Section 1: The Method of Science

Science is a process that uses observation and investigation to gain knowledge about events in nature.  It’s based on logic and evidence with the goal of providing explanations and understanding patterns about how and why things happen.  Scientists then use the information or knowledge gained to make predictions about future occurrences.  Science covers three main categories: life science, earth science, and physical science.

When scientists pose a question or design an experiment, they follow an organized set of investigative procedures called the scientific method.  The scientific method has distinct steps.  First, an observation is made that leads to a question about how or why something occurs.  After asking a question, a hypothesis, or educated guess, or testable prediction, is made.  Next, an experiment is conducted that includes an organized and detailed procedure for testing the hypothesis.  When conducting an experiment, a control, or standard for comparison, is needed.  If there are too many variables changed in an experiment, then researchers aren’t able to discern which variable is responsible for any results they may get.  A constant is a factor that doesn’t vary in an experiment.  The independent variable is a factor that is adjusted by the experimenter and it’s found on the x-axis when graphing the data.  The dependent variable is a factor with a value that depends on the independent variable, and it’s found on the y-axis.  Finally, the data collected is analyzed and conclusions are drawn.

Evidence from research leads scientists to propose scientific theories or explanations based on experiments.  A scientific theory is a logical explanation that is based on data and not a guess.  For example, when you are playing the game Clue, you might say, “I have a theory that Colonel Mustard killed Mrs. Peacock in the study with the wrench.”  But when a scientist talks about a theory, like the black hole theory, they are referring to a well-tested explanation based on observations, research, and data.  A scientific law is a rule of nature that sums up the related observations to describe a pattern in nature, and it is true all the time.  The law of gravity is a scientific law.


  1. What is a hypothesis?
  2. On what axis is the independent variable plotted?
  3. Explain the difference between a scientific theory and scientific law?

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