Tuesday, October 23, 2012

Three different Kinds of Volcanoes

For this activity you'll be creating explosions due to pressure build up because of gas released from the chemical reaction between baking soda and vinegar.  I've always used film canisters (they just work so well with so little).  As film canisters are harder to get these days (I saved all I could get when people started switching to digital), I'd suggest the smallest kind of snap on lid you can find instead.  Any containers should work so long as the lids are snap top only and not screw on or use any sort of latching mechanism.  I'd also suggest sticking with plastic (just to be on the safe side).  The bigger the container the more Vinegar and Baking soda you will need.

Start by making a shield cone type of eruption with plastic wrap rubber banded over your canister.  Get everything ready with vinegar in the canister, the plastic wrap ready and an assistant with the rubber band stretched and nearly over the canister already.  Drop in a scoopful of baking soda, slap the saran wrap down and the rubber band around the rim (or if the container is small enough, just hold it in place).  I suggest the parent act as assistant and the child do the pouring in of the baking soda (you will probably be faster) or let your kids take turns in each role if you have older kids.

If all is sealed well, the wrap will form a dome as it stretches bending to the pressure.  Eventually a crack, slit or other release point will form and bubbles will "ooze" out of your volcano the way lava runs down the sides of a shield volcano.

For a composite or stratocone volcano, you'll need to poke a small hole in the lid.  Then operate the same way.  Have everything ready.  Vinegar in the canister, assistant ready with lid and then the scientist puts the baking soda in.  This volcano will erupt with a swoosh upward and then end with oozing, showing mild explosiveness along with the oozing similar to that of the shield volcano.

I'm sorry I don't have a photo of this happening in my third canister.  You'll have to be a much more talented (and quicker) photographer than I to get one - of course, as photography is not my skill set, you probably are.  The modeling of the cinder cone volcano is the most impressive which is why I made it last, although if you have only one container lid, you'll want to do this one second.  For the cindercone, pour in your vinegar, get ready, drop in the baking soda and slam the intact lid onto the canister.  Wait a few seconds and the lid will be bouncing off your ceiling and most of your vinegar bubbles will already be gone and you'll just have a mess on the counter, table (or sidewalk) where the canister was.  Be prepared to go looking for the lid and canister after this one.  Alice giggled her head off and said, "mom we have to do that one again!"

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