Using Percent of Change to Measure NC Growth

Students will work in small groups to use the Internet to gather data on the population growth for each of the 100 counties in NC from 1992 to 1995. From this data students will find the percent of increase/decrease for the counties they have been assigned. As a follow-up, the students will enter their data into a computer spreadsheet and from that spreadsheet, produce graphs of the information.

A lesson plan for grade 8 Mathematics and Social Studies

By Wanda Washburn

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Related topics

• Learn more about mathematics and social studies.

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Learning outcomes

Students will:

• calculate the percent of increase/decrease from given data.
• search the Internet for the populations of the NC counties during the years 1992 and 1995 in teams of two or three.
• enter their information into a spreadsheet and use that spreadsheet to print out a graph of the counties and their populations.

Teacher planning

Time required for lesson

1.00 weeks

Materials/resources

• 8th grade pre-algebra textbook
• Teaching transparencies/overhead projector
• Projector pens
• Paper/pencils
• Computer paper
• A large blank map of NC that shows the counties. This can be drawn using an opaque projector.

Technology resources

• Computer with Microsoft Works or another program with spreadsheet capabilities.
• Access to the Internet.
• Printer - a color printer would be preferred for producing the graphs.

Pre-activities

If necessary, review percents. Students must be able to rewrite decimals as percents.

If necessary, review some basic and familiar formulas showing students how to substitute values. Students must be able to use formulas to find percent of change.

In a discussion of North Carolina, talk about NC today and the present population. Include student ideas about where they feel that most North Carolinians live within the state. What are the large cities? Why do students feel that these areas have the greater populations? With students, find on the Internet the present population of the state as well as the population at various time periods. See if students can use their knowledge of US and NC history to justify the growth and movement of population. Populations for the counties can be found at http://statelibrary.dcr.state.nc.us/iss/NC_Data/pop_estimates.html.

Activities

Day 1:

Using the 8th grade textbook, teach the math concept of percent of change. Show the students the following steps to find the percent of change. For example to find the percent of change from 120 to 135:

1. Divide the new amount by the original amount.

   135 divided by 120 = 1.125

2. Subtract 1 from the result and write the decimal as a percent.

   1.125 - 1 = 0.125 or 12.5%

The percent of change is 12.5% increase.

Repeat the procedure for data that decreases. Help students to know that the negative number that results from subtracting 1 in the first step indicates a percent of decrease. Also, they should expect a decrease, if the end amount is less than the original amount.

If necessary, work several other examples on the overhead. Many texts include examples on overhead transparencies that can be used.

Assign students problems for classwork/homework from their texts.

Day 2

1. Check the classwork/homework from the previous class.
2. Using populations relating to North Carolina that you found with students in the pre-activities, find some percents of increase and decrease. For example: cities that were prominent in Colonial times that are now less well known, how much your own town has grown, growth of well known cities such as Raleigh, Charlotte, Asheville, etc.
3. Assign students partners with which to work. Give each pair ten counties to research for population in 1992 and 1999. The counties can easiest be assigned alphabetically, but using counties grouped together in geographic areas will enable the teacher and students to see from the graphs how the population compares throughout the state. Provide students with the math lab handout (see attachment) to be used in research. Together the students will find the information and make the spreadsheet and the graph. The students should individually complete the percent of change from 1992 to 1999 for each county.

Days 3 and 4

1. Using a large blank map of the outline North Carolina (if not available any large NC map will work), place the bar graphs the students have made in the regions where their counties are located.
2. Discuss the populations observed. Where are the most people? Which areas are showing the most growth? Does anyone have any ideas about why these areas are more populated? Since the students have used the same program and instructions to prepare their graphs, the answers to these questions should be very visible to the students.

Assessment

Students will receive 25 points for the spreadsheet, 25 points for the graph, and 5 points each for the correct percent of change for each county.

Supplemental information

None

Related websites

NC State Library
http://statelibrary.dcr.state.nc.us

NC Population Statistics
http://statelibrary.dcr.state.nc.us/iss/NC_Data/pop_estimates.html

Comments

Having students continue to learn about the counties that were assigned to them could extend this lesson. More research could be done using the Internet as well as other reference material. Students could write to the counties for more information about topics such as tourist spots, institutions of higher education, industry, or historic places in the county.