Expert: Walter Hintz - 1/15/2007

Question
Hello,
I do not understand the difference between independent variables, dependent variables and control variables in an experiment. My book does not really mention the difference, but my homework asks me to tell which is which in specific examples. Please help!

Answer
 Consider this hypothesis:
A certain fertilizes makes bean plants grow better.
The independent variable is the one that is changed.  there is only one in an experiment. (The amount and kind of fertilizer)
The  dependent variables are the measurements. How tall leaves the plants are or how many leaves)
The controls Everything except fertilizer stays the same. Same amount of water, same type of soil, same amount of flight.