Photo of electronics on a circuit board within a clear plastic box.

Each student in this class builds and tests their own Geiger counter. (Photo courtesy of Mark Chilenski.)

By Joe Pickett, OCW Publication Director

You have four highly radioactive cookies, each emitting a different kind of radiation. You must

  1. Put one in your pocket
  2. Hold one in your hand
  3. Eat one
  4. Give one to a “friend”

What do you do?

Such is the challenge that begins 22.S902 Do-It-Yourself Geiger Counters, a course taught in MIT’s January 2015 IAP period by Professor Mike Short and Teaching Assistants Mark Chilenski and Matthew D’Asaro.  (You can read about the teaching assistants here.)

The goal of the course is just as the title states: building a functioning Geiger counter. And en route: learning about radioactivity, how to identify its different kinds, how to shield against them, how to calculate uncertainty, how to solder, assemble, test, and debug circuits, and lots more! All in five days!

Professor Short is a champion of active learning, and he explains why in Developing and Teaching Hands-on Courses, part of the Instructor Insights section of the course site for 22.S902 on OCW. As he sees it, the initial time investment is considerable, but the payoff is exponential:

“Whenever I put in the extra effort to make a hands-on course, the work I get back from students is better. It’s quicker to grade. It’s also more fun to teach hands-on courses because the students get what’s going on instead of just sitting silently through class. If you can teach the same content in a better way, then why wouldn’t you put in the extra work to do it?”

One of the challenges of active learning is getting students to overcome their fear of failure, and doing that, Professor Short insists, requires that the instructor earn students’ trust. Cheerleading also helps. He says repeatedly to the students:

“This is the class in which I want to see things exploding. This is where I want to see you do the high-voltage dance. This is where I want everything to go wrong, because you can’t get it to go right unless you see what goes wrong. This is a safe place where you can screw up.”

The course site includes instructions on how to build a Geiger counter (written by Mark Chilenski) along with tips on how to obtain the necessary parts.

Students in the class used their Geiger counters in many different ways—determining how much radiation people are exposed to in a flight from Boston to Hong Kong, seeing just how radioactive are those famous graves in Salem, Massachusetts, identifying chunks of uranium lying around near old mine sites . . . The uses are endless!