# Smoke Alarms: How Do They Work?

**URL:** <https://boards.straightdope.com/t/smoke-alarms-how-do-they-work/275409>\
**Category:** Factual Questions\
**Created:** [November 18, 2004, 3:21am UTC](https://boards.straightdope.com/t/smoke-alarms-how-do-they-work/275409 "2004-11-18T03:21:46Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [November 18, 2004, 3:21am UTC](https://boards.straightdope.com/t/smoke-alarms-how-do-they-work/275409/1 "2004-11-18T03:21:46Z")

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How exactly do smoke alarms work, and what is the smallest particle they can detect??? Along with this question, what keeps the smoke alarm silent when there is nothing there to detect? - Jinx

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**Author:** ![Reeder](https://avatars.discourse-cdn.com/v4/letter/r/c6cbf5/32.png) [@Reeder](https://boards.straightdope.com/u/Reeder)\
**Post date:** [November 18, 2004, 3:23am UTC](https://boards.straightdope.com/t/smoke-alarms-how-do-they-work/275409/2 "2004-11-18T03:23:50Z")

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> **[How Smoke Detectors Work](https://home.howstuffworks.com/home-improvement/household-safety/smoke.htm)**
>
> As the saying goes, "Where there's smoke, there's fire." Smoke detectors are amazing: They're pretty inexpensive, but they save thousands of lives each year. Learn all about nuclear and light-sensing smoke detectors.

Great site.

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [November 18, 2004, 4:11am UTC](https://boards.straightdope.com/t/smoke-alarms-how-do-they-work/275409/3 "2004-11-18T04:11:07Z")

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> [@Jinx](#):
>
> Along with this question, what keeps the smoke alarm silent when there is nothing there to detect? - Jinx

Um, what? Think about that question for a minute.

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**Author:** ![Reeder](https://avatars.discourse-cdn.com/v4/letter/r/c6cbf5/32.png) [@Reeder](https://boards.straightdope.com/u/Reeder)\
**Post date:** [November 18, 2004, 4:18am UTC](https://boards.straightdope.com/t/smoke-alarms-how-do-they-work/275409/4 "2004-11-18T04:18:29Z")

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> [@Q.E.D.](#):
>
> Um, what? Think about that question for a minute.

Cut the kid some slack.He’s just crammed pack full of questions.

He has no time to think.