A REPORT: What can we hear inside the box of -200°C?

I was fortunate enough to have the opportunity in our laboratory to record liquid nitrogen. We use it to disrupt plant tissues, making it easier to get better concentrations of DNA when we attempt extractions. I have used three microphones to capture this sound. The shotgun microphone was picking up the ambience of the sizzles when poured nitrogen made contact with plastic sample vials. Contact microphone was attached to the outside of the styrofoam box. However, the results were not fascinating. What did produce exciting results was putting another, relatively cheap piezo microphone directly into the box full of liquid nitrogen which resulted in cracking and popping for 40 minutes without problems. The microphone still works! When the microphone was taken out, it produced a fantastic “cooling off” sound which you can listen to at the far end of this recording—looking forward to exploring all of the 40min when time allows.