1-2 How Science Works Copyright Pearson Prentice Hall

I. Scientific Hypothesis Scientific Hypothesis A scientific hypothesis is a tentative explanation of an observation or pattern which has been observed in nature. Copyright Pearson Prentice Hall

Designing an Experiment How do scientists test hypotheses? A hypothesis should be tested by an experiment in which only one variable is changed at a time. Copyright Pearson Prentice Hall

Designing an Experiment The process of testing a hypothesis includes: Asking a question Forming a hypothesis Setting up a controlled experiment Recording and analyzing results Drawing a conclusion Copyright Pearson Prentice Hall

How a Theory Develops As evidence from numerous investigations builds up, a hypothesis may become so well supported that scientists consider it a theory. In science, the word theory applies to a well-tested explanation that unifies a broad range of observations. Copyright Pearson Prentice Hall

II. Scientific Theory Scientific Theory A scientific theory is an explanation of a natural phenomenon with a broad range of significance and application. Copyright Pearson Prentice Hall

III. Scientific Law Scientific Law A scientific law is an empirical (ie based on experimental evidence) statement of great generality of something which seems to always be true. Copyright Pearson Prentice Hall

IV. Differences between Hypothesis-Theory-Law Scientific law is a generalization. It is NOT an explanation. It is the result of induction. It is an empirical (ie based on observation alone) statement of something which always appears to be true. Hypotheses and theories, on the other hand, are an attempt to explain what has been observed. Often scientists form theories to explain laws. Copyright Pearson Prentice Hall