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Active Astronomy: Classroom Activities for Learning About Infrared Light

Instructions for Downloading: Active Astronomy files are in PDF format and require Acrobat Reader Plug-in (free). Activity sheets, student tests and answer sheets are also available in Microsoft Word™ to allow you to modify these materials to best suit your students.

Materials: Active Astronomy requires common classroom materials as well as specific electronic components and color filters (gels). For details, see the "Suggested Vendor List" available in Section 1 of Active Astronomy or as a separate PDF file. open PDF file
Vendor List
Errata List : If you have the Active Astronomy Classroom Activities CD-ROM, you should download the Errata pdf file. Some of the URL links in the CD-ROM documents have changed since the CD-ROM was created. This Errata List gives the correct links for the documents on the disk.
pdf file icon76K Errata List

Link to information about the University of Chicago Yerkes Observatory's implementation and modification of the Active Astronomy kits targeted especially for students with visual or auditory impairments:


Download Complete File of Active Astronomy: Three files make up the complete set of materials for Active Astronomy.
1. Sections 1-5 Activity sheets, tests, and answer sheets pdf file icon2.7MB Image of teachers
2. Image file for Section 2 pdf file icon592K
3. Image file for Section 5 pdf file icon876K
If you have a slow connection or printer, you may wish to download each section separately (below).

Download individual sections of Active Astronomy:

Section 1

Overview and Assessment pdf file icon572K

This section contains an overview of the activities, including materials and preparation, relevant portions of the National Science Education Standards and AAAS's Benchmarks for Science Literacy, common student misconceptions, the student test, and the role of infrared light in astronomy. The PDF file contains parts 1.1 through 1.5.


Modifiable Word Documents:

Learning About Infrared Light Student Test MS Word file icon32K

Student learning about color spectrum
1.3 Learning About Infrared Light Student Answer Sheet MS Word file icon32K

Learning About Infrared Light Teacher Answer Key MS Word file icon32K

Section 2

What's Getting Through?pdf file icon300K

Students are introduced to light and colored gels (filters). Students make and test predictions about light and color using gels, by looking at messages written with differently colored crayons on differently colored paper with differently colored gels. Students then learn about the importance of gels (filters) to astronomers by looking at an astronomical image through red and blue gels and comparing the parts of the image that are enhanced by the gels. Then, they analyze images taken with regular and infrared cameras to see that objects opaque to light at one wavelength may be transparent to light of a different wavelength.The PDF file contains parts 2.1 through 2.3.


Modifiable Word Documents:

Student Activity Sheet MS Word file icon92K

Crab Nebula



Teacher Answer Key MS Word file icon156K


2-Images Images:
Images to support activities in Section 2
pdf file icon592K

Section 3

Sensing the Invisible pdf file icon632K

Just as our ears cannot hear all wavelengths of sound, our eyes cannot see all wavelengths of light. Students build a photocell detector, and use it to detect different colors of light in a spectrum. Then they place the detector just outside the red region of the spectrum and see that the detector detects the presence of light there, even though there is no color visible. Students learn that "invisible light" exists and that we can detect this light with instruments other than our eyes. In a final part of the activity, students investigate the IR signals emitted by TV and VCR remote controls. The PDF file contains parts 3.1 through 3.3.


Modifiable Word Documents:

Student Activity Sheet MS Word file icon632K

Photocell detector sensing visible 

Teacher Answer Key MS Word file icon632K


Section 4

Reflection pdf file icon248K

Students learn that infrared light is reflected in the same manner as visible light. Students align a series of mirrors so that they can turn on a TV with a remote control when the remote is not in a direct line with the TV. As a result of their experiment with reflection, students deduce that infrared light is another form of light and is a part of the electromagnetic spectrum. The PDF file contains parts 4.1 through 4.3.


Modifiable Word Documents:

Student Activity Sheet MS Word file icon36K

Kids doing activity

Teacher Answer Key MS Word file icon36K


Section 5

Listening to Light pdf file icon608K

Students learn that light carries information and that infrared (IR) radiation is a form of light that in some cases behaves like visible light and other cases behaves very differently. Students first see how a photocell (solar cell) can be used to detect the presence of light. They then learn how the photocell reacts to light from a laser pointer (or other laser) and a remote control, and see that information, for example a message, can be transmitted by visible and infrared light. They listen as an infrared-emitting diode is used to transmit music from an audio source (like a CD player) to the photocell with a speaker connected to it. Finally, students test the effects on the transmission of music when various objects are placed in between the infrared emitting diode and the photocell. They learn that some objects that block visible light allow infrared light to pass through. The PDF file contains parts 5.1 through 5.3.




Modifiable Word Documents:

Student Activity Sheet MS Word file icon40K

Photocell detector parts


Teacher Answer Key MS Word file icon44K

5-Images Images:
Images to support activities in Section 5
pdf file icon876K

(Aug 25, 2003)



Supplementary Information - for teachers and students interested in delving more deeply into electronics, here is supplementary information about electrical components in the Infrared transmitter circuit:

  1. Reference material about capacitors, the crucial component in this circuit pdf file icon303K
  2. The IR transmitter circuit re-drawn with text explanation by Yerkes Observatory (U. Chicago) electrical engineer Jesse Wirth pdf file icon 41K

Related Laboratory Experiment:
  Perform a version of the experiment of 1800, in which a form of radiation other than visible light was discovered by the famous astronomer Sir Frederick William Herschel. The experiment appears on the Spitzer website; it involves using a prism and thermometers to detect infrared light in the same manner as Herschel. Go to the Spitzer website for details
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