In: Biology
How many variables should an experiment have?
The things, which are changing in an experiment are known as variables. A variable is any factor, trait and condition, which exists in varying amounts and types.
An experiment has three kinds of variables: independent, dependent, and controlled.
The independent variable is changed by the scientist. To insure a fair test, a good experiment has only one independent variable. As the scientist changes the independent variable, it observes what happens.
The dependent variables are the things that the scientist focuses its observations on to see how they react to the change made to the independent variable. If there is a direct connection between the two types of variables (independent and dependent) then uncovers a cause and effect relationship. The number of dependent variables in an experiment varies, but there can be more than one.
Experiments also have controlled variables. Controlled variables are quantities that a scientist wants to remain constant, and she must observe them as carefully as the dependent variables.