Strata and Shield Volcanoes - Viscosity Activity for Kids

Earth Science Unit Study

Week 28: We tested several liquids to determine which was the most viscous.

The lava in strata volcanoes is very sticky or viscous and over time can plug the opening where magma escapes from the Earth. Strata volcanoes like those of Krakatoa and Mt. Saint Helens are often very explosive and have violent eruptions. In contrast, the lava in shield volcanoes, like those in Hawaii, is runny and flows easily away from the vent.

How the Earth was Made - Krakatoa and Anak Krakatou tells the story of this explosive strata volcano. Located in Indonesia, in 1883, Krakatoa blew itself off the map. Today, its child, Anak Krakatou, grows over 12 feet per year.

Because the lava in Krakatoa was very sticky it formed a plug. Over time, new magma rising to the surface increased the pressure on the plug. Just as Krakatoa blew up in the past, one day in the future, a major eruption of Anak Krakatau is expected.

How the Earth was Made - Hawaii tells a very different story. The Hawaiian Islands were formed from a volcanic hot spot under a tectonic plate. As the plate drifts, the hot spot just punches a new hole where lava flows out. The hot spot annually produces millions of cubic yards of lava which enable the big island to increase in size by over one mile every year.

To demonstrate how lavas flow, but at different rates, we measured the viscosity of several liquids found commonly in the house.

Viscosity Activity for Kids

The viscosity of several liquids was compared by measuring the time required for the liquid to spread over the surface of a plate.

Honey, molasses, shampoo, dish soap, ketchup and milk were tested.

A small amount of the test substance was spooned or poured onto the plate.

The timer was stopped when the liquid quit moving.

All of the liquids were retested after heating them in hot water.

Results - A simple table was created and the times were recorded. Heating all the liquids made them less viscous. Honey was the most viscous liquid and milk was the least.

Jamari's Drum is a fun picture book to read in conjunction with any volcano activity. It tells the story of how Jamari restores order in his African village after the volcano erupts. Perfect for ages 4-10.

The House on the Volcano is a short chapter book to read along with a volcano unit study. Set on a Hawaiian Island, two children disagree over whether Madame Pele is responsible for the volcanic eruption, or whether there is a scientific explanation. Written in the 1960's a few parts would likely be rewritten today.

Mount St. Helens Volcano: Violent Eruption (American Disasters) is a non-fiction book that tells the story of the Mount St. Helens eruption. It gives us a glimpse into what people were doing, how they survived, and how the eruption effected the region. 



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