1st semester science exam- p c m a c（第一学期科学考试- p c m c）.doc

1st Semester Science Exam Study Guide Answers Chapter 1: The World of Physical Science Define the following terms: hypothesis, physics, chemistry, physical science, matter Hypothesis - is an explanation based on research and observations; it must be testable. It is stated in the If …then… because format. Physics – study of energy Chemistry – Study of matter Physical science - is the study of nonliving matter. Its two branches are physics and chemistry. Matter - is the “stuff” everything is made of – all matter has energy because atomic particles are always in motion. All matter has mass. List the steps to the scientific method Make observations, which leads to Ask questions, which leads to Form a hypothesis, which is your best answer to the question Test the hypothesis by conducting an experiment Analyze the results of the experiment including graphing the data Draw conclusions and indicate whether or not the hypothesis should be accepted or rejected. Communicate your results to others List the SI units for measuring: length, mass, and volume Length: meter, mass: kilogram and volume: cubic centimeter (solids and some gases) or liter (liquids and some gases Explain the difference between a scientific law and scientific theory Theories explain what happens and can be used to predict outcomes – theories will change over time as more observations are made. Laws summarize experimental results and observations. Laws tell what happens but not why things happen. Laws are fact and do not change. Why are SI units important? The SI system is easy to use because its units are based on 10, which makes converting to bigger or smaller units much easier. The SI system also uses a standard set of prefixes and provides a common system of measurement throughout the world. Know safety symbols See symbols on page 27 and xxvi in textbook for a review. Explain the difference between a control group and an experimental group An experimental gr