# Special effects explosions

**URL:** <https://boards.straightdope.com/t/special-effects-explosions/299732>\
**Category:** Factual Questions\
**Created:** [April 17, 2005, 5:54am UTC](https://boards.straightdope.com/t/special-effects-explosions/299732 "2005-04-17T05:54:21Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![furt](https://avatars.discourse-cdn.com/v4/letter/f/439d5e/32.png) [@furt](https://boards.straightdope.com/u/furt)\
**Post date:** [April 17, 2005, 5:54am UTC](https://boards.straightdope.com/t/special-effects-explosions/299732/1 "2005-04-17T05:54:21Z")

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This just in: the movie **Windtalkers** really sucks.

It’s got a lot of explosions and I’ve noticed that several of them (a grenade and a BB 16 incher were two) have had what I call “sparklers:” bright-burning fragments trailed by white smoke that shoot out from the center explosion in a roughly symmetrical pattern. You see them all the time in lower-budget war flicks. I hope that makes sense; hopefully you know what I’m talking about.

“Boy,” says I. "Them’s some phony-looking special effects. "

“How the hell do you know? You’ve never seen a grenade go off.” I respond to myself.  
But someone on the SDMB has, and can explain what those things are and if they’re realistic or not.

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**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\
**Post date:** [April 17, 2005, 6:03am UTC](https://boards.straightdope.com/t/special-effects-explosions/299732/2 "2005-04-17T06:03:39Z")

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The news footage I’ve seen of grenade explosions tend to be dominated by clouds of dirt and smoke, with occasional flashes of flame. The white sparks you see in movie explosions are most likely caused by adding magnesium to the mix. Generally grenades don’t have that (some probably do, but certainly not all).

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**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\
**Post date:** [April 17, 2005, 12:46pm UTC](https://boards.straightdope.com/t/special-effects-explosions/299732/3 "2005-04-17T12:46:46Z")

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Generally speaking, if you throw a granade you _don’t_ see the explosion, behause you’re busy burying yourself behind cover. That’s why I’ve never actually seen any I’ve thrown myself explode. However, from watching from a safe distance, I can tell you that basically what happens is this:

1. A loud _THUMP_ - felt as much as heard.

2. A very brief, surprisingly small flash of red flame.

3. A tall pillar of black smoke.

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**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\
**Post date:** [April 17, 2005, 2:43pm UTC](https://boards.straightdope.com/t/special-effects-explosions/299732/4 "2005-04-17T14:43:21Z")

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Real high explosives are not exciting enough for movies. They expend all their energy in an extremly rapid time so all that travels out is a high pressure wave. Black powder and pyro assisted gasoline explosions are fun to watch but all the flame you see is considered wasted energy as it doesn’t add significantly to the pressure wave.