HotAIR - PHYSICS LESSON -- Bifocal Optics


Bifocal Optics

Yet another tool for teachers

by Alice Shirrell Kaswell, AIR staff

Bifocal glasses were invented by Benjamin Franklin

Some students believe that physics lessons are necessarily dull. Many of them complain about a "lack of clarity." Here is a memorable physics lesson that explores the notion of clarity.

The Lesson

The lesson was developed by Lawrence P. Calabrese, a science teacher at Silver Sands Middle School in Deland, Florida. It was described in the February 27 issue of the Daytona News-Journal. Here is a pertinent snippet:

DELAND -Volusia County School District officials are recommending a five-day suspension for a teacher accused of slapping a student on the buttocks....

The student said Calabrese tried to look down her shirt and made comments to the class that he is attracted to her and she is attracted to him. Her complaints came to light after she reported Calabrese had slapped her as she entered his classroom last November. Calabrese told investigators he did not touch the student intentionally and, if he touched her accidentally, he was not aware of it. He said his comments about being "attracted" to the student were made during a lesson about gravity and that he used the same example with different students in his other classes. As for the accusation that he attempted to look down the girl's shirt, Calabrese said he wears bifocals and, as he tilts his head to see properly, it could be misinterpreted, the report said.

"Linking Learning to Life"

This is the best kind of lesson -- it comes disguised as a fun newspaper report. Thus it is likely to engage students' interest, and to stimulate their curiosity.

The school has a motto: "Linking Learning to Life." This motto is the key to understanding the lesson.

How to Use This Lesson

We recommend that you get copies of the original newspaper article, and pass them out to your students.

The students, their curiosity firmly engaged, will then enjoy discussing this lesson.

Questions for Discussion

There are many scientific questions that can be raised. No doubt students will have many of their own. Here are a few questions that you can use to begin the classroom discussion:

1. What are bifocals?

2. How do the optics work?

3. Discuss the angle of incidence, and the angle of refraction. How are light rays affected differently by the two portions of a bifocal lens?

4. Draw a simple diagram of Mr. Calabrese, his bifocal lenses, the student's shirt, and the light rays that reach Mr. Calabrese's eyes.

For a further lively discussion, you can ask students to re-enact the demonstration, and then to explain what they have learned from all this.

(Thanks to investigator Michael Sylvester for bringing this to our attention.)

© Copyright 2001 Annals of Improbable Research (AIR)

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