Grammar reference: Passive Voice. Participle II.

Read the text and name the parts.

The world of Physics

1. Physics is the science devoted to the study of matter and energy. Physicists try to understand what matter is and why it behaves the way it does. They seek to learn how energy is produced, how it travels from place to place, and how it can be controlled. Physicists are also interested in how matter and energy are related to each other and how they affect each other over time and through space.

The word physics comes from a Greek word meaning natural things. Solid-state physicists developed the tran­sistor and other semiconductor devices. These devices contributed to the enormous growth of the electronics industry since World War II. Knowledge obtained from the study of physics is important in other sciences, in­cluding astronomy, biology, chemistry, and geology. There is also a close connection between physics and practical developments in engineering, medicine, and technology. For example, engineers design cars and aeroplanes according to certain principles of physics. Laws and theories of physics have enabled engineers and scientists to put satellites into orbit and to receive information from space probes that travel to distant regions of the solar system.

2. Physicists try to answer basic questions about the world, how it is put together, and how it changes. So physicists, called experimental physicists, perform the fully designed experiments and then compare the results with what was predicted to happen. Such predictions come from laws and theories developed by another group of physicists, called theoretical physicists. 

The subjects studied by physicists consist of two broad categories, classical physics and modern physics. These two categories differ primarily in emphasis classical physics deals with questions regarding motion and energy.

It is composed of five basic areas: mechanics, heat, sound, electricity and magnetism, and light. Modern physics concentrates on scientific investigations of the basic structure of the material world. Its fields include atomic, molecular, and electron physics; nuclear physics; particle physics; solid-state physics; and fluid and plasma physics.

Mechanics is the study of bodies at rest and in motion. For example, it describes how force acts upon an object, to produce acceleration. The mechanics of body in motion is sometimes referred to as dynamics. The mechanics of body at rest is called statics. One branch of mechanics, known as fluid mechanics, deals with the behaviour of liquids and gases. 

Heat. The study of heat is called thermodynamics. It involves investigating how heat is produced, how it is transmitted from one place to another, how it changes matter, and how it is stored. Thermodynamics also includes cryogenics, the study of material at very low temperatures. 

Sound. The study of sound is called acoustics. Sound consists of vibrations that are produced by an object travel through a medium, such as air, water and so on. Understanding sound is important for designing auditoriums, hearing aids, tape recorders, record players, and speakers. The study of sound also includes ultrasonics, which deals with vibrations that have frequencies too high for human beings to hear. 

Electricity and magnetism are so closely related that scientists often refer to the two of them together as Electromagnetism.

Light. The study of light is called optics. Optics has two major branches, physical optics and geometrical optics. In physical optics, physicists study the nature of light and the physical processes by which it is emitted (given off) from bodies and transmitted from place to place. Geometrical optics is the study of how light trav­els from place to place, and how the direction of travel is affected by different materials. 

Atomic, molecular, and electron physics are concerned with understanding the structures of molecules and atoms. In particular, they concentrate on the behaviour, arrangement, motion, and energy states of the electrons that orbit atomic nuclei. 

Nuclear physics involves the study of the structure and properties of the atomic nucleus. It focuses on ra­dioactivity, fission, and fusion. 

Particle physics. Physicists have discovered that the protons and neutrons within atomic nuclei are formed of still more elementary particles. Particle physicists conduct research by using devices called particle accel-erators. These devices can raise subatomic particles to very high speeds. 

Solid-state physics, also called condensed-matter physics. Solids may be classified according to how the electrons and nuclei of the different atoms that make them up interact with each other. 

Fluid and plasma physics. The modern physics of fluids is built on the principles of classical fluid mechan­ics. Understanding the behaviour and movement of flu­ids is important for the design and construction of cars, ships, aeroplanes, and rockets, as well as for the study of weather. 

3.With a knowledge of physics, human beings can harness the forces of nature and put them to work. By using the principles of physics, people build generators to produce electricity for homes and factories. They burn gasoline to drive automobile engines, and they lift tons of scrap iron with a magnet.

     Physicists enable us to harness different kinds of energy and put them to work. For example, an understanding of sound energy makes possible the musical instruments that combine to produce great symphonies. Knowledge of how light energy can be controlled enables photographers to take beautiful pictures.

Homemakers come into contact with the laws of physics when they use a vacuum cleaner or an electric iron. At home, we also enjoy phonograph records and television programs – all made possible by an understanding of physics. Every time you pick up the telephone or send a telegram you are putting physics to work.