Ancient Exploding Cannonballs

Planetes writes "There is a story on MSNBC about some surprise archaeology. Apparently, cannonballs from shipwrecks are "exploding" (more like heating up and cracking open) when they are exposed to air. At least one reacted so violently it reached several hundred degrees. Talk about a booby trap. I'd never have seen this one coming." Heat from oxidation (that's "rusting", if you haven't taken chemistry) has started many fires in cargo ships carrying iron.

Comments

Great Balls of Fire!!

[savage_panda]

This information is great to know if ever your stranded on a desert island with a coral reef around it, which has caused some shipwrecks of vintage warships with cannonballs. It would be a way to cook coconuts, a way to heat your hut at night, and start fires without matches, not to mention the other basic uses of a cannonball like lawn bowling and basketball.

Cross your legs

[hij]

The combination of oxygen and sea salt caused rapid oxidation resulting in the balls? ?exploding? open and crumbling into bits.

This is why I don't like to pull them out into the open air.

Rust at work

[R2.0]

There's a road in the northwest that was closed because it was effecively on fire. The state specified ground-up tires be used in the fill under the road in an eco-friendly gesture. Groundwater started the steel belts in the fill rusting, the heat started the rubber burning, and now smoke is coming out of the ground.

Like in KSR's Mars trilogy

[MagikSlinger]

One of the theories I've always heard is that if Martian soil was ever exposed to signficant water (i.e., enough to thoroughly wet it), the soil of Mars could start reacting violently because it's mostly iron that hasn't had the advantage of water to ensure the iron is fully rusted.

KSR has some fun with this when he described a flood released onto pristine Martian soil. Snap, crackle, pop, kids.