AAPT Logo
TPT Logo
 
   
 

The Physics Teacher -- September 2011 -- Volume 49, Issue 6, pp. 368

Infrared Imaging for Inquiry-Based Learning

Charles Xie and Edmund Hazzard

The Advanced Educational Modeling Laboratory, The Concord Consortium, Concord, MA

Full Text: Read Online (HTML) | Download PDF FREE | View Cart
Based on detecting long-wavelength infrared (IR) radiation emitted by the subject, IR imaging shows temperature distribution instantaneously and heat flow dynamically. As a picture is worth a thousand words, an IR camera has great potential in teaching heat transfer, which is otherwise invisible. The idea of using IR imaging in teaching was first discussed by Vollmer et al. in 2001.1–3 IR cameras were then too expensive for most schools. Thanks to the growing need of home energy inspection using IR thermography, the price of IR cameras has plummeted and they have become easy to use. As of 2011, the price of an entry-level handheld IR camera such as the FLIR I3 has fallen below $900 for educators. A slightly better version, FLIR I5, was used to take the IR images in this paper. As easy to use as a digital camera, the I5 camera automatically generates IR images of satisfactory quality with a temperature sensitivity of 0.1°C. The purpose of this paper is to demonstrate how these affordable IR cameras can be used as a visualization, inquiry, and discovery tool. As the prices of IR cameras continue to drop, it is time to give teachers an update about the educational power of this fascinating tool, especially in supporting inquiry-based learning.

© 2011 American Association of Physics Teachers

Acknowledgment

This work is supported by the National Science Foundation (NSF) under grant number 0918449. Any opinions, findings, and conclusions or recommendations expressed in this paper, however, are those of the authors and do not necessarily reflect the views of the NSF. The authors are indebted to the reviewer for generously permitting us to incorporate his/ her ideas of the Fermi calculation into this paper.

Article Outline

  1. Science experiments
  2. Engineering projects
  3. Summary

KEYWORDS and PACS

Keywords

cameras, heat transfer, infrared imaging, physics education, student experiments

PACS

  • 01.50.Pa

    Laboratory experiments and apparatus

  • 07.07.Df

    Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

  • 07.57.Kp

    Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors

  • 07.68.+m

    Photography, photographic instruments; xerography

  • 44.00.00

    Heat transfer

PUBLICATION DATA

ISSN

0031-921X (print)  

Publisher

$abstract.society.value is a Member of CrossRef American Association of Physics Teachers

ARTICLE DATA

Digital Object Identifier
http://dx.doi.org/10.1119/1.3628268

  1. M. Vollmer, K. -P. Möllmann, F. Pinno, and D. Karstädt, “There is more to see than eyes can detect,” Phys. Teach. 39, 371–376 (Sept. 2001)PHTEAH000039000006000371000001.
  2. K. -P. Möllmann and M. Vollmer, “Infrared thermal imaging as a tool in university physics education,” Eur. J. Phys. 28, S37–S50 (2007).
  3. M. Vollmer and K. -P. Möllmann , Infrared Thermal Imaging: Fundamentals, Research and Applications, 1st ed. (Wiley-VCH, Berlin, 2010).
  4. en.wikipedia.org/wiki/Latent_heat.
  5. M. Holladay , “Thermal bridging,” Fine Homebuilding 16–17 (April/May, 2010).
  6. C. Xie, “Visualizing chemistry with infrared imaging,” J. Chem. Educ. 88, 881–885 (2011).


Figures (click on thumbnails to view enlargements)

FIG.1
Using an IR camera to visualize heat conduction on a plate consisting of areas with different thermal conductivities. A hot water jar was used as the heat source and then removed for observation in three cases: (a) The jar was placed above the center of the metal strip, (b) the jar was placed entirely above a cardstock strip, and (c) the jar was placed half on the metal strip and half on a cardstock strip. The IR images were taken immediately after the jar was removed. Image (c) is a close-up. The emissivity factor of the camera was set to 0.8. In an IR image, the number at the upper-left corner is the temperature of the spot to which the crosshair points (it acts like an IR thermometer). The numbers at the bottom are the lower and upper bounds of the temperature. The IR camera automatically sets the bounds based on the lowest and highest temperature it detects in the view. These images use the “Iron” color palette of the FLIR I5 camera (see the heat map bar at the bottom of each image for a reference).

Export Figure to PowerPoint

FIG.2
Visualizing the natural convection of air. Top: an apparatus for taking a “slice view” of the three-dimensional temperature field by intercepting heat with a rotatable screen. Bottom: a sequence of IR images that shows the rising heat plume. These images use the “Rainbow” color palette of the FLIR I5 camera. The temperature range is 24°C –100°C.

Export Figure to PowerPoint

FIG.3
(a) A hot/cold water jar was placed in front of a piece of paper used as the “radiation projection screen.” All the IR images (c–f) were taken from the other side of the screen. (b) The jar was wrapped with aluminum foil. (c) A warm area emerged after a hot water jar was placed. (d) The warm area became insignificant after the hot water jar was wrapped. (e) A cool area emerged after a cold water jar was placed. (f) The cool area became insignificant after the cold water jar was wrapped.

Export Figure to PowerPoint

FIG.4
Visualizing latent heats of condensation and evaporation. (a) The experimental setup is as simple as placing a piece of paper above a cup of water. (b) Shortly after a piece of paper was placed on top of the cup, the part of the paper above water warmed up. (c) A minute later, the temperature of the paper became the same everywhere. (d) The paper was removed from the cup and the area immediately cooled down. (e) IR imaging shows that part of the paper warmed up and part of it cooled down when it was shifted. All four IR images were shot from the top. The perimeter appeared to be cooler due to the heat conduction through the edge of the cup when the paper was on top of it (because water in an open cup is always slightly cooler than room temperature due to the evaporative cooling effect).

Export Figure to PowerPoint

FIG.5
An experiment that shows a possible “heat concentration” effect in a pyramid when a heater (a 40W light bulb) was placed on the floor inside to heat it up.

Export Figure to PowerPoint

FIG.6
Demonstration of thermal bridging. A short nail was inserted into the back wall of a heated scale model house, shown on the left, to create a thermal bridge. The IR image on the right shows heat loss through it (the lower bright spot).

Export Figure to PowerPoint

FIG.7
Using an IR camera to reveal the thermal signature of a simple model house heated by a light bulb inside it. Left: a model house with a ceiling. Right: a model house without a ceiling.

Export Figure to PowerPoint

FIG.8
A blower-door test for a model house. Left: a computer fan was fit into a square opening on the wall of a model house heated by a light bulb inside. On the opposite wall, a small hole was punched to simulate a crack. Center: an IR image taken when the fan was off reveals exfiltration. Right: an IR image taken when the fan was on reveals infiltration.

Export Figure to PowerPoint



Close

Your Recent History Recent History Help

Recently Viewed

  1. Infrared Imaging for Inquiry-Based Learning
  2. The “Green Lab”: Power Consumption by Commercial Light Bulbs
  3. Wikis as a Teaching Tool in Physics Classrooms
  4. A Simple Experiment to Explore Standing Waves in a Flexible Corrugated Sound Tube
  5. Optics Demonstration with Student Eyeglasses Using the Inquiry Method

AAPT on:

close