# What differentiates a bottle rocket from a firecracker? **URL:** \ **Category:** Factual Questions\ **Created:** [August 22, 2012, 6:59pm UTC](https://boards.straightdope.com/t/what-differentiates-a-bottle-rocket-from-a-firecracker/632295 "2012-08-22T18:59:09Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [August 22, 2012, 6:59pm UTC](https://boards.straightdope.com/t/what-differentiates-a-bottle-rocket-from-a-firecracker/632295/1 "2012-08-22T18:59:09Z")
Aside from the stabilizing tail of a [bottle rocket](http://www.google.com/imgres?q=bottle+rocket&start=191&hl=en&biw=1344&bih=759&addh=36&tbm=isch&tbnid=zXkIfwjOgX9NtM:&imgrefurl=http://www.hollywoodchicago.com/news/6225/blu-ray-review-criterion-launches-blu-ray-division-with-90s-independent-hits&docid=co2ZBz6Hh8tTxM&imgurl=http://www.hollywoodchicago.com/sites/default/files/Bottle%252520Rocket_image3.jpg&w=640&h=436&ei=kiY1UJO0Foam9gS-rYCgBw&zoom=1&iact=hc&vpx=951&vpy=18&dur=140&hovh=185&hovw=272&tx=132&ty=106&sig=101716889683591476927&page=7&tbnh=138&tbnw=184&ndsp=35&ved=1t:429,r:12,s:191,i:151), they physically don’t appear to differ much from a [firecracker](http://www.google.com/imgres?q=black+cat+firecracker&hl=en&biw=1344&bih=759&tbm=isch&tbnid=zo5iS0M_XzOxyM:&imgrefurl=http://artofmanliness.com/2008/07/01/the-ultimate-guide-to-best-fireworks/&docid=yx7VCjc-W79zlM&imgurl=http://content.artofmanliness.com/uploads/2008/07/blackcat1.jpg&w=450&h=317&ei=vyk1UK6nN4nk8gTx7ICwDA&zoom=1&iact=hc&vpx=552&vpy=59&dur=1000&hovh=188&hovw=268&tx=117&ty=108&sig=101716889683591476927&page=1&tbnh=154&tbnw=185&start=0&ndsp=18&ved=1t:429,r:8,s:0,i:124). They’re about the same size and appear to be constructed similarly, a short line of gunpowder wrapped in a cylindrical roll of paper. Yet they behave quite differently; one immediately explodes in place and the other shoots off into space due to a progressive ignition. So what exactly is it that causes these two disparate reactions? Is it a different type of gunpowder? Is one vessel completely confined while the other is provided an escape point for the gasses? Is it the tightness of the wrap? I’ve wondered since I was a kid and no better place to ask… Thanks in advance. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [August 22, 2012, 7:14pm UTC](https://boards.straightdope.com/t/what-differentiates-a-bottle-rocket-from-a-firecracker/632295/2 "2012-08-22T19:14:51Z")
[QUOTE=lieu;15411987 Is one vessel completely confined while the other is provided an escape point for the gasses? [/QUOTE] Bing Bing Bing We have a winner! The hot gases have no way to expand in a firecracker, except by exploding the paper wrapper. In a bottlerocket (at least the propulsion stage), they gases can shoot out the open bottom. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [August 22, 2012, 7:16pm UTC](https://boards.straightdope.com/t/what-differentiates-a-bottle-rocket-from-a-firecracker/632295/3 "2012-08-22T19:16:11Z")
And, the bottle rocket will usually include a secondary chamber with too small an entry for the gases to escape, so they explode once they’re up there. ---
**Author:** ![Arkcon](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@Arkcon](https://boards.straightdope.com/u/Arkcon)\ **Post date:** [August 22, 2012, 7:43pm UTC](https://boards.straightdope.com/t/what-differentiates-a-bottle-rocket-from-a-firecracker/632295/4 "2012-08-22T19:43:32Z")
Similar size and shape of charge, maybe, but the composition of a bottle rocket is more forceful. As a kid, it was a fun thing to do to crack open a firecracker and ignite the compound in a pile to a quick flash. If you try that with a bottle rocket, the flash is more of a light bang, even though it is no longer contained. I was pretty surprised, and the guys warned me, people have singed their fingers that way. It was serious, but apparently, not serious enough to warm me before I did it. Pre-teen boys are like that. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [August 22, 2012, 7:51pm UTC](https://boards.straightdope.com/t/what-differentiates-a-bottle-rocket-from-a-firecracker/632295/5 "2012-08-22T19:51:46Z")
Doesn’t the gunpowder in a bottle rocket burn a little slower and cooler?