Although science history includes accounts of serendipitous scientific discoveries, most development of scientific concepts and technological innovation occurs in response to a specific problem or conflict. Both great advances and gradual knowledge-building in science and technology have profound effects on society. Students should appreciate the scientific thought and effort of the individuals who contributed to these advances. For example, from Mendel's story, to the work of Watson and Crick, to modern breakthroughs in gene manipulation for therapeutic purposes, history illustrates every important facet of the nature of science. They will understand that knowledge generated by one generation usually is expanded, modified, or even discarded by the next generation.
Theories just become stronger as more supporting evidence is gathered.
They provide a context for further research and give us a basis for prediction. For example, the theory of biological evolution is an explanation for phenomena such as diversity of species. Gene theory is an explanation for relationships we observe between one generation and the next. Laws are fundamentally different from theories. They are universal generalizations based on observations of the natural world, such as the nature of gravity, the relationship of forces and motion and the nature of planetary movement.