Monday, July 21, 2008

Help With Chemistry

About a week ago we popped a rock into some vinegar. Today, this is what we have:

That's a horrible picture but my cheap little digital camera isn't so good with close ups. Anyways, the rock has now grown crystals. Crystals also line the 'high vinegar' line of the bowl.

The rock is from a Popcorn Rock kit we bought at a museum. the packaging says the rock is argonite but has no information on the process of the crystal growth. Some Internet searches have turned up little.

Anyone familiar with this and have a good explanation or link I could use with the kids?


molytail said...

I was here thinking "wow, they put a rock in vinegar and it did THAT??" ...until i googled "popcorn rock" and discovered it's a special kind of rock LOL ....

There's some info on crystals here:

if there's anything useful in that..

and here's someone's photo journal of their own popcorn rock growing..(well, they sell it)

Not sure if either of those are the sorts of things you're looking for...

molytail said...

K, that crystal link cut off.. it should end with /Growing_Crystals.htm

Ruth in NC said...

Here is a time-lapse YouTube video.

One of the comments says it is aragonite, a form of calcium carbonate.

I would guess that the vinegar dissolved the calcium carbonate from the "rock" and then it precipitated in a crystal form.

Looks like fun.

Ruth in NC

Dawn said...

Awesome! thanks for all the help! I wasn't getting much from my Googling (something I'm usually pretty good at) so I appreciate this.