Detection Detective

Author: Sarah Kenyon

Time: 2-3 class periods
2.5 hours for creation of teacher-generated station and setting up student generated stations as well as photocopying worksheets.
Materials: Stations (student and teacher generated)
Student activity sheets


This activity revisits the biomedical imaging techniques that students investigated in their explore activity and seeks to further explain these techniques using physical principles. Students are asked to organize these techniques in terms of type of wave, wavelengths (in EM related methods) and to explain the efficacy of methods based on materials interacting with these rays. Both student-generated informational posters from the explore activity and teacher-generated stations exploring the fate of rays when interacting with materials (absorption, reflection, transmission) and the properties of the materials themselves will be used to help students fill out provided activity sheets.

Students will:
1. Describe what each detection method uses (compression waves, matter radiation, EM radiation) and rank the wavelengths of each if appropriate.
2. Answer questions about absorption, importance of materials and explain differences. Make sure they describe diagnostic uses of each method in the first lesson

National Science Standards
Content Standard A: Scientific Inquiry
Identify questions that guide scientific inquiry
Content Standard B: Physical Science
Structure and properties of matter
Content Standard E: Science and Technology
Identify a problem or design an opportunity
Communicate the problem, process, and solution
Content Standard F: Science in personal and social perspectives
Personal and community health
Natural and human-induced hazards
Science & Technology in local, national and global challenges

Teacher Background
Teacher Background: EM, waves, Photoelectric effect supplement
Teacher stations 1, 2, 3-5 supplements. These are taken from the information below in related and resource websites

Resource Websites

While these pages concentrate on remote sensing, they give some background in the fates of radiation interacting with a material. The second page has a great visual of the EM spectrum, sizes of waves, and examples of what emits each radiation type: http://rst.gsfc.nasa.gov/Intro/Part2_3.html, http://rst.gsfc.nasa.gov/Intro/Part2_4.html

This site addresses solar radiation, is easy to read and includes good pictures (look through the pages): http://landsat.usgs.gov/resources/remote_sensing
Additionally, information listing interactions with materials (and good for Remote Sensing info for students investigating this type of imaging): http://landsat.usgs.gov/resources/remote_sensing/remote_sensing_applications.php

General background of radiation interacting with various materials. Has a very useful tutorial with answers: http://www.glenbrook.k12.il.us/GBSSCI/PHYS/CLASS/light/u12l2c.html

It is recommended that some or all of these resources be available to students to help answer questions based on materials and their interaction with incident rays. These mostly deal with infrared and visible light. The following resource has information on the interaction of other wavelengths of light with atoms: http://hyperphysics.phy-astr.gsu.edu/hbase/mod3.html




Biomedical imaging and the EM spectrum:
1) As students enter the classroom, ask them the following questions: “As you saw in your previous class, there are a number of different imaging techniques- some biomedical, some not. You and your classmates made posters/presentations earlier in this lesson set. Did you see similarities or differences among different techniques? How would you classify the different imaging techniques?” Tell students they may turn to their neighbor after the first 5 or so minutes to discuss and help inform their answers.

2) Give the students a small lecture based on the Teacher Background: EM, waves, Photoelectric effect supplement.

3) Have a transparency of the EM spectrum on the board. Make sure you address the following:
a. Waves vs. particles
b. Rays and radiation
c. Wavelength, frequency and amplitude
d. General origins of each section of the EM spectrum.

4) Tell students that they will have the opportunity to rotate through stations describing each of the methods. Have two final stations that are internet research stations in case they need more information than is included in the student generated stations. Each station will be what the groups put together in the first lesson. Make sure they have adequately described diagnostic uses of each method in the first lesson, otherwise, this might be an extra day in this learning cycle.

5) Have students work individually to fill out an activity sheet that describes what each detection method uses (compression waves, matter radiation, EM radiation) and order the wavelengths of each if appropriate.

6) Afterwards, have them rotate through two identical teacher-generated stations regarding reflectance, transmittance, absorption and the importance of different materials. Have them answer questions on their activity sheets.

7) At the end of the activity, have students meet in groups of 4 and use a heads together/minds together technique. [In this technique, each group is assigned a number, and each student a number within their group. Students get an appropriate amount of time to discuss answers to provided questions in their group. The teacher then spins a dial for a student number and all the students with that number stand up (i.e. all Student #3 from all groups) and then the teacher will spin a second dial to determine the student who will orally answer the question (i.e. group #4). The remaining students still stand and will be asked to vote when the answering student is done with her/his presentation. A thumbs-up shows they agree with the answer, a thumbs-to-the-side that they basically agree but have something further to contribute, a thumbs-down that they disagree (and must explain why to the class). For the next question, the teacher spins again.

8) As homework, make sure they complete their activity sheets.

Students may need time to complete the activity sheet at home.


Embedded Assessment
In the heads together/minds together activity, teachers can assess group answers and accuracy, or they can indirectly assess based on participation and collaboration. This activity allows students to use numerous skills- individual research and evaluation in station rotations, reading skills, synthesis skills, as well as group collaboration and cooperation skills.
The completed activity sheets provide opportunity for assessment.


PULSE is a project of the Community Outreach and Education Program of the Southwest Environmental Health Sciences Center and is funded by:

NIH/NCRR award #16260-01A1
The Community Outreach and Education Program is part of the Southwest Environmental Health Sciences Center: an NIEHS Award


Supported by NIEHS grant # ES06694

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Last update: November 10, 2009
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