Saturday, December 9, 2023


EXPLODING rocks! Why you should NEVER put wet rocks in a campfire

By Cheri Sicard
Holy exploding rocks, Batman! The video below could literally save a life or at minimum a whole lot of pain. The Backyard Scientist shows you why.

The video has two parts. He tests the theory that molten aluminum in concrete can make it explode. OK, interesting enough. But more importantly for us campers and RVers is the danger that can happen when you have rocks, and more specifically wet rocks, in a campfire. That is also put to the test.

Our host heard, back when he was in the Boy Scouts, that putting wet rocks in a campfire can make them explode like grenades. Not content to take others’ words for it, he was determined to put it to the test. And he tests it with a bunch of different types of rocks such as granite, jade, slate, some river rocks, and a block of rocks with cement.

The first test involved only rocks that were dry.

Once he gathered the rocks, he set them all on fire and moved away. It took about eight minutes before he saw the first bit of action. Yes, the dry rocks did split and explode. But they weren’t quite grenade-like.

He then repeated the experiment with rocks that had been soaked in water. The theory being that the heating water puts extra pressure on the rocks, causing them to explode.

It only took a couple of minutes before the wet rocks started exploding and flinging shrapnel as far as 20 feet away.

Inexplicably, the host concluded it wasn’t that big a deal, and you would be safe even if you did put wet rocks in your campfire. I beg to differ. If you got hit in the wrong place with a flying bit of fiery rock, it could cause some serious injuries. Not to mention flying embers could accidentally start another fire.

To my mind, it simply is not worth the risk and I will be keeping rocks OUT of my campfires, with the possible exception of granite, which does not absorb water. At least according to the Backyard Scientist.

He concludes the video by setting the previously mentioned concrete on fire and it does indeed explode, but it turns out water is the culprit here too. Conclusion? Water and campfires don’t mix, unless you are dousing the fire.




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Steven Fry (@guest_212090)
1 year ago

Granite, and some other igneous rocks should be ok to put in a fire when wet or dry. Diorite, Basalt, Gabro, Andesite, and Ryolite; are just five other examples of rocks that are reasonably safe to put in fires weather wet or dry. Regarding any sedimentary rocks and a lot of metamorphic rocks, I would abstain from putting any of those in a fire, due to the risk of a catastrophic incident resulting from water trapped inside of those rocks.

Tim Bear (@guest_212088)
1 year ago

Native peoples have known this about damp rocks for, literally, centuries! Tribes that do
sweat lodge ceremony do feel that double-fist size river rocks are just the right size, but they ALSO know to find rocks that have been left high and dry for months if not years – by stream beds changing course, by finding former stream beds now dry due to global warming, etc

Rosalie Magistro (@guest_212057)
1 year ago

As a camphost this is so infuriating, I get so tired of taking rock out of the firepits.
If you are that cold that you’re trying to generate more heat,go in you RV !
And take the rock out before you leave .

STEVE (@guest_212054)
1 year ago

Even ‘dry’ rocks can have moisture trapped inside them.

Tom Gutzke (@guest_212028)
1 year ago

I wouldn’t sit anywhere near a fire with damp rocks, etc. Pieces of hot rocks, metal, etc. going 25 feet! If it hits you there will be an instant 3rd degree burn. If its hot enough it will go right through the skin!

RV Staff
1 year ago
Reply to  Tom Gutzke

Not to mention possibly taking out an eye, no matter the temperature of the piece of rock/shrapnel. Have a great day, Tom. 😀 –Diane

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