Hands-on Activity: Catching the Perfect SAR Waves!
Educational Standards :
Pre-Req Knowledge (Return to Contents)
Students should be very comfortable working with the following concepts: the distance formula, types of triangles, and relationships between measurement of triangle sides and angles. Students should have prior knowledge of the triangle inequality theorem and recognize the distance and angle relationships formed from the radar, target and target's altitude. (The triangle inequality theorem may be explained while teaching the Pythagorean theorem equation since the equation clearly shows that one side of a triangle is always shorter than the sum of the other two sides.) All concepts, with the exception of the triangle inequality theorem are not required, but enhance th students' learning experiences. Pre-requisite knowledge may be used to scale the activity for higher levels.
Learning Objectives (Return to Contents)
After this activity, students should be able to:
Materials List (Return to Contents)
Each group needs:
To share with the entire class:
Introduction/Motivation (Return to Contents)
(Before students enter the classroom, with the projector off and classroom lights dimmed, open the Catching the Perfect SAR Wave Presentation [a PowerPoint file] to the title slide. From the title slide, click on "Play Multimedia" located on the lower part of the slide. This link plays sounds being generated from radio emissions from Saturn.)
As you walked in the classroom, were you intrigued by the sounds? What might these sounds be? What type of animals, instruments or natural phenomena might be making these sounds? (Give students to time to brainstorm ideas. Encourage them to use their imaginations. Turn on the classroom lights and have students share their ideas. After some guesses have been presented to the entire class, turn off the sounds.) Believe it or not, the sounds you heard are radio emissions coming from Saturn!
How is it possible to hear something from such a very great distance? (Expected responses: Baby monitors, telephones, two-way radios, antennas, satellites, and car radio and stereo.) You are all correct and all these devices use waves as the medium for sound! Is it possible to see an object far away with something blocking your view? (Student might take a little bit longer to answer, but expect answers such as: airport body scanners, MRI scanners, medical x-rays, and thermal imaging. Great, these are also all correct! Today we will be focusing on radar systems, which are used to see objects or topography from great distances. Radar systems also use waves as the medium to capture images. Radar imaging applications include examples such as military surveillance, terrain mapping and weather reporting. Radar imaging technology, developed by electrical engineers, provides structural terrain information to geologists for mineral exploration, reconnaissance and targeting information for military operations, and oil spill boundaries on water to environmentalists.
Today we will learn about the importance of the Pythagorean theorem in radar imaging systems! (At this point, start the presentation and let the journey of radar imaging begin.)
Vocabulary/Definitions (Return to Contents)
Procedure (Return to Contents)
Before the Activity
With the Students
(Note: Prior to day 1, students should have seed the PowerPoint presentation and and completed the worksheet.)
(Note: By day 2, students should have completed construction of the "radar" system prototype.)
Attachments (Return to Contents)
Assessment (Return to Contents)
Understanding the Problem: Have students complete the Understanding the Problem Worksheet, which is designed to reinforce their understanding about waves, the electromagnetic spectrum, radar systems and the Pythagorean theorem as it relates to engineering. At the end of the assessment, students are asked to restate their understanding of challenge/problem they are asked to solve in the activity.
Activity Embedded Assessment
A Mathematical Model: Have students complete the Mathematical Model, which provides a blank table and graph paper for student to collect and plot data. Student use their constructed sensor unit and record distance and the corresponding voltage reading. Independent and dependent variables are labeled on the table and graph.
Radar System Evaluation: Have students complete the Radar System Evaluation, which is designed to evaluate students' knowledge of the Pythagorean theorem. They are given clipart of a radar, target and target's altitude, which all together form a triangular model. They use the Pythagorean equation with two known side lengths on the triangular model to calculate the missing side length.
Activity Extensions (Return to Contents)
Have students calculate the percent error of the distances obtains from reading voltages to the actual distances calculated using the Pythagorean theorem. The equation to determine the percent error can be found on the Radar System Evaluation.
Activity Scaling (Return to Contents)
References (Return to Contents)
"Viewing Radio Waves." Teachers' Domain. 31 Oct. 2011. Web. 28 Jun. 2012.<http://www.teachersdomain.org/resource/npe11.sci.phys.energy.viewradiowaves/>.
Photo Dept. NASA Headquarters, 300 E. St. SW, Washington, DC 20546 http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4399
"Radio Waves & Electromagnetic Fields." Teachers' Domain. 19 Apr. 2007. Web. 29 Jun. 2012. <http://www.teachersdomain.org/resource/hew06.sci.phys.energy.radiowaves/>.
"The Electromagnetic Spectrum" NASA Mission: Science. 20 June. 2012. Web. Web. 29 Jun. 2012. <https://mynasadata.larc.nasa.gov/ElectroMag.html/>
"Video Tour of Electromagnetic Specturm." NASA Mission: Science. 20 June. 2012. Web. Web. 29 Jun. 2012. http://missionscience.nasa.gov/ems/emsVideo_01intro.html/
"Imaging with Radar." Teachers' Domain. 29 Jan. 2004. Web. 29 Jun. 2012. <http://www.teachersdomain.org/resource/phy03.sci.phys.energy.radar/>.
ContributorsLuis Avila, Mounir Ben Ghalia
Supporting Program (Return to Contents)RET-ENET Program, Electrical Engineering Department, University of Texas-Pan American
Acknowledgements (Return to Contents)
This activity was created through the University of Texas-Pan American's Electrical Engineering Research Experiences for Teachers in Emerging and Novel Engineering Technologies (RET-ENET) Program with support from National Science Foundation grant number CNS-1132609. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.