The links at left lead to additional resources to help you with this chapter. These include Hot Links to Web sites related to the topics in this chapter, the Take It to the Net activities referred to in your textbook, and a Self-Test you can use to test your knowledge of this chapter.
Section 1-1: What Is Science?
The goal of science is to investigate and understand nature, to explain events in nature, and to use those explanations to make useful predictions.
Section 1-2: How Scientists Work
Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All the other variables should be kept unchanged, or controlled.
In science, the word theory applies to a well-tested explanation that unifies a broad range of observations.
Section 1-3: Studying Life
Living things share characteristics including cellular organization, reproduction, a universal genetic code, growth and development, use of materials and energy, response to their environment, and maintaining an internal stability.
Living organisms can be studied at different levels of organization, from the molecular level to the biosphere.
Section 1-4: Tools and Procedures
Most scientists use the metric system when collecting data and doing experiments.
Light microscopes produce images by focusing visible light rays. Electron microscopes produce images by focusing beams of electrons.