The most poignant moment of whole the affair was when the alarm sounded and the lights flashed, and everyone in my classroom laughed because they knew why.
We're in the midst of our unit on light. We talk about why we can't see a laser beam between the laser and the dot of light it puts on a distant wall. Then I modify the air in the room so we can see the beam. In the old days, physics teachers used chalk dust as a scattering agent. But chalkboards have been relegated to museums. There was a time when certain physics teachers used cigarette smoke. But smoking was long-ago banned from school sites.
What's a physics teacher to do? Several years ago, I came across "professional haze"/"fog in a can" in the Arbor Science catalog. It was a wee bit pricey, and you needed to use quite a bit of it to get the desired effect, but it worked. So for the past several years, that's how we turned my classroom into a laser light show. Eight bright, green laser beams sweeping through a darkened room with "visible air" is a memorable scene.
Unbeknownst to me, a recent fire safety review of the school resulted in some changes on campus. The sensitivity of the smoke detectors was apparently increased. Significantly.
So as soon as I started fogging the room with my professional haze, blammo: klaxons and flashing xenon strobes! School wide. The students broke out in laughter and I had to follow along before sending them to join the rest of the student body out for the fire drill.
I thought I might make it through my entire career without causing a fire drill. I was wrong. Back in 1986--before my 22nd birthday--I actually had an unplanned fire in my classroom, but no detector detected and no alarm sounded. I was about three weeks into the profession (new school, new town, new state, first job) when a lighting ballast burst into flames. I knew where my nearest fire alarm was and I quickly pulled it. Nothing. The fire burned itself out, but it was startling to my very young self.
So many years later, when I set the alarm off unintentionally, all I could do was laugh.