Predicting Human Population Change Part 2: Population Predictions
Lesson 6 of 10
Objective: Students will be able to predict future patterns of population growth in different countries based on data they collect about current population and current growth rates.
This is the second lesson in a three lesson sequence (Links to Part One and Part Three) asking students to collect and interpret data to make predictions about population growth in three different countries.
Like the other lessons in this sequence, this lesson requires your students to use computers to collect data from internet databases. While it may be possible for them to do so using smartphones or tablets, I recommend using computers if they're available since some of the online resources have interactive components that just function better on desktops or laptops. We have access to a computer cart in my classroom, but if that is a resource you share with other teachers or you have a more traditional computer lab, you may want to make sure to make arrangements to use those computers ahead of time.
Connection to Standards:
In this lesson, students will follow a complex, multi-step procedure, integrate multiple information resources to address a problem, develop claims supported by evidence, conduct research, and model with mathematics to arrive at a better understanding of cause and effect relationships in complex systems.
There isn't as much warm up necessary as the previous lesson because this is a direct continuation. Still, it's helpful to go over a few terms and concepts from the describing populations lesson that will be necessary to complete the activity.
I ask the following questions to begin the lesson:
- "What, again, is a population?", A: the number of individuals living in a place at one time
- "If two countries have a 1% growth rate and one country has 100 million inhabitants and the other has 10 million inhabitants, will they add the same number of people? Why or why not?", A: No, the bigger country will add more because 1 percent of a hundred million is a million people. The smaller country will only add 100 thousand people.
- "What is population density?", A: the number of inhabitants per unit of area.
- "Why is a country with a high population density more 'crowded' then a country with low population density?", A: because they have more people living in the same space.
This last question may need an example: "Russia has a much larger population than El Salvador, but is much, much less dense. Why?", A: Russia is the largest country in the world by area, El Salvador is comparitively tiny.
Once we have gone over this quick review, I ask students to work with the same partner as the previous lesson and have one partner get and set up one computer for the pair and the other partner pick up the activity instructions, a sheet of graph paper, and a box of colored pencils.
Compared to the interactive website used in the previous lesson, this lesson's website is comparatively easy to use. Still, I like to give a short demonstration so that students are familiar enough with the expectations to get started on the activity as quickly as possible.
- What is the current population?
- What is the 1 year change? I then explain that this is the "Growth Rate"
- What is the area?
- What is the population density?
- What is the fertility rate? (since fertility rate is a term that won't be introduced until the demographic transition lesson, I explain that it is the number of children the average female in the country will have in her lifetime)
I then direct their attention to the table at the top of their activity worksheet and point out that we just found the information for the U.S. I then ask them to write the names of the countries they investigated in the previous lesson in the "Country Name" spaces of the table.
Please Note: If you choose to do this lesson as a standalone lesson and students have not already chosen countries to collect data and predict future population growth, I would suggest that you have them start with the worldometers website and choose 3 countries based on the "1 year change" which is a measure of current growth rate. I would suggest that they choose:
1 country with a high growth rate (greater than 2%) Example: Nigeria, 2.82%
1 country with a moderate growth rate (between 1% and 2%) Example: Mexico, 1.2%
1 country with a low growth rate (less than 1% or negative growth) Example: France, 0.54%
I then ask them to use the worldometers website to find the information for their first country and complete the table.
I walk around the room to check that all students can find their selected country and are recording the data. Once I have seen that all groups can successfully complete this table, I let them know that they will come back to this website to complete the first part of the activity, but that I want to also demonstrate how to project the growth of the populations using this compound interest calculator.
Even though I include the following instructions on the activity worksheet, I demonstrate how to use the website to project population growth using the United State's data:
- Enter the current (2015) population in the “Current Principal” space.
- Leave the “Annual Addition” box blank
- Enter the number of years away from the date for which you are creating your projection (e.g., 10 for 2025, 20 for 2035) in the “Years to Grow” box
- Enter the growth rate in the “Interest Rate” box
- Press “Calculate”
- The “Future Value” box will show your projected population
As simple as these instructions are, this calculator is a bit more complicated for students to work with (possibly because of the large quantities involved). So, I let them know that if they have trouble when they get to this section of the activity to let me know and I can help them on a case by case basis.
Once I have demonstrated how to use both websites, I let students begin the independent practice section to complete the activity.
Once students begin working independently, I move around the room troubleshooting technology and helping them answer the data interpretation questions as needed.
When students begin to make their graph of each country's projected population change, I check to make sure that they are using an appropriate scale, that they have clearly marked units, that they have a key, a title, etc. See the lesson on making a graph for more details on the expectations I have for my students when making graphs.
In some cases, it may be necessary for students to make a separate graph, or an inset graph at different scale, if their selected countries have widely different populations (e.g., it's hard to analyze a graph of India and Guatemala's population on the same graph. The scale will make the Guatemala's growth curve look flat, regardless of the fact that it is actually growing at a fast rate.) If there are such wide variations, there should be plenty of blank space to make an inset graph at a different scale.
A lot of students have trouble with understanding that projected population growth is different than projected population size. Since different groups arrive here at different times, I make sure they can do this with at least one country's data when I see a particular group reach this section. Sometimes, however, students ask me the question first, so it's important to be moving around enough to be available as needed.
Many students also have trouble with calculating projected population densities. Again, since they come to this section at different times, I help students with this when they arrive at that section. The important thing I try to emphasize is that, although the population is projected to change in the future, the area of the country will stay the same, so any population growth means the country will become more dense.
Some student groups' countries may actually have a negative growth rate and be projected to shrink. In these cases, I make sure to check that students understand that these countries are projected to become less dense in the future.
See the reflection for a specific example of student work and the issues that came up for them based on their countries of choice.
Like the previous lesson, I use the last 20-30 minutes checking on students interpretations of the data they’ve collected. For the final question about population density, I encourage students to consult maps of their countries to see what the ecosystems appear to be like (i.e., do the countries appear to be mountainous, coastal, deserts, forests, farmland, urban, etc.).
Although some students will be eager to ask you questions, it’s important to engage students in guiding dialogue to make sure they are critically considering their data as the interpret it. Otherwise, this lesson becomes simply collecting and compiling data. The learning objectives are met when they consider what this data means.
During the last 10 minutes, I ask for groups to volunteer answers to the final questions and to support their answers with specific data they gathered during the activity. If students used a map to answer the population density question, I ask what, specifically, they saw on the map that led them to that conclusion.