The order of steps in a scientific method can vary. Most scientific methods to solving a problem, however, include defining the problem, stating a hypothesis, testing the hypothesis, analyzing the results of the test, and drawing conclusions.

• Variables are factors that change in an experiment. A dependent variable can change in response to changes in the independent variable. A control is a standard for comparison.

• Basic units used in SI include the liter, the meter, the second, the kilogram, the Newton, and degrees Celsius.

• In scientific notation, a number is expressed as a multiplier and a power of 10.

Methods of Scientists 1.2