When Nature Strikes: Volcanoes and Viscosity

Students will investigate the viscosity of various liquids by blowing bubbles and by determining the velocity of a marble falling through the liquid. They will then compare the viscosity of those liquids to the viscosity of different kinds of magma and investigate the connection between magma viscosity and types of volcanic eruptions. Materials:

Materials for Part 1

5 250 ml beakers, jars, or glasses

5 straws

Tray or paper to contain spilled liquid

5 liquids such as water, pancake syrup, corn syrup, vegetable oil, shampoo


Materials for Part 2

5 large graduated cylinders or tall containers filled with the 5 liquids used in part 1

15 dark colored marbles



Water soluble marker


written by Wendy Van Norden
Grade level:
Preparation 10 minutes

Activity class time: 50 minutes

Discussion and Review: 20 minutes

Student Learning Outcomes:
  • Students will be able to explain the concept of 'viscosity' of a liquid.
  • Students will see the effect of the viscosity of a fluid upon the flow of gas through that fluid.
  • Students will be able to explain why basaltic magma is less viscous than rhyolitic magma.
  • Students will be able to measure the movement of a marble through a fluid and calculate the velocity of the marble based upon the measurements.
  • Students be able to make connections between the viscosity of fluids that they observed and the behavior of rhyolitic, andesitic and basaltic magmas.
  • Students will be able to determine the effect of viscosity of magma upon the kind of volcanic eruption and the shape of a volcano.
Lesson format:
Laboratory Experiment

Standards Addressed:

This lesson assists learners in developing proficiency in NGSS Performance Expectation MS-ESS3-2 (Analyze and interpret data on natural hazards to forecast future catastrophic events and inform the development of technologies to mitigate their effects.)

This lesson assists learners in developing proficiency in NGSS Core Idea MS-ESS2-2 (Construct an explanation based on evidence for how geoscience processes have changed Earth's surface at varying time and spatial scales)

This lesson assists learners in developing proficiency in NGSS Core Idea PS1.A (structure and properties of matter)

This lesson assists learners in developing proficiency in NGSS - Crosscutting Concepts of Scale, Proportion, and Quantity

This lesson assists learners in developing proficiency in NGSS Eight Practices for K-12 Classrooms (Planning and carrying out investigations, analyzing and interpreting data, using Mathematics and computational thinking )


Start learning about volcanoes and the scientists who research them by having class watch the When Nature Strikes: Volcanoes video.

All liquids should be light enough so that a marble can be seen within them. Recommended liquids are water, corn syrup, vegetable oils, pancake syrup, glycerin, shampoo or liquid soap.

While a 500 ml or a 1,000 ml graduated cylinder is ideal, it is not necessary to use a graduated cylinder in part 2 as long as the container is tall enough to allow for about 5 cm drop between the top line and the bottom line. It will be difficult to get an accurate timing with water and oil, especially with a short container, but students can definitely see that there is a difference between the times.

Encourage students to offer explanations as to why silica adds to a magma's viscosity. Encourage students to offer explanations as to why a more viscous magma erupts less frequently and more violently than magma that is less viscous. You may even what to ask students to research different volcanoes that they have heard of and see if their eruption pattern and lava composition matches this activity.


Student worksheets can be easily graded using a rubric appropriate to the age group.


Goggles should be employed to keep any soaps from student eyes.


Clean-up is messy, so to minimize the number of clean-ups, it is possible to use the same cylinder repeatedly, and simply raise the level of the start and finish lines once there is a layer of marbles at the bottom. All liquids can be returned to their original containers and reused.


For older students it is possible to calculate the viscosity, using the following worksheet


Background information can be found on the student worksheets.



Last modified April 30, 2016 by Jennifer Bergman.

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