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RadTown Radiation Exposure Activity 2: Sources of Annual Radiation Exposure

Radiation Exposure Activity

Radiation Exposure Image

How much radiation are we exposed to every year? What about 30 years ago? The National Council on Radiation Protection and Measurements (NCRP) commissioned two studies in 1987 and 2009 to determine Americans’ exposure to radiation by type. Help your students explore different sources of radiation exposure using this math-focused activity. This activity is intended for middle and high school students.

On this page:


Students will:

  • Predict and graph Americans’ annual exposure to natural (background) and man-made radiation sources.
  • Compare their predictions to data from the National Council on Radiation Protection and Measurements (NCRP).
  • Define and classify sources of radiation exposure.

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Next Generation Science Standards

The concepts in this activity can be used to support the following science standard:

  • PS4. Waves and Electromagnetic Radiation

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Materials and Resources

Each italicized document title can be found at the bottom of this page, and is available for printing and distribution.

  • Radiation Exposure: Teacher Background Information
  • Vocabulary Materials
  • Annual Radiation Exposure — 1987 and 2009 pie charts; display using computer and projector
  • Annual Sources of Radiation Exposure Pie Chart Worksheet (one per student, pair or group)
  • Colored pens, pencils or markers
  • NCRP Sources of Radiation Exposure — 2009 pie chart (optional)
  • Relative Doses from Radiation Sources diagram (optional)
  • Student computers with Internet access (optional)

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  • 45-60 minutes, not including optional activities or extensions.

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  • Cosmic radiation
  • Dose 
  • Ionizing radiation
  • Man-made radiation
  • Natural (background) radiation
  • Radiation
  • Radon
  • Rem
  • Terrestrial radiation

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  1. Start with a vocabulary activity if students are not familiar with radiation and the terms used in this activity, or provide students with the terms and definitions.
  2. Ask students whether we can control our exposure to radiation? The answer is both “no” and “yes.” Radiation can come from natural and man-made sources. Natural (background) radiation is all around us and has been since the earth formed. We cannot control our exposure to natural cosmic (from space) radiation and terrestrial (from the ground) radiation. When made aware of the presence of radiation through testing or monitoring results, warning signs, labels and notices, we can make choices that limit our exposure. For example, people can fix high radon levels in homes, distance themselves from radioactive sources, and wear protective equipment and follow regulations when handling or being near a radiation source.
  3. Explain that the word “radiation” generally brings to mind nuclear power plants, nuclear weapons, or medical procedures, tests and treatments. However, radiation is part of our daily lives. Our bodies are well adapted to handle some exposure to radiation. We can also benefit from some sources of radiation in moderation, such as the sun. There are benefits from the use of x-ray machines that can tell us if something is wrong within our body and other medical radiation sources used to treat diseases like cancer.
  4. Share the Annual Radiation Exposure — 1987 pie chart. Explain to students that are unfamiliar with a pie chart that pie charts are circular graphs divided into sections that represent parts of the whole. Explain that the pie chart is based on data the NCRP collected in 1987. The chart shows that Americans’ average annual exposure to radiation in 1987 came from 82 percent of natural (background) radiation and 18 percent of man-made radiation. The pie chart is further broken down to show exposure by more specific sources of natural and man-made radiation.
  5. Provide students with the Annual Sources of Radiation Exposure Pie Chart Worksheet. Review the example provided and the directions. Answer any questions. NOTE: Students can include the different types of natural and man-made radiation in the pie chart for more complexity if desired.
  6. Display students’ pie charts and the Annual Radiation Exposure — 2009 pie chart. Have students compare their pie charts to the 2009 pie change and discuss:
    • How their pie chart compares to or differs from their classmates’ pie charts and the NCRP’s 2009 pie chart.
    • Reasons for any large differences.
  7. Conclude by having students answer the following questions (verbally or in writing): What differences do you see between the 1987 and 2009 pie charts?
    • What do you think are the reasons for those differences?
    • What information was most surprising to you?
    • Did this activity confirm or change your perceptions and beliefs about radiation exposure? Explain your response.
  8. Optional activities or extensions:
    • Explain that, in the United States, radiation exposure is usually expressed in units called rems or millirems (mrem). (1000 mrem = 1 rem). In 1987, the NCRP found that Americans were exposed to 320 mrem per year from all sources of radiation. In 2009 the exposure rate increased to 620 mrem per year. Have students:
      • Examine the Relative Doses from Radiation Sources diagram. Identify potential sources that can increase a person’s exposure to radiation (e.g., certain medical procedures or living in areas with higher than average radon levels).
      • Have students examine the Annual Radiation Exposure – 1987, Annual Radiation Exposure – 2009 and NCRP Sources of Radiation Exposure—2009 pie charts and discuss the changes that have led to the average increase in radiation exposure from 320 to 620 mrem per year. Note the significant increase in medical radiation and the types of medical radiation used.
    • Consider the increased use of medical radiation to detect and treat diseases and discuss whether the benefits outweigh the potential risks of exposure. Have students complete a pie chart based on their prediction of Americans’ exposure to natural (background) and man-made radiation in the next 10 or 20 years.

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Common Core State Standards (CCSS)

The concepts in the Sources of Annual Radiation Exposure activity align with the following:

  • CCSS Language Arts Standards for Literacy in History/Social Studies, Science, & Technical Subjects:
    • CSSS.ELA-Literacy.SL.6-12.2 Comprehension and Collaboration
    • CSSS.ELA-Literacy.RST.6-12.4 Craft and Structure
    • CSSS.ELA-Literacy.RST.6-12.7 Integration of Knowledge and Ideas
  • CCSS Mathematics Standards:

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Printable Worksheets and Classroom Aides

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