In bicycle design, a boom tube is an oversized frame tube, which typically replaces two of the three traditional tubes of a diamond frame. An example of a boom tube frame would be a Klein Mantra. Another use of the term is to describe the tube which connects the two bottom brackets of a tandem.
One day, while working at the shop, we accidentally created another definition for for the term.
We were working along, and one of the guys casually wondered, out loud, how big a 26" mountain bike inner tube would get if you inflated it outside of a tire. Always the (mad) scientist, I decided it was a worthy experiment. So, I went to the box of take-off tubes (many people swapped to Slime-filled tubes, or some such, when buying a bike), and pulled out a presta-valve tube.
I pushed the presta chuck of the air hose onto the tube, and squeezed the handle. As the tube inflated, we figured it would get pretty big, then split and deflate. And, it did get pretty big.
When it's diameter reached my height, I decided I didn't want to hold it. I took a toe-strap, and strapped the filler handle of the hose down, and stepped back. The tube continued to grow.
I think it must have been seven feet in diameter when it popped. And, it wasn't a simple "split and deflate" scenario. It sounded like a bomb went off, when the tube finally ruptured. Talcum powder, from inside the tube, billowed out and a haze hung in the air. Along with the ringing in our ears, the smoky haze added to the bomb-like effect.
All five us who were watching it, fully expecting it to blow, had jumped in surprise at the amount of noise it made. We heard some exclamations of surprise from the sales floor, through the door of the service area, and some nervous laughter.
About 30 seconds later, as we were all marveling at the results of our little experiment, Scott walked in, dabbing Coca Cola off of his shirt with a shop rag. He had been taking a sip of his Coke, in his office, when the tube exploded.
He wasn't watching the tube, waiting for the boom. Hence, he had jumped a bit more than we five had.
It was politely requested that we refrain from such behavior, after that moment in time.
In no uncertain terms, that is.