The Case of the Missing Gerbil

With the widespread availability of camcorders, more powerful computers, devices capable of storing very large files, and inexpensive digital video editing programs, we anticipate an increase in the classroom use of original video productions.

Most of the classroom examples we provide describe what students can do with technology. This feature is different because the emphasis is on how teachers used technology to produce instructional materials. We feel this example is creative and actively engaged students.

Background

This example was developed by Cully Gause and colleagues for a middle school life science course. Cully had purchased a laboratory "kit" to demonstrate electrophoresis - a laboratory procedure in which a small electrical current carries molecules through a special gel. Different sized molecules move through the gel at different rates and over time the molecules from an unknown substance separate into distinctive bands (see image at the bottom of this page). One application of this technique is to match the pattern of bands from an unknown substance with the pattern from a known substance. This is one method by which an unknown (e.g., a sample found at a crime scene) is matched against samples collected from suspects.

Cully faced two basic challenges:

• he had a single laboratory kit and several classes of students, and
• he needed to find a way to help students follow the process of inquiry involved in this research procedure.

The Video Activity

The activity developed in response to these challenges was a video. The video follows the adventures of Cully and his assistant (the student teacher) as they investigate the disappearance of a classroom pet - the gerbil.

The video begins as Cully discovers the "crime"! Soon Cully is off to interrogate several school personnel who provide both logical and illogical reasons they could not possibly be the gerbil snatcher. During a more thorough investigation of the crime scene, Cully's assistant locates some drops of what appear to be blood. Perhaps the culprit was cut dragging the gerbil from its cage or perhaps the gerbil bit the abductor before being subdued!

This complex scenario was established to provide a context for a demonstration of the electrophoresis technique. Cully is soon off to collect samples from his prime suspects (a momentary suspension of belief is required at this point - obviously no teacher actually donates blood). The video then presents a demonstration of the actual electrophoresis technique (using materials supplied with the kit).

Discussion

Students knew the video was a spoof, but it still had the desired effect. The use of their own school as the setting allowed students to recognize and hypothesize about the crime scene. The "suspects" were familiar people in unfamiliar roles and watching their teachers behave in uncharacteristic ways seemed to maintain the attention of the middle school students. The full video (we provide only selected segments here) contains some very funny material - e.g., after asking the head cook if she could account for her whereabouts, Cully casually asks if any unusual meat entrees appear on the day's lunch menu.

The electrophoresis demonstration followed the procedure outlined in the laboratory manual. The exception was the labeling of the comparison samples with the names of the suspects.

The test was not interpreted for the students, but they were asked to reach their own conclusions.

The following is the original "Missing Gerbil" video. Click the forward arrow to begin. Note: The video is small because it was created some years ago using analog video that was converted to video. At the time online video tended to be presented in a smaller format because of slower download speeds. We continue to use this example because we continue to believe it is one of the most interesting teacher generated projects we have encountered.

The video created by teachers [video]

Here teacher Cully Gause comments on his purpose in creating this video.

Interview with Cully Gause [video]

Be patient if nothing appears in this space - a video file is downloading in the background. This video requires the Apple Quicktime plugin (download).

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