Absent-Minded Professors and Oscillating Circuits

I realize that I have never told you about my project. It has to do with superconductivity. The idea is to make a kind of circuit (Tunnel Diode Oscillator) which is extremely sensitive to changes, such as adding a magnetic field or dropping some atoms on it, etc. Once you have this, you put it into liquid helium and decrease the pressure to get a part of the circuit called the "meander line" to superconducting temperature. Once it superconducts, you have a very nice sine wave on the oscilloscope. Now, with a highly sensitive sine wave, we can do things to the meander line and its reactions will show up as variations on the sine wave. Apparently, this was something that the professor was working on in the 1980s but nobody has done anything with it since 1991 or so, meaning that I will be working on an unfinished old project. The effects of dropping ferromagnetic iron on the meander line has already been tested; I am going to do other things like shine electromagnetic radiation (light and its cousins) on it. It is actually rather exciting.

Yesterday, we built a part of the circuit to be connected to the one that hadn't been used since 1991. The problem was that neither of us knew that when soldering, you have to use solder. At first, I guess there was already some lead on the soldering gun, or on the wires, so we thought that the lead came from inside of the gun. After all, the word "gun" implies that it has ammunition. Who ever heard of a gun that required holding a bullet in front of it to be shot by the explosion? So we were mystified as to why nothing was coming out of the soldering gun, which was just making the wires hot and melting off the coating of the battery, when suddenly I noticed that a spool of wire said "solder" on it. Well, at that point we just started laughing.

Later, we had finished the circuit and built a copper coil, and put the apparatus all together with the professor. But something wasn't working right. So the professor started testing the resistance at different points on the circuit, muttering that something wasn't right, with us just standing, watching him. At one point, he asked us to get some liquid nitrogen for him, which we did, and brought it in. Another time he needed an oscilloscope. He put the device into the liquid nitrogen, which started bubbling vigorously upon the thermal contact, and plugged it into the oscilloscope. Still, it wasn't working. More testing of resistance. The problem was that it was getting late, and I had a family waiting for me to return for dinner. And the time it takes to walk to the subway station plus the traveling time, factoring in a bit of waiting for trains, can be as much as an hour. So I really had to do something about this. Around 5:40 my parents called me, and I told them that I was busy in the lab, and please, would they not call again. When it was closer to 6:40, I decided that I had to call them, because they would not like to wait indefinitely for me before cooking dinner. I did not know what to do. After that, I decided to tell the professor that my parents were waiting for me for dinner, at which point he said that I could go. I don't think he realized how late it was before that, because he was so caught up in trying to figure out what was wrong.

-Philip