The New Dictionary of Cultural Literacy, Third Edition. 2002.
Physical Sciences and Mathematics
The physical sciences include physics, chemistry, and astronomy, along with related branches of engineering. They are the most highly developed of the sciences, and serve as a model for development of other areas of learning. Mathematics, while not a science itself, is the language in which the physical sciences are written, and hence has had a close relation with these sciences throughout history.
Physics is the study of matter and motion. It is divided into two sections: classical physics, which is the science as developed before 1900; and modern physics, which encompasses twentieth-century work. Classical physics is further divided into mechanics, the study of motion; thermodynamics, the study of phenomena related to heat; and the study of electricity and magnetism. The content of each of these fields can be summarized in a few basic laws from which all the rest of the contents can be derived by mathematical reasoning. There are three laws for mechanics (Newton’s laws of motion), three for thermodynamics (known simply as the laws of thermodynamics), and four for electricity and magnetism (Maxwell’s equations). If you add to these Newton’s law of universal gravitation (now known to be a special case of general relativity), you have a handful of laws that explain everything that was studied by scientists to the end of the nineteenth century, from the motion of the moon in its orbit to the flow of blood through an artery.
In the twentieth century, two new fields were added to physics: relativity, which deals with objects moving near the speed of light and which constitutes our modern theory of gravitation; and the study of the atom and the particles that compose it. The latter field occupies the bulk of the attention of modern physicists.
The atom consists of a nucleus and electrons circling around the nucleus; the ways in which atoms come together to form molecules is governed by the behavior of the electrons. When the number of atoms in a molecule is in the thousands or hundreds of thousands, the basic laws of atomic behavior discovered by physicists are of limited use, and the complex interactions of the molecules constitute their own field of study. The infinite variety of possible atomic combinations is the domain of chemistry. In the same way, the new science of materials, in which scientists produce substances with new and hitherto undreamed-of properties, involves procedures for arranging atoms in new ways.
The nucleus of the atom is composed of elementary particles, which are themselves composed of things called quarks, which are still more elementary. The study of the interactions of elementary particles at high energy is the frontier of knowledge in physics today.
We now know that stars, like people and trees, have life cycles—that they are born, live out their lives, and die. The sun and other stars are powered by nuclear reactions in their core and die when the nuclear fuel is consumed.
Cosmology is the branch of astronomy concerned with the universe as a whole, as well as its origin. The universe is expanding and is believed to have originated about fourteen billion years ago, in an event known as the Big Bang. The study of these origins is an important frontier in astronomy.
Mathematics does not involve experimentation or observation of nature and is therefore not a science like physics or chemistry. In mathematics, one may start with assumptions and rules of logic and use deduction to reach conclusions. Plane geometry of the type taught in high school is a good example of how this procedure works. Alternately, as in the study of statistics, one may start with a set of incomplete data and use induction to reach conclusions. Mathematicians provide the tools that physical scientists apply to their studies of the world. Modern mathematics has, however, become extremely abstract and is well beyond the reach of the general public (and even of most scientists). Consequently, only those notions of mathematics that are likely to be encountered in general discussion are included in the following list.
