# Charting Historical Gas Prices

## Subjects

• Educational Technology
• Mathematics
--Algebra
--Applied Math
--Statistics

• 6-8
• 9-12

## Brief Description

Students create a graph to illustrate the historical actual price vs. the inflation-adjusted price of a gallon of gasoline.

## Objectives

Students

• observe and talk about historical data that shows the price of a gallon of gasoline over the years.
• use an online tool to find the inflation-adjusted cost of a gallon of gasoline over the years.
• create a graph to provide a visual representation of the actual cost vs. the inflation-adjusted cost of a gallon of gasoline.
• reflect on what they learned by creating their graphs.

## Keywords

graph, chart, table, gasoline, inflation, actual cost

## Materials Needed

• gasoline cost data (provided)
• computer access (for access to an online inflation calculator; this could be done in a computer lab or as a whole-class activity in the single-computer classroom)
• graph paper

## Lesson Plan

When gas prices are adjusted for inflation, a gallon's actual cost today may be not much more than it was years ago.

For example, back in 1980, a gallon of gas cost about \$1.13.

More recently, in early 2012 a gallon of gas cost an average of \$3.80.

When the rate of inflation is figured in, however, the cost of a gallon of gas in 1980 was actually \$3.12 (in 2012 dollars). So in 2012 gas prices are only about 68 cents higher than they were in 1980.

You can use an online inflation calculator to verify that.

Note: Different inflation calculators might vary in the results they present. The results will depend upon the data that supports them. If you calculate the adjusted-for-inflation value in 2012 of \$1.13 in 1980, results on the calculator above might vary slightly from those presented by calculator 2 or calculator 3.

Introduce to students the data below, which shows the average price of a gallon of gasoline from 1950 to 2005.

 YEAR PRICE PER GALLON 1950 .27 1955 .30 1960 .31 1965 .31 1970 .35 1975 .53 1980 1.13 1985 1.19 1990 1.13 1995 1.14 2000 1.66 2005 2.10

Also see figures from 2006 and later (students will need to select the "show past 6 years" option and then average 4 or 5 data points for each year to come with an annual average price for a gallon of gas).

If you have access to computers or a computer lab, let students use one of the inflation calculators above to calculate the inflation-adjusted cost (value compared to the current value of the dollar) of a gallon of gasoline. Create a chart to show that. Depending on the calculator you use, the results should look something like this:

 YEAR PRICE PER GALLON INFLATION-ADJUSTED PRICE 1950 .27 2.19 1955 .30 2.19 1960 .31 2.05 1965 .31 1.92 1970 .35 1.76 1975 .53 1.92 1980 1.13 2.68 1985 1.19 2.16 1990 1.13 1.69 1995 1.14 1.46 2000 1.66 1.88 2005 2.10 2.10

Now it's time for students to graph their results.

Note: If you teach upper elementary or middle school students, you might collect and plot fewer points of data than if you teach high school students.

Provide students with a sheet of graph paper. You might have set up a sheet for them for this activity, or they might set it up on their own.

• Across the horizontal X axis mark the years at equal intervals. If you are plotting all of the data above you will need to create a graph that marks a point for each year from 1950 to the present. If you teach younger students you might have them plot data for fewer years; for example, for 1972, 1982, 1992, 2002 and 2012.
• Across the vertical Y axis mark the values at equal intervals. For example, if you are plotting all of the data on the table above, your Y values will need to range from \$0.00 to \$4.00.
• Add a challenge by having students plot both the actual price per gallon and the inflation-adjusted price per gallon.

The resulting graphs (which will look something like a less-detailed version of this one) will give student a visual representation of the price of gasoline over the years. They will see from the graph that while the actual price of a gallon of gasoline has increased, the cost of a gasoline adjusted for inflation has not increased as steadily. Bottom line, people today are not necessarily using more of their weekly paycheck to pay for gasoline than they might have used 40 years ago.

## Assessment

Have students write in their journals a brief explanation of what they learned from doing this activity.

## Lesson Plan Source

EducationWorld.com

Gary Hopkins

## National Standards

MATHEMATICS: Number and Operations
NM-NUM.6-8.1 Understand Numbers, Ways of Representing Numbers, Relationships Among Numbers, and Number Systems
NM-NUM.9-12.1 Understand Numbers, Ways of Representing Numbers, Relationships Among Numbers, and Number Systems

MATHEMATICS: Algebra
NM-ALG.6-8.3 Use Mathematical Models to Represent and Understand Quantitative Relationships
NM-ALG.6-8.4Analyze Change in Various Contexts
NM-ALG.9-12.3 Use Mathematical Models to Represent and Understand Quantitative Relationships
NM-ALG.9-12.4 Analyze Change in Various Contexts

MATHEMATICS: Data Analysis and Probability
NM-DATA.6-8.3 Develop and Evaluate Inferences and Predictions That Are Based on Data
NM-DATA.9-12.3 Develop and Evaluate Inferences and Predictions That Are Based on Data

MATHEMATICS: Connections
NM-CONN.PK-12.3 Recognize and Apply Mathematics in Contexts Outside of Mathematics

MATHEMATICS: Representation
NM-REP.PK-12.1 Create and Use Representations to Organize, Record, and Communicate Mathematical Ideas
NM-REP.PK-12.3 Use Representations to Model and Interpret Physical, Social, and Mathematical Phenomena

TECHNOLOGY
NT.K-12.1 Basic Operations and Concepts
NT.K-12.3 Technology Productivity Tools
NT.K-12.5 Technology Research Tools

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