Section 2 Methods of Scientists

Essential Questions What are independent and dependent variables? How does experimentation and investigation differ? What are the differences between mass and weight? What is scientific notation and how is it used?

Review Vocabulary experiment: procedure performed in a controlled setting to test a hypothesis and collect precise data

New Vocabulary scientific methods control hypothesis Le Système International d’Unités (SI) independent variable dependent variable scientific notation

The Nature of Scientific Investigations A hypothesis is a testable explanation of a situation that can be supported or disproved by careful procedures. It is important to note that scientific methods are not rigid, step-by-step outlines to solve problems. Scientists can take many different approaches to performing a scientific investigation. David Wasserman/Stockbyte/Getty Images

Measurement

Scientific Notation In many branches of science, some commonly used numbers are very small, while others are very large. To express these numbers conveniently, scientists use a type of shorthand called scientific notation, in which a number is expressed as a value between 1 and 10 multiplied by a power of 10. The power of 10 is the number of places the decimal point must be shifted so that only a single digit remains to the left of the decimal point. (t)Fotosearch RF/Glow Images, (inset)David Scharf/Science Source

Assessment 1. Which type of scientist is shown at the right? oceanographer A geologist B CORRECT astronomer C USGS meteorologist D

Assessment 2. Which type of research is this scientist conducting? field research A CORRECT lab research B library research C USGS biological research D

Assessment 3. Which is a sequence of steps a scientist might use to conduct an investigation? analysis, test, question, conclude A test, question, conclude, analysis B question, test, analysis, conclude C CORRECT conclude, test, question, analysis D

Assessment 4. Select the correct scientific notation for 150,000,000 km. 150 × 106 km A 15 × 107 km B 1.5 × 108 km C CORRECT 0.15 × 109 km D