Menacing Microbes Unit Driving Question: How does a community get ready for an outbreak?

There’s an Outbreak! Lesson Driving Question: How do diseases spread?

1. Introduce students to the practice of using four-level analysis to interpret patterns in a map.

  • Tell students that one of the ways that people solve problems is to look for patterns of data in maps. A useful technique for this is called four-level analysis.
  • Draw a large version of the Four-Level Analysis Tool on the board. This should mirror the image on the student handout–a four-square table, each square labeled with a Roman Numeral (I–IV).
  • Display the NASA map of the Earth at night.
  • Guide the students through a Think-Pair-Share discussion about the projected map using the following four-level analysis questions:
      • What are you looking at? Where is this? When is this?
      • What patterns do you see?
      • Why does the map look like this? What are some possible explanations for these patterns?
      • Why is this important? What will you remember?
  • Record student responses in the appropriate squares on the large version of the tool.
  • Tell students that maps can be a useful tool for identifying the source of a disease outbreak.


2. Use the case of John Snow to learn how maps can locate the source of an outbreak.

  • Introduce students to John Snow by having them watch 06:06–7:55 of the Geospatial Revolution video.
  • Complete the epidemic Mapping a London Epidemic activity to identify what patterns John Snow might have noticed in order to find the location of the source of the epidemic. This is a stand-alone activity that can either be used in its entirety or by having students complete the following three exercises:
      • Mapping a London epidemic
      • Cholera deaths in Soho
      • Water pumps in Soho
  • After completing the activity, have students share what they notice about the different maps.


 3. Analyze disease maps to identify patterns in the data.

  • With their selected map in front of them, distribute the Four-Level Analysis Tool to each pair of students. Have students respond to the following on their Four-Level Analysis Tool:
      • Level I: What are you looking at? Where is this? When is this?
      • Level II: What patterns do you see?
      • Level III: Why does the map look like this? What are some possible explanations for these patterns?
      • Level IV: Why is this important? What will you remember?


4. Share the analysis with others to compare information on the maps.

Have each pair of students share their analysis with another pair of students.

  • If pairs are comparing the analysis of the same map, have students discuss what was different about their analyses (e.g., explanations for the patterns, reasons why this is important).
  • If pairs are comparing an analysis of different maps, ask them to discuss what was different about the maps (e.g., location, scale, interactivity). 

Informal Assessment

Collect the Four-Level Analysis Tool to assess students’ understanding of the method, and the depth of their analysis.

Extending the Learning

If technology is available, The John Snow Story Map uses a GIS heat mapping technique.  

Subjects & Disciplines

Learning Objectives

Students will:

  • Identify patterns in disease outbreak maps.

Teaching Approach

  • Project-based learning

Teaching Methods

  • Discussions
  • Multimedia instruction
  • Reading

Skills Summary

This activity targets the following skills:

Connections to National Standards, Principles, and Practices

Common Core State Standards for English Language Arts & Literacy

The College, Career & Civic Life (C3) Framework for Social Studies State Standards

  • D1.His.14.6-8:  Explain multiple causes and effects of events and developments in the past.
  • D2.His.16.6-8:  Organize applicable evidence into a coherent argument about the past.
  • D2.His.1.6-8:  Analyze connections among events and developments in broader historical contexts.

What You’ll Need

Required Technology

  • Tech Setup: 1 computer per classroom, 1 computer per pair, Projector

Physical Space

  • Classroom


  • Heterogeneous grouping
  • Homogeneous grouping
  • Jigsaw grouping
  • Large-group instruction
  • Large-group learning
  • Small-group instruction
  • Small-group learning
  • Small-group work

Background Information

Once a disease outbreak has been reported, it is important to identify the source of the outbreak so that a response team can stop the spread of the disease. Epidemiologists often use map data to find the source of outbreaks. There are many different modern techniques for this such as GIS mapping. A historical example of this kind of mapping is the case of John Snow, an epidemiologist who used maps to trace the source of a cholera outbreak to a single water pump.


A method that people use for analyzing maps is called four-level analysis. This is a method that seeks to understand not only what patterns exist on a map, but why they are happening and what might happen next. Geographic patterns and processes are emphasized in advanced high school geography courses. Learning this method can be a valuable skill in preparation for this kind of course work.

Prior Knowledge

  • None



infectious, sometimes fatal disease that harms the intestines.


disease-producing agent, like a virus or bacteria; can also refer to the disease itself or the transmission of the disease.


to poison or make hazardous.


harmful condition of a body part or organ.


outbreak of an infectious disease able to spread rapidly.


sudden occurrence or rapid increase.

Instructional Content