What's inside a fire alarm


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What’s inside a fire alarm?

Nothing but trouble, and that starts with T and that rhymes with P and that stands for PULL.


It’s called SIMPLEX, what did you expect?


They should make one like this: https://youtu.be/aqAUmgE3WyM


It is what is on the other side of the wall that is interesting…


When I was a lad, the common schoolyard knowledge was that the little hole at top center was a nozzle that would squirt messy ink all over you when you pulled a false alarm at school, so we never did so. Later, I bought a surplus one of these (the slide-down instead of pull-out variety), and installed it in my bathroom as the light switch. I lived in a party house, so it was a lot of fun at parties. It lasted five years!

I must point out that the little hole at top center is the set screw that holds the thing closed. No nozzle with messy ink to be found.


yes, where the hell is the blue ink squirter!? I have been deceived!


Actually, a spray of some degradable UV-reactive dye (maybe something that air-oxidizes away?) or some other taggant would be a good way to find who pulled the alarm if it was a false one.


I came to say exactly the same thing. How did urban legends like this spread to schools across the country before the internet?


I regret that I have but one like to give this comment!


The ink-squirter was a central plot point in Bruce Coville’s My Teacher Fried My Brain and I always assumed it had some basis in fact, but I can’t say I would have heard of it otherwise.

(There should be somewhere one can go and yank on different shapes of disconnected fire alarms to one’s heart’s content.)


Was it the same stuff that they put in the swimming pool?


For figuring out who peed in it?



the terrorism alarm seems to be much bigger ‘fun’ these days.



Back when I was in high school, I considered calling the cops and reporting a calorimeter bomb in the ground floor lab. (It was really there, that fairly massive pressure vessel of the bomb calorimeter.)

Later I confessed to my teacher and he said with a smirk that I should’ve done that.


All I have to say is that I’m also very disappointed.

A toggle switch…:confused:


Or just wait until someone outs the person. It is my experience that teenagers these days cannot keep secrets. I think it’s a mixture of social media and overwhelming trust. It’s kind of sweet.


When I was a lad, the teachers promulgated the same story, cheerfully lying to the little tykes to foster obedience and fear.


hey! toggle switches are totally fine!