Tom McNulty
June 28, 1999

Lesson Plan

Title of Lesson:  Sources and Uses of Radiation.

Audience: 11th Grade Physics.

Duration:  Approx. 45 minutes.

References:  Physical Science, Hurd, etal. Ch. 11, pp. 256-262.
                       Physics: A General Introduction, 2nd ed. Van Heuvelen, Alan. Ch.34, pp. 730-735.

Specific Behavioral Objectives:

  1. Students will be able to describe at least three natural and four man-made sources of radiation.
  2. Students will be able to explain the importance of measuring background radiation when determining the radioactivity of a sample.
  3. Students will be able to describe at least five ways in which radiation is used for practical purposes.
Materials:
  1. Fiestaware plate
  2. Geiger counter
Anticipatory Set:  Introduce students to the Geiger counter by taking a count of background radiation. Ask them where this radiation comes from. After a 2-3 minute count, pull out the Fiestaware plate and count it for 2-3 minutes. Ask the students why the counts are higher (if they are higher) for the plate than for the background. "We'll learn about some more radiation sources today, as well as some ways in which radiation can be put to use."

Main Body:

                   SOURCES OF RADIATION

    1. Cosmic rays - from the sun, stars, etc.
    2. Certain foods - foods rich in potassium, such as bananas, salt-substitutes, and some salad dressings.
    3. Terrestrial - radioactive isotopes are present in the crust of the earth, building materials, etc.
    1. Nuclear reactors - radiation is given off from fission reactions as well as from radioactive waste.
    2. Nuclear bombs/fallout - bomb testing from 1950's and 1960's.
    3. Medical - X-rays, cancer treatment, tracers.
    4. Household items - glow in the dark watches, smoke detectors, etc.
BACKGROUND RADIATION USES OF RADIATION
    1. Carbon-14 - used to date organic material thousands of years old.
    2. Potassium-40 - used to date certain rocks up to billions of years old.
    1. X-rays
    2. Radioactive tracers
    3. Cancer treatment
    1. Meat sterilization
    2. Luminescent wrist watches
    3. Engineering inspections of welds, bridges, etc.
ACTIVITY Evaluation:  Students will receive verbal feedback on concept mastery by responding to questions and participating in a brief review session. Areas of confusion will be retaught or clarified.

Assignments:

Summary/Closing Statement:  Today, we saw that radiation is all around us. It occurs both naturally and from man-made sources. What are some of the sources we talked about today? We also discussed background radiation. What is background radiation? Why do we need to measure it? Would background radiation be the same in Denver, Colorado as it is here in southwestern Pennsylvania? Why not? Finally, we talked about some uses for radiation. What were some of those? Radiation can also be very damaging to living tissue. Next time, we'll find out what radiation does to living cells and some ways to minimize your exposure to it.
 

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Copyright 1999, Thomas McNulty
Last updated 9 August 1999