Chemistry and Scientific Methods Fall 2009 Chemistry and Scientific Methods

What is Chemistry? The branch of science that deals with the properties of substances and the reactions that transform them into other substances. AKA – the study of matter and the changes it undergoes Chemistry is a central science. Chemistry uses the scientific method to advance its knowledge.

What is Matter? Matter is anything that has mass and takes up space. Mass is a measurement that reflects the amount of matter in a sample of a substance. Weight is a measure not only of the amount of matter, but also the effect of Earth’s gravitational pull on that matter. Volume is a measurement of the amount of space taken up by the sample of matter.

Chemistry Chemistry As a Central Science Atmospheric Sciences Physics Oceanography Medicine Economics Governments Chemistry People Geology Biology Politics Astronomy Anthropology

Branches of Chemistry – Table 1-1 p.9 Area of Emphasis Examples Organic Chemistry Most carbon-containing chemicals Pharmaceuticals, plastics Inorganic Chemistry In general, matter that does not contain carbon Minerals, metals and nonmetals, semi-conductors Physical Chemistry The behavior and changes of matter and the related energy changes Reaction rates, reaction mechanisms Analytical Chemistry Components and composition of substances Food nutrients, quality control Biochemistry Matter and processes of living organisms Metabolism, fermentation

The Scientific Method It is an orderly and systematic approach to answering questions about the worls. Information or data is gathered by careful observation of the phenomenon being studied. On the basis of that information a preliminary generalization or hypothesis is formed. A series of experiments is devised to test the predictive power of the hypothesis.

The Scientific Method (cont.) On the basis of the experimental tests, the hypothesis may be (a) Accepted as scientific theory. (b) Modified so that all results are adequately explained. (c) Discarded.

Components of the Scientific Method Making Observations Formulating Hypothesis Extracting Predictions From the Hypothesis Performing Experiments Drawing Conclusions Communicating Results

Experimental Variables A variable is any factor in the experiment that can change. Independent variable – the variable that the researcher plans to change Dependent variable – the variable that you are measuring to see if it was effected by the change in the independent variable Constants – factors that you keep the same among all trials so that they do not effect the results

What is a control? A control is a standard for comparison. It helps the researcher to know what would happen under “normal” conditions.

Definitions Law – a summary of observed behaviors. (It describes but does not explain.) Ex. Law of Gravitation or Newton’s 3 Laws of Motion Hypothesis – a possible explanation of an observation or set of observations. Theory – A set of tested hypothesis that gives an overall explanation of some natural phenomenon or phenomena. Ex. Atomic Theory or Einstein’s Theory of Relativity

Remember: The #1 job of a scientist is to rule out hypotheses. "The great tragedy of Science - the slaying of a beautiful hypothesis by an ugly fact." - T.H. Huxley

Scientific Research Pure research seeks to gain knowledge for the sake of knowledge. (Just curious about what would happen if…) Applied research is undertaken to solve a specific problem. (How can we prevent to hole in the ozone from getting bigger?) Technology is the practical use of scientific knowledge. (cell phones, electric cars, etc.)

Textbook Assignment Review the Chapter Summary for Sections 1.2-1.4 on p.21. Look a the vocabulary words on p.22. Add any terms and definitions not covered in your notes to the bottom of your notes. On a separate sheet of loose-leaf paper to turn in write the questions and answers for p.22 (27-34).