1. Section 2
Methods of Scientists

2. 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?

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

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

5. 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

6. Measurement

7. 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

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

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

10. 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

11. 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