Chapter 1: Introduction to Science

1.1 The Nature of Science1.2 The Way Science Works1.3 Organizing Data

Vocabulary

• Scientific Notation• Precision• Significant figures• Accuracy

Line Graphs

• Line Graphs: best for showing data that changes• x-axis: independent variable (bottom of

graph)• y-axis: dependent variable (side of graph)

Bar Graphs

• Bar Graphs: useful for comparing data for several individual items• Makes large or

small differences in data very clear

Pie Chart

• Pie Chart: useful for displaying data that are parts of a whole

• Add up to 1 or 100%

Parts of a Graph

• Title of Graph• Label axis/pie chart• UNITS!• All data• Zero (on line and bar graphs)• Set up EQUAL divisions

Analyzing Data from Graphs

• Outliers: data that is abnormally high or low• Unusual or rare data

• Mean: the average (add up all data points and divide by total number of data points)

Analyzing Data from Graphs

• Median: number in the middle when data is displayed from least to greatest

• Mode: the data that shows up the most often

Significant Figures (aka “sig figs”)

• Rules for Sig Figs:1. Non-zero digits are ALWAYS significant

2. Any zeros between sig figs ARE significant

3. A final zero or trailing zero in the decimal portion ONLY are significant

Sig Fig Examples

• How many sig figs are in each number?• 3.0800• 0.00418• 7.09 x 10-5

• 91,600• 0.003005• 3.200 x 109

• 250• 780,000,000• 0.0101• 0.00800

Significant Figures in calculations:

• When you +, -, ×, or ÷, your answer should only be as precise as the least precise measurement in the calculation

Sig Figs

• Example: A gummy bear has the dimensions of 1.34 cm long, 0.82 cm wide, and 1.0 cm high. Find the volume of the gummy bear with the correct # of sig figs. (Remember: V = l × w × h)

Scientific Notation

• Why? So scientists can easily express numbers that are very large or very small.

• What? A simple number (1 or greater AND less than 10) multiplied by a power of 10

• Examples: • 6.24 × 106

• 2.1 × 10-2

Scientific Notation

• How?1. Using original number, move decimal so

that the number is one or greater and less than 10.

2. Count how many places the decimal was moved.

Scientific Notation

• If the number you started with is greater than 1, the exponent is POSITIVE

• If the number you started with is less than 1, the exponent is NEGATIVE

• Scientific notation can be reversed to write the number in standard form again.

Accuracy vs. Precision

• Accuracy: how close a measurement is to the true value

• Precision: how exact a measurement is