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Grad students light the way for sixth-graders

Dew Hongpinyo, a graduate student and member of Lehigh's student chapter of SPIE, explains the workings of the eye to students at Springhouse Middle School in Allentown.

The TV mounted on the wall of Dina Dewald’s classroom at Springhouse Middle School in Allentown periodically displays a flash image announcing students’ achievements. Every 15 minutes or so, you can read who has been chosen student of the month and other news of the day.

The two dozen students in Dewald’s sixth-grade science class were not distracted by the TV on Monday, Nov. 17, when seven graduate students in electrical engineering came to visit from Lehigh.

Instead, the sixth-graders paid steady attention as the Lehigh contingent demonstrated some of the scientific concepts behind the inner workings of TVs, the internet and other marvels of the modern communications age.

The graduate students—members of Lehigh’s student chapter of the International Society for Optical Engineering (SPIE)—taught four 20-minute units on topics in optics to two sixth-grade science classes at Springhouse.

This is the second consecutive year the SPIE students have taught at Springhouse. The contact was established with help from Boon S. Ooi, professor of electrical and computer engineering, whose son attends Springhouse.

The SPIE students asked the sixth-graders a range of questions. Some were simple—name the colors of the rainbow. Others required preparation—describe the difference between convex and concave lenses. The queries prompted a sea of raised hands as the kids raced to be the first to answer.

“This is great,” said sixth-grade teacher Jim Haines, whose students also attended the optics units. “The kids get to learn by handling things.”

“This experience is very helpful for us,” said Allison Ding, the president of the SPIE chapter. “Because this is our professional area, we typically use technical language. This helps us learn how to use more friendly language when we introduce technical concepts to other people.

“Also, the kids are full of imagination. They see different aspects of the technology. This helps us come up with new ideas.”

In the unit on lenses and images, Vitchanetra “Dew” Hongpinyo, treasurer of the SPIE chapter, described the function of each part of the eye and reviewed the differences between far- and near-sightedness. Hongpinyo later asked the kids to figure out whether a convex lens, which converges lightwaves, or a concave lens, which diverts them, would more effectively start a fire by focusing the rays of the sun.

Clara Dimas, past president of the SPIE chapter, showed the sixth-graders how to find images in convex and concave lens systems by sliding the lenses along a meter-stick between a light source and a piece of paper.

Shedding light

Ding discussed the principles of light transmission and speed, as well as the critical importance of light reflection and refraction (bending) in the cutting of a diamond.

A session on light polarization was taught by Kangbaek Kim and Chee-Loon Tan, and a session on color sensing was led by Yik-Khoon Ee, SPIE vice president, and Hongping Zhao, SPIE secretary.

As a lightwave travels, the sixth-graders learned, it also oscillates, or trembles. This polarization can be linear, circular or elliptical, and it can occur horizontally or vertically. The students held a piece of calcite over the textbooks to observe the faint double image that results when the stone bends light in two directions depending on its polarization.

In the session on color sensing, the students learned about two types of light—infrared and ultraviolet—which are felt but which cannot be detected by the human eye. They learned that additive color is generated by a light source such as an LED (light-emitting diode), while subtractive color results when an object reflects one color while absorbing all the others.

The students made a brief foray into genetics when they learned that women have a much lower chance of being color blind, in part because they are protected from the recessive trait by their second 'X' chromosome.

The classes taught at Springhouse are similar to the lessons that the SPIE students teach each summer at OPTO Camp, a week-long short course for middle-school students that is offered at Northampton Community College and at Lehigh by the university’s Center for Optical Technologies.

Dew Hongpinyo said the SPIE students hoped their visit to Springhouse would stimulate the sixth-graders to take a greater interest in science.

“When I was a kid,” she said, “I remember scientists coming to our school. I enjoyed seeing the cool demonstrations they put on. Now the situation is reversed. I hope the effort we put into these demonstrations will inspire the kids to do their own experiments.”

Those efforts appear to be paying off. For one of the more popular demos at Springhouse, Ding constructed two circuits on two breadboards. A transmitter circuit converted the electric signal from a CD player to an optical signal (via a light-emitting diode). A receiver circuit detected the optical signal and converted it to an electrical signal and then to an audio signal playing music.

“Many of the kids said they wanted to do this experiment by themselves,” said Hongpinyo, “and they asked me where they could buy a breadboard.”

--Kurt Pfitzer

Posted on Thursday, November 20, 2008

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