1.5 WS

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Graphs in Science Inquiry Warm-Up, What’s In a Picture? In the Inquiry Warm-Up, you investigated a graph and compared the usefulness of a set of data displayed in writing with the same set of data displayed in a graph. Using what you learned from that activity, answer the questions below.

1. OBSERVE In the graph, which two factors or dimensions are related? What unit is used for each?

2. DESCRIBE Use the information displayed in the graph to rewrite the original written paragraph so that the data about Sarah’s height is described more clearly.

3. COMPARE AND CONTRAST Consider your response to question 2. Why is the data described more clearly in your revision than it was in the original paragraph?

4. INTERPRET DATA Was Sarah’s rate of growth constant from age 1 to age 4? Explain.

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Graphs in Science What Kinds of Data Do Line Graphs Display? 1a.

IDENTIFY The location of a point on a graph is called the (y-axis/x-axis/

coordinate). b. DESCRIBE What is a line of best fit?

c. APPLY CONCEPTS You want to measure how tall your friends grow over one year. What is the independent and dependent variable?

I get it! Now I know that line graphs display data that show ________________________________

I need extra help with _____________________________________________________________

Why Are Line Graphs Powerful Tools? 2a.

REVIEW What does a graph with no trend show about the variables?

b. COMPARE AND CONTRAST How does a graph with no trend differ from a graph with anomalous data points? ____________________________________

I get it! Now I know that line graphs are powerful tools because _____________________________

I need extra help with _____________________________________________________________

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Graphs in Science

On a separate sheet of paper, explain what line graphs show and how they help scientists.

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Graphs in Science Understanding Main Ideas Answer the following questions in the spaces provided. 1. How are line graphs used to show how two variables are related?

2. Why are line graphs powerful tools in science?

Building Vocabulary Fill in the blank to complete each statement. 3. A line graph in which the data points yield a straight line is called a(n) _______________ graph. 4. A graph in which the data points do not fall along a straight line is called a(n) _______________ graph. 5. A(n) _____________ is a “picture” of data.

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Graphs in Science Read the passage and study the graphs below. Then use a separate sheet of paper to answer the questions that follow.

Bar Graphs A bar graph is a good choice to use when the independent variable is not a number and the data displayed is not continuous. Bar Graph A is a graph of this type of data. The independent variable in this case includes three high schools in a county. Because the independent variable is not a number and not continuous, a bar graph is a good choice to display the data. Each of the three schools has a position along the horizontal axis. The dependent variable is the number of students at a high school. The vertical axis is labeled with the dependent variable, and a scale on the vertical axis covers the range of the data collected. In Bar Graph A, each bar shows how many students are enrolled at that school. Bar Graph B shows a variation on the basic bar graph. This graph includes a second independent variable—school year. Each year has different shading, as indicated by the small boxes to the upper left of the graph. Each school now has two bars. This grouping of bars ensures that the reader of the graph understands that the bar graph shows data for two years for each school.

1. 2. 3. 4.

Identify the independent and dependent variables in both graphs. In Bar graph A, how many students attend the largest school? Why are the bars in Bar Graph B shaded differently? Which school had the most students in 2002–2003, and which had the most students in 2003–2004?

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Graphs in Science If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true. 1. _______________ Scientists control changes in the dependent variable. 2. _______________ To help you see what the data from an experiment mean, you could use a(n) graph. 3. _______________ In science, line graphs are powerful tools because they allow you to identify bias, make predictions, and recognize anomalous data. 4. _______________ A graph is a(n) “description” of data. 5. _______________ A point that does not fall exactly on a graph line is a(n) anomalous data point. 6. _______________ Line graphs display data that show how the dependent variable changes in response to the independent variable.

Write the letter of the correct answer on the line at the left. 7. ____ On which of the following graphs do data points yield a straight line? A nonlinear B bar C linear D circle 9. ____ On a nonlinear graph, the data points are never which of the following? A along a curved line B along a straight line C exactly on a graph line D part of a trend

8. ____ When a graph does NOT have any clear trends, it probably means that the variables are which of the following? A dependent B independent C related D not related 10. ____ A line graph is used when which of the following is true? A an independent variable is continuous. B an independent variable is not continuous. C a dependent variable is not continuous. D no variable is continuous.

Graphs in Science Answer Key

1. age and height; years and centimeters (cm), respectively 2. Answers will vary. Sample: At age 1, Sarah was 75 cm tall. At age 2, Sarah was 85 cm tall. At age 3, Sarah was 95 cm tall. At age 4, Sarah was 100 cm tall. 3. Answers will vary. Sample: in my revised paragraph, Sarah’s exact height at each age is given. The original paragraph gives a mix of heights at some ages and differences in height between some ages, so the description of the data is inconsistent. 4. no; Sarah’s rate of growth was constant from age 1 to age 3, when she grew 10 cm each year. But the rate was different between age 3 and age 4, when Sarah grew just 5 cm.

Line graphs show how one variable (the dependent variable) changes in response to another variable (the independent variable). They help scientists identify trends, make predictions, and recognize anomalous data.

1. Line graphs are used to display data to show how one variable (the dependent variable) changes in response to another variable (the independent variable). 2. They allow you to identify trends, make predictions, and recognize anomalous data. 3. linear 4. nonlinear 5. graph

1. Graph A: The independent variable is high schools, the dependent variable is the number of students. Graph B: The independent variables are high schools and school years, the dependent variable is the number of students. 2. 375 3. The bars are shaded differently to show the difference in the school years. 4. South had the most in 2002–2003, while Northwestern had the most in 2003–2004.

1. independent 3. trends 5. true 7. C

9. B

2. true 4. picture 6. true

8. D 10. A