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Activity (Hands-On)Grades 6 - 8

Capillary Action in Sand

A photograph shows the black slick of an oil spill on a residential cul-de-sac street, spilling over a concrete driveway and contained in a pool by a curved concrete curb. The crude oil spill came from a rupture in ExxonMobil’s Pegasus 850-mile IL-to-TX pipeline in Mayflower, AR, in 2013.Student teams design experiments to determine the best sand type to use to clean up an oil spill.

As part of a (hypothetical) challenge to help a city find the most affordable and environmentally friendly way to clean up an oil spill, students design and conduct controlled experiments to quantify capillary action in sand. Like engineers and entrepreneurs, student teams use affordable materials to design and construct models to measure the rate of capillary action in four types of sand: coarse, medium, fine and mixed. After observing and learning from a teacher-conducted capillary tube demonstration, teams are given a selection of possible materials and a budget to work within as they design their own experimental setups. After the construction of their designs, they take measurements to quantify the rate of capillary action, create graphs to analyze the data, and make concluding recommendations. Groups compare data and discuss as a class the pros and cons of their designs. Pre- and post-evaluations and two worksheets are provided.

The study of capillary action in soil provides essential information to civil and geotechnical engineers. For example, understanding the soil properties in a given area enables engineers to specify materials and locations for construction projects to prevent any potential water damage. Geotechnical engineers extract crude oil using the process of capillary action. This activity provides an opportunity for students to think like engineers as they design and create models to analyze the upward movement of water in different mediums. Like real engineers, student teams are given budget limitations and must select the best affordable materials to solve a real-world problem and assess the performance of their designs to deliver solid recommendations.

After this activity, students should be able to:

  • Explain and illustrate the process of capillary action on the particle level.
  • Design a controlled experiment to quantify capillary action.
  • Design and construct a model that shows capillary action in soil.

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