependentVariables

How does salt affect water’s freezing point?

Which fertilizer grows the largest apples?

What size parachute slows a free fall faster?

Types of groups used when designing an experiment

A reliable experiment includes both a control and experimental group.

Types of GroupsControl group- represents the norm and shows

what would happen when the independent variable is not manipulated or controlled.( the group that is not affected)

Experimental group- has conditions identical to those of the control group except for the variable being studied.( the group that is being tested)

Types of Groups ……To test a hypothesis fairly, only one

independent variable in an experiment should be changed at a time.

If more than one variable changes, it will not be clear which variable affected the dependent variable.