PARAMETERS, VARIABLES AND THE SCIENTIFIC METHOD

Variable is a factor that can change or be measured in an experiment. The word variable is used interchangeably with the word parameter.

There are different types of variables or parameters. Controlled variables are kept constant during the experiment. Manipulated Variable is the variable the scientist intentionally changes. Responding variable is the variable that is measured and changes because of the manipulated variable.

EX: A scientist wants to determine if fertilizer has an effect on leaf size of a plant. The manipulated variable is ___________ The responding variable is ____________

There is another set of terms used to describe variables: Independent Variable is the same as manipulated variable. It is the one the scientist changes. Dependent Variable is the same as responding variable. It is the one the scientist measures as a result of changing the manipulated variable.

Read page 12, designing an experiment and fill in the following: In order to really analyze your results, you need a controlled experiment. In a controlled experiment only one variable or parameter is changing and all the others are controlled or held constant. Read page 12, designing an experiment and fill in the following: Manipulated variable ______ Responding Variable _____ Controlled Variable(s) _____ Dependent Variable _______ Independent Variable ______

GRAPHING VARIABLES: Manipulated or Independent Variable always on X axis. Responding or Dependent Variable always on Y axis. (see page 13)

Examples of Variables Question Ind. Variable/Man. Var. Dep. Variable./Resp. Var. Cont. var. Does heating a cup of water allow it to dissolve more sugar? How much water flows through a faucet at different openings? Is a classroom noisier when the teacher leaves the room?

An experiment was designed to determine if the taste of coffee was affected by the amount of coffee grounds used. Ind. Var. _________________ Dep. Var. _________________ C. Var. __________________ C. Var. __________________