As you come in, please:
• Get out a sheet of paper and put your name on it.
• Write a definition, from your own memory, for these terms: hypothesis, scientific law, scientific theory, scientific model.
• On the back of the page, draw a picture of scientists doing science. Show some detail: who is working, what they are doing, what they are using.
The Nature of Science
• Science is:
• based on observations and inferences about the natural world.
• a creative human endeavor
• socially embedded.
The Nature of Science
• Science produces:
• Laws
• Theories
• Models
• knowledge that is always tentative (subject to change).
Hypotheses
• A hypothesis
• is a statement that predicts the outcome of an experiment.
• is valid if it is testable, falsifiable, and specific — not if is correct!
• is tested (not “proven”) by scientific inquiry.
Scientific Laws• A scientific law is a description of a
natural phenomenon.
• Laws are based on empirical evidence.
• Examples:
• Mendel’s laws of inheritance.
• The Hardy-Weinberg Law of population genetics.
• Laws may change with new knowledge.
Scientific Theories• A scientific theory is an
explanation of a natural phenomenon.
• Theories are based on empirical evidence.
• Examples:
• The theory of natural selection.
• Cell theory.
• Theories may change with new knowledge
Scientific Inquiry
• The process that creates scientific knowledge is scientific inquiry.
• Inquiry can be:
• Descriptive
• Correlational
• Experimental
Descriptive Studies
• Descriptive studies describe the object of study in detail.
• Characteristic of young sciences.
• Some sciences, such as Astronomy and Taxonomy, rely almost entirely on descriptive studies.
Correlational Studies• Correlational studies describe two
events that occur at the same time, and look for a relationship between the two.
• Many health studies are correlational: they use large databases of health information, and try to answer questions when an experiment would be unethical.
• However, a correlation does not prove a cause.