For most people, the gray satellite television dishes that cling to roofs and buildings are mundane fixtures. For Andover High School physics teacher Michael Doherty — and soon for his students, too — they are much more.
Doherty spent eight weeks this summer writing curriculum on how a Direct TV-style satellite dish — known scientifically as a Very Small Radio Telescope, or VSRT — can be used in high school classrooms to conduct experiments and learn about radio waves. He was one of three high school science teachers chosen for the summer program, hosted at Massachusetts Institute of Technology's Haystack Observatory in Westford and funded by the National Science Foundation.
"It was quite cathartic to develop curriculum, instead of implement it," said Doherty, who has taught physics, chemistry and electronics at Andover High for 13 years. "It was a very rewarding experience, I'd highly recommend it to any teacher."
Doherty will use the curriculum he developed in his classes at AHS, he said. As part of the workshop, he was given a Direct TV receiver to use for experiments. Also, Doherty will be training the freshmen physical science teachers how to use the receiver for experiments that fit into their curriculum.
The experiments with the television dish will be totally hands-on, he said, conducted in one of the school's science labs.
"This allows kids to learn about radio waves, which you don't do other than in a pencil-and-paper kind of way," Doherty said.
While waves in the electromagnetic spectrum range from standard AM and FM radio signals to microwaves, a satellite-TV dish is designed to receive only waves that are 12 gigahertz, Doherty said.
Conveniently, florescent lights also give off 12 gigahertz radio waves, he said. That, coupled with the fact that a television receiver can be purchased for less than $100, makes a perfect setup for classroom experiments, Doherty said.
In one experiment, students will move a florescent lightbulb closer and farther away from the VSRT, and then calculate how much the strengths decrease or increase as they move the bulb — learning about the inverse square relationship, he said.
Doherty is working on his doctorate in science education, taking classes at the University of Massachusetts Lowell.
This summer, he spent eight weeks working with Mindy Lekberg, a Chelmsford High School teacher and Stephen Minnigh from Nashua South (N.H.) High School, developing curriculum and testing experiments with the VSRT. The lesson plans they created are available to any teacher online, at www.haystack.mit.edu.
"I've never met a physics teacher that I didn't enjoy working with," said Doherty, breaking into a smile. "They're good folks."