These easy science experiments look at the difference between pumice and obsidian. Even though pumice and obsidian look very different they are made from the same igneous rock material. They are also both glassy rocks.
Pumice is a froth of igneous rocks that has so many gas bubbles it can float. There are reports that after the eruption of Krakatoa that some pumice formed rafts and floated for over 20 years before they sank. Approximately 90% of the rock will be gas bubble holes making it very light.
Obsidian is a volcanic glass that is between 70% and 75% quartz. It forms lava flows that ooze out of the ground. Even though there are large lava flows of this rock the lava does not crystallize. Some scientists believe it is because of its low moisture content that is about 1%.
Most obsidian is black and resembles basalt. It forms mainly from rhyolite a lava rich in quartz. Rhyolite is a light colored lava. The dark color of obsidian is due to impurities in the rock. In this science experiment you will use egg whites to see the relationship between obsidian and pumice.
Volcano Science Experiment, Cinder Cones Have you ever wondered how volcanoes get their shape? Find out about cinder cones in this fun activity.
Gravity Experiments, Balancing Acts Learn how to balance a potato, fork and pencil on the edge of a table.
Elementary Science Experiment, Earthquake Waves Create your own wave box that makes paper clips jump when earthquake waves pass through them.
Gravity Experiment, Topsy Turvy Plants Have fun growing tomatoes upside down in this fun experiment.
Elementary Science Experiments, Bird Feeders Study the feeding habits of wild birds in your back yard or porch area in this interesting experiment.
Easy Science Experiments, Pumice & Obsidian Find out the difference between pumice and obsidian and why one will float and the other will sink like a rock in these easy science experiments.
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