Learning Objectives Learn the definitions of science, chemistry, and technology. Know the principles of green chemistry. Science is a practice of learning about the natural world. Natural sciences include physics , chemistry , biology , geology and astronomy . Science uses mathematics and logic , which are sometimes called "formal sciences". Natural science makes observations and experiments. Science produces accurate facts , scientific laws and theories. 'Science' also refers to the large amount of knowledge that has been found using this process. People who study and research science are scientists. Scientists study things by looking at them very carefully, by measuring, and by doing experiments and tests. Scientists try to explain why things act the way that they do, and predict what will happen. Chemistry is the scientific discipline that involves the properties and behavior of matter, and the changes matter undergoes during a reaction with other substances. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science , because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level (Figure 1.1.1). For example, chemistry explains aspects of plant chemistry (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties of the soil on the moon (astrophysics), how medications work (pharmacology), and how to collect DNA evidence at a crime scene (forensics). Science is human understanding of how the universe and the things in it work. On the other hand, technology is the use of resources to solve a problem (such as knowledge, skills, processes, techniques, tools, and raw materials). Paleolithic technology is the oldest known, but people likely used technology long before then. The Paleolithic age began when hominids (early humans) started to use stones as tools for bashing, cutting, and scraping. The age ended when humans began to make small, fine tools (Mesolithic); it came to a close when they started to plant crops and develop other methods of agriculture (Neolithic). Technology was once quite simple. It was passed on through word of mouth, until written word was invented. Writing allowed technology to develop much quicker. In the present day, people continue to understand more about the world and the universe. The use of the telescope by Galileo, Einstein's theory of relativity, lasers, and computing are all scientific discoveries. Technology is of great importance to science, medicine, and everyday life. Green chemistry (also called sustainable chemistry ) is a type of chemical research and engineering. It supports the design of products and processes that use the smallest amount of dangerous substances possible. In 1990, the Pollution Prevention Act was passed in the United States. This law sought new and original ways to handle pollution. The Pollution Prevention Act aims to avoid problems before they happen. Green chemistry applies organic chemistry, inorganic chemistry, biochemistry, analytical chemistry, and even physical chemistry. While green chemistry seems to focus on just industrial applications, it does apply to other scientific disciplines. Green chemists aim to reduce the hazards and increase the efficiency of any chemical choice. Green chemistry is distinct from environmental chemistry, which focuses on chemical phenomena in the environment. The 12 Principles of Green Chemistry Prevent waste. Create products without waste, or with minimal wastes, so that the wastes do not need to be taken care of afterwards. Design safer chemicals and products. Design chemicals to have little or no toxicity, without altering effectiveness. Design less hazardous chemical syntheses. Design a way of synthesizing products, without them being toxic to humans or the environment. Use renewable raw materials. Use renewable raw materials, like plant materials; rather than depleting materials, such as fossil fuels. Use catalysts, not stoichiometric reagents. Use catalysts, because of their ability to be able to be reused. Catalysts are less harmful than reagents. Avoid chemical derivatives. Chemical derivatives generate wastes that can be avoided. Maximize atom economy. Maximize the percentage of reactant atoms that convert to usable product atoms in a chemical reaction, so as to minimize or eliminate atomic waste. Use safer solvents and reaction conditions. Avoid using harsh solvents; if that cannot be avoided, then use benign chemicals. Increase energy efficiency. Use the normal ambient temperature and pressure wherever possible. Design for degradation. Design materials to break down into benign substances, by bacterial or other environmentally sound ways. Analyze in real time to prevent pollution. Monitor and control the formation of by-products during a reaction. Minimize the potential for accidents. Design chemicals to minimize the potential for accidents. Summary Science is the human method to make discoveries about the natural world. Chemistry is the branch of science involved with the properties and behavior of matter, and the changes it undergoes during a reaction with other substances. Green chemistry applies organic chemistry, inorganic chemistry, biochemistry, analytical chemistry, and physical chemistry to reduce and prevent pollution. There are 12 guiding principles in the practice of green chemistry.