• What is a theory?
    • A theory provides a general explanation for observations made over time.
    • A theory explains and predicts behavior.
    • A theory can never be established beyond all doubt.
    • A theory may be modified.
    • Theories seldom have to be thrown out completely if thoroughly tested but sometimes a theory may be widely accepted for a long time and later disproved.

(Dorin, Demmin & Gabel, 1990)

  • What is a model?
    • A model is a mental picture that helps us understand something we cannot see or experience directly.

(Dorin, Demmin & Gabel, 1990)