Christopher G. Hamaker, Illinois State University, Normal IL © 2008, Prentice Hall

Chemistry: The Central Science Most other sciences demand an understanding of basic chemical principles, and chemistry is often referred to as the “central science.” Chapter 1

Evolution of Chemistry The Greeks believed in four basic elements: earth, air, fire, and water. All substances were combinations of these four basic elements. Chapter 1

Scientific Investigations Science is the methodical exploration of nature followed by a logical explanation of the observations. Scientific investigation entails: planning an investigation carefully recording observations gathering data analyzing the results Chapter 1

The Scientific Method The scientific method is a systematic investigation of nature and requires proposing an explanation for the results of an experiment in the form of a general principle. The initial, tentative proposal of a scientific principle is called a hypothesis. After further investigation, the original hypothesis may be rejected, revised, or elevated to the status of a scientific principle. Chapter 1

Applying the Scientific Method Step 1: Perform a planned experiment, make observations, and record data. Step 2: Analyze the data and propose a tentative hypothesis to explain the experimental observations. Step 3: Conduct additional experiments to test the hypothesis. If the evidence supports the initial proposal, the hypothesis may become a theory. Chapter 1

Scientific Method, continued After sufficient evidence, a hypothesis becomes a scientific theory. A natural law is a measurable relationship. Chapter 1

Critical Thinking: Reactions with Oxygen What do burning wood, rusting iron, and exploding gasoline have in common? All three are examples of combustion. Combustion is a chemical reaction of a substance with oxygen. Rusting is slow reaction, burning is rapid reaction, and an explosion is instantaneous reaction. Chapter 1

Modern Chemistry Chemistry is a science that studies the composition of matter and its properties. Chemistry is divided into several branches: Organic chemistry is the study of substances containing carbon. Inorganic chemistry is the study of all other substances that don’t contain carbon. Biochemistry is the study of substances derived from plants and animals. Chapter 1

Learning Chemistry Different people learn chemistry differently. What do you see in the picture? Some people see a vase on a dark background; some people see two faces. Chapter 1

Problem Solving Connect the dots using only four straight lines. Experiment until you find a solution. Did you have to use 5 straight lines? No matter which dot we start with, we still need 5 lines. Chapter 1

Problem Solving Are we confining the problem? We need to go beyond the 9 dots to answer the problem. Chapter 1

Chemistry, The Central Science Knowledge of chemistry is important to understanding the world around us. Chapter 1

Chapter Summary Scientists use the scientific method to investigate the world around them. Experiments lead to a hypothesis, which may lead to a scientific theory or a natural law. Chemistry is a central science with many branches. The impact of chemistry is felt in many aspects of our daily lives. Chapter 1