Video
Pumice Experiment with Ranger Sara
Transcript
Hi Junior Rangers! My name is Ranger Sara and today we are going to conduct an experiment about pumice. Pumice is a volcanic rock that is formed during violent volcanic eruptions.
If you haven’t seen pumice before, it is unlike most rocks. Most rocks, like this piece of granite, are heavy and dense, and sink when dropped into water.
Let’s see what happens when pumice is dropped into water.
It floats! Pumice is a rock that floats. But, how can a rock float?
Imagine shaking up a bottle of soda pop. Inside the bottle, gases such as carbon dioxide are dissolved into the liquid from pressure. Let’s see what happens when we take the cap off and relieve that pressure. Gases explode out of the bottle bottle!
This is similar to what happens to magma during a volcanic eruption that forms pumice. Pumice is filled with tiny air pockets called vesicles. These vesicles are evidence of gas that has exploded through magma.
Magma, which is now lava, then freezes around the vesicles.
Now Junior Rangers, I need you to follow the instructions in your junior ranger book and write down the observations you saw about pumice.
National parks, like Katmai, rock because of these rocks! And, pumice is one of the coolest rocks around.
Description
If you can’t go to Brooks Camp to experiment with pumice, then watch this video with Ranger Sara Wolman to complete the activity on page 11.
Duration
1 minute, 31 seconds
Credit
NPS
Date Created
02/02/2016
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