Hands-on Activity: What's Down There?

Contributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

A pumpjack used in an oil well in Texas.
What's down an oil well?
Copyright © Microsoft Corporation 1983-2001.


During this activity, students learn how oil is formed and where in the Earth we find it. Students take a core sample to look for oil in a model of the Earth. They analyze their sample and make an informed decision as to whether or not they should "drill for oil" in a specific location.
This engineering curriculum meets Next Generation Science Standards (NGSS).

Engineering Connection

One tool engineers use to find oil is core drilling. Huge drills extract cylinders of rock or sediment from below the Earth's surface. Petroleum engineers use microscopes to study these cores in a laboratory, looking for the presence of fossil fuels. They use their understanding of the composition of the layers of the Earth to analyze the (potential) reservoir rock properties (porosity, permeability, saturations, compressibility, etc.) to make informed decisions about where to drill, and minimize the number of costly wells they must drill to obtain oil.

Learning Objectives

After this activity, students should be able to:

  • Describe the layers under the Earth's surface.
  • Understand how fossil fuels are formed and where they come from.
  • Understand the important role that engineers have in finding and extracting oil.

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Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

  • Obtain and combine information to describe that energy and fuels are derived from natural resources and their uses affect the environment. (Grade 4) Details... View more aligned curriculum... Do you agree with this alignment?
  • Investigate and identify two or more ways that Earth's materials can be broken down and/or combined in different ways such as minerals into rocks, rock cycle, formation of soil, and sand (Grade 3) Details... View more aligned curriculum... Do you agree with this alignment?
  • Describe the energy transformation that takes place in electrical circuits where light, heat, sound, and magnetic effects are produced (Grade 4) Details... View more aligned curriculum... Do you agree with this alignment?
  • Identify and describe the variety of energy sources (Grade 4) Details... View more aligned curriculum... Do you agree with this alignment?
Suggest an alignment not listed above

Materials List

Each group should have:

  • 6 different colors of Play-Doh® or modeling clay (three different colors for three different layers of the Earth; light brown for cap rock; black or dark brown to represent oil and dark blue or another color for sides).
  • 3 straws
  • Scissors (groups may share)


Currently, oil provides much of our nation's energy source. Although, engineers and geologists are trying to find new ways of harnessing energy, the United States still depends on oil and coal to power our cars and generate heat and light. These fossil fuels are combusted in large power plants, with emissions of pollutants being released into the air, land, and water. Some of these emissions include carbon dioxide (CO2), particulate matter (PM), and heavy metals, including lead (Pb) and mercury (Hg). Furthermore, gasoline is combusted in the motors of cars, and these emissions are also released into the atmosphere (eventually settling onto water or soil, or possibly remaining in parts of the atmosphere forever). Extraction of the fossil fuels themselves is also harmful to the environment, promoting underground rock fracturing and possibly contamination of groundwater that may be used for drinking water. Furthermore, the gases released from drilling are very potent greenhouse gases and promote global climate change (warming of the earth's atmosphere).

Oil is only found in sedimentary rocks. Organic matter (from dead marine organisms) was deposited millions of years ago and than trapped under an impermeable layer of hard rock, or sedimentary layers. After many years, and after an increase sedimentary layers resulted in intense pressure and heat, the microorganisms that were trapped under these layers formed fossil fuels — of which oil is one form. When the layers of rock faulted (or folded) from tectonic plate movement or earthquakes, wells or reservoirs of oil were created (see Figure 1). It is these reservoirs that engineers tap into to extract oil for use by the U.S., as well as other countries.

An illustration of large oil deposits, found where rocks have folded within the Earth's layers.  Shown are brown, white and gray layers   with an oil deposit shown in black.
Figure 1. An illustration of large oil deposits, found where rocks have folded beneath the Earth.
Copyright © http://seeps.wr.usgs.gov

We cannot see oil under the ground, so how do we find it? One method used to find oil is core drilling, in which long cylinders of rock or sediment, called cores, are removed from deep below the Earth's surface. Once these cores are brought up to the surface, they are analyzed by engineers and geologists to find the presence of oil. Clearly, the Earth's surface cannot be poked with holes until drillers get lucky and hit oil; so instead geologists and engineers use their knowledge about the Earth's layers to determine the best, most logical place to drill for oil. Can you name the layers of the earth? (Answer: inner core, outer core, mantle, crust)

In this activity, we will take core samples from a model of the Earth and look for oil (represented by black or brown clay). Some students will strike oil and some may not.


Before the Activity

  • Purchase/gather all necessary supplies.
  • Print out/copy Core Sample Worksheets, one per student.
  • If time permits, make an Earth sample for each group. (An alternate method would be to have different groups make samples and then put them all into a grocery bag and pass them back out randomly.)
  • Take equal quarter-size balls of each color of the clay and flatten each color to represent a single layer of the Earth.
  • Stack three of the layers on top of each other.
  • For half of the samples put an "oil" layer (remember to use black or brown clay) somewhere between the layers. (Note: Make sure all samples are the same height.)
  • Cap all the samples with light brown clay on top (see Figure 2) and dark blue clay on the sides (this hides the colors of the interior).

The above picture is four circular layers of clay stacked on top of one another.
Figure 2. Layers of Earth model (with the top cap layer, but without clay around the outside).
Copyright © Jessica Todd, University of Colorado at Boulder, 2004.

With the Students

  1. If you prepared them beforehand, pass out an earth sample to each group. Otherwise, have the groups prepare the earth samples as instructed in "Before the Activity" of the Procedures section. Then put all the samples into a grocery bag and pass them back out randomly.
  2. Tell the students to imagine that these small samples are big fields in Texas or the Middle East.
  3. Review the layers of the earth with the students by labeling the layers of the clay model on the chalkboard (inner core, outer core, mantle, crust; see Figure 3).

A diagram showing the different layers of the Earth and the miles of thickness for each layer. The inner core is in white, the outer core is yellow, the mantle is red, the continental plate is brown and the oceanic plate is dark blue.
Figure 3. Layers of the Earth
Copyright © http://volcano.und.nodak.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers3.html

  1. Have students fill out Part A of the Core Sample Worksheet.
  2. Next have each group take their three straws (each student manipulates one straw) and plunge them into the sample. Next, they should remove the straws to reveal three core samples.
  3. Have students use scissors to carefully cut open the straw. They should use caution when cutting near the clay plug, so as to not smash the clay.
  4. Remove the clay plug.
  5. Instruct students to fill out part B of the Core Sample Worksheet.
  6. Go over the worksheet with students.
  7. Students should write a short diary entry from the point of view of an engineer who has just discovered the layers of the Earth by core sampling. Instruct students to include their feelings, concerns, questions and thoughts about the experience.


Troubleshooting Tips

What should happen:

  • The students should get a nice core sample contained in the straw with clearly defined layers.

Oops, it did not happen. Why?

  • The layers mixed or smashed together. ­ The clay is too soft. Allow the clay to dry for a short time after creating the different earth samples. Do not let it become too dry to let the straws cut the clay.
  • After cutting the straw, the core sample got smashed. ­ Since this is a delicate process, have an adult try it again using a razor blade.


Pre-Activity Assessment

Brainstorming: Ask a question and solicit student answers. Remind students that in brainstorming, no idea or suggestion is "silly." All ideas should be respectfully heard. Encourage wild ideas and discourage criticism of ideas. You do not have to provide the right answer, but tell students they will find out during the activity. Ask the students:

  • Do you know how engineers find oil? Any ideas?

Activity Embedded Assessment

Prediction: Have students predict whether or not they will strike oil in their core samples. They will record their prediction on their worksheet.

Worksheet/Pairs Check: Have students work individually on the Core Sample Worksheet. Students should exchange their worksheet with another group member to check/compare answers.

Post Activity Assessment

Dear Diary: Students should write a short diary entry from the point of view of an engineer who has just discovered the layers of the Earth by core sampling. Instruct students to include their feelings, concerns, questions and thoughts about the experience.

Activity Extensions

Create fossil fuels in a soda bottle. For more information see the following website: http://teachcoal.org/lesson-plan-coal-formation. Instructions:

  • Remove the label from a 2-liter plastic soda bottle. Add a 2-inch layer of sand or silt on the bottom, Add about 4 inches of water. Let the sand settle, and then add some twigs, leaves and other organic matter on top.
  • After two weeks, add a second 2-inch layer of silt or sand to the top.
  • Wait another two weeks, and then pour out any remaining water.
  • Wait another week, and observe the fossil fuels you have made.





Jessica Todd; Melissa Straten; Malinda Schaefer Zarske; Janet Yowell


© 2004 by Regents of the University of Colorado.

Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder


The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: September 29, 2017