The word “science” comes from the Latin word “scientia” which means “knowledge”. Science covers the broad field of knowledge that deals with facts and relationships among these facts. Scientists study a wide variety of subjects. Some scientists search for clues to the origin of the universe and examine the structure of the cells of plants and animals. Other researchers investigate why we act the way we do or try to solve complicated mathematical problems. Scientists use systematic methods of study to make observations and collect facts. They develop theories that help them order and unify facts. Scientific theories consist of general principles or laws that attempt to explain how and why something happens or has happened. A theory becomes a part of scientific knowledge if it has been tested experimentally and proved to be true. Scientific study can be divided into three major groups: natural, social, and technical sciences. As scientific knowledge has grown and become more complicated, many new fields of science have appeared. At the same time, the boundaries between scientific fields have become less clear. Numerous areas of science overlap and it is often hard to tell where one science ends and other begins. All sciences are closely interconnected. Science has great influence on our lives. It provides the basis of modern technology — the tools and machines that make our life and work easier. The discoveries and inventions made by scientists also help shape our view about ourselves and our place in the universe. Technology means the use of people’s inventions and discoveries to satisfy their needs. Since people appeared on the earth, they had to get food, clothes, and shelter. Through the ages, people invented tools, machines, and materials to make work easier. Nowadays, when people speak of technology, they generally mean industrial technology. Industrial technology began to develop about 200 years ago with the invention of the steam engine, the growth of factories, and the mass production of goods. It influenced different aspects of people’s lives. The development of the car influenced the way people lived and worked. Radio and television changed their leisure time. The telephone revolutionized communication. Science has contributed much to modern technology. Science attempts to explain how and why things happen. Technology makes things happen. But not all technology is based on science. For example, people had made different objects from iron for centuries before they learnt the structure of the metal. But some modern technologies, such as nuclear power production and space travel, depend heavily on science.