“Who wants to see if they are a Zombie?” asks Professor Carl Franck, causing all twelve Girl Scouts in the room to look up from their work and stare in bewilderment. “Let’s go outside and see if you are really alive by using a TV satellite dish to measure your body heat!” Still doubtful, a handful of girls get out of their seats and walk excitedly towards the door, following Professor Franck outside. The dish, which picks up microwave frequencies around 12GHz, will be used to measure the amount of thermal radiation being emitted from a girl standing in front of it against the cold sky. This amounts to a microwave thermometer test that allow the girls to see if their bodies radiate heat in the way that a Zombie’s cannot. Happily, all the scouts who try pass this test and the program moves along without fear except that they now know that at least some of them are a source of microwave radiation.
This was just one of the several engaging and educative activities taking place at the eXploration station on a crisp Saturday in early November where eight Cornell University students in physics and engineering worked alongside Junior and Cadette Girl Scouts from the Trumansburg service unit to learn about radio waves and assemble their own crystal radio. The graduate and undergraduate student staff had spent the prior Saturday building their own radios and learning how to work with lead-free solder, wind the tuning coil, space and set wire taps, and assemble the circuitry according to the provided schematic. Their ideas for improvements in technique really helped to make for a better scouting experience. The Cornell students also helped suspend a long antenna, stretching from the inside of the station out into nearby trees, extending about 25 feet in either direction to pick up amateur (“ham”) radio signals from across the northeastern America “I started getting interested in ham radios when I was in high school” stated Chris Pierce, a physics graduate student, after signing off from a conversation (that included a courageous scout at the microphone) with another operator in Massachusetts, “and I got certified as a ham radio operator as an undergraduate. I’ve stuck with it ever since.”
The girl scouts, who were working on earning their Radio and Wireless Technology patches, spent their Saturday at Wilson Lab building their radios under the guidance and tutelage of the Cornell students. The students, ever so patient with the scouts, shared their insight and advice on how to interpret the schematic diagrams. Robin Bjorkquist, graduate student in physics, advised two scouts, ages 9 and 10, and spoke at a level they could understand, “This circuit diagram is going to tell us where we need to put pieces and how we need to connect these pieces together. Your job is to figure out what piece connects to where — like, what goes next to this pin.” Athena, a Junior scout, respond, “Like this?” and places the diode, or crystal, next to the pin. “Yes, exactly like that!” exclaims Robin. Kimberly Chen shared some of her own strategies with the Cadettes (ages 11-13) that she was advising. “What I like to do is use my finger and trace the diagram so that I can follow the path of the wire” says Kimberly, placing her finger on the schematic in front of them and following the drawn wire. “Oh, that makes sense” states Ella as she attaches the wires from the earbud to the same pegs on which both ends of a resistor are soldered.
After hours of toiling away at winding, tapping, and soldering, Piper, a first-year Junior scout exclaimed “This is not easy! It is fun. Except for the scary part of burning my fingers, it is really fun!” The girl scouts tested their crystal radios, hooking up the tuning coil of their radios to another antenna wire stretched outside. Inside their coils high frequency currents build up when it is tuned by the scouts to match the incoming radio wave’s frequency. “It works!” exclaims Mena. “I can hear someone talking about Cornell. We can only get one channel in. It’s football. But at least it’s Cornell football.” We hope these ambitious young scouts will come back for some more science and engineering activities under the guidance of student mentors, Cornell student mentors.
Many thanks to Cornell students:
Robin Bjorkquist
Kimberly Chen
Jen Chu
Saaj Chattopadhyay
Berit Goodge
Michelle Kelley
Betul Pamuk
Chris Pierce