Grade Level: K-6

ACF Lesson Plan: Coal Formation


Students conduct a simulation of the formation of coal and practice the essential laboratory skills of hypothesizing, observing, and explaining their findings.


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Students will:

  1. observe change over time through the simulation of forming coal through fossilizing plant materials, and
  2. practice scientific inquiry by conducting a simulation to practice the skills of hypothesizing, observing, and describing the process and results of an experiment.

National Standards:

National Science Education Standards (NSES)

  • Science as Inquiry, K-4, 5-8
    • Abilities necessary to do scientific inquiry
  • Physical Science, 5-8
    • Properties of matter and changes in properties of matter

Time Needed:

Approximately four class periods, over four or five weeks


  • One small aquarium for classroom setup, or several 2-liter soda bottles with the tops cut off, for multiple small-group experiments
  • Enough fine- to medium-grain sand to cover 2 inches of each aquarium
  • Fern fronds (leaves)
  • Twigs
  • Plant leaves
  • Screen(s) or sifter(s)
  • Fine silt or mud
  • Student science journals
  • Coal Fossil Record Sheet

Discussion Questions:

  • What does it mean to simulate a process?

  • What is a fossil? What is a fossil fuel?

  • What do you know about how coal is formed?


  1. Begin by reviewing the definition of simulation. Explain to students that to simulate a process is to imitate it or create a model that shows how that process occurs. When we simulate a process like coal formation, for example, we study what conditions exist for coal to form from fossilized plant materials. A simulation does not need to be an exact replication of a process for it to demonstrate how something happens in the natural world.

  2. Tell students they will create their own (or a classroom) “fossil” over the course of the next four weeks and will observe how that fossil forms.

  3. Explain that coal is an example of a fossil fuel. Remind students that a fossil fuel is a fuel that has formed in the earth from the remains of plants or animals that lived as long as 400 million years ago. Ask students: Can you think of other fossil fuels (e.g., oil, natural gas)? Coal is formed from a combination of plant material, heat, pressure, and time. The process of coal formation takes millions of years to complete and is still taking place today. Although students will not actually create coal in this activity, they will see how the fossilization process occurs.

  4. Begin the experiment by separating students into small groups or by creating a single aquarium for the class to study. Line the aquarium(s) with plastic wrap so that you can lift the entire formation out when it is dry. Next, pour water into each aquarium to a depth of 4 to 6 inches. Then spread about 2 inches of sand on the bottom, followed by small leaves, sticks, and pieces of fern.

  5. Once each aquarium is set up, have students record their observations in their Coal Fossil Record Sheet. Students should describe what the aquarium looks like, as well as what textures and colors they notice in the sand and foliage. Ask them what changes they think might occur over a few weeks if the aquarium is left untouched. Have them record their hypotheses in their record sheet. Tell them to watch the aquarium change over the course of the next four weeks. Each day, have them record any changes in color and water level.

  6. After two weeks, use the screen or sifter to gently sift fine silt or mud on top of the plant layer to a depth of 2 inches. This replicates the natural fossilizing process of contributing heat and pressure to the vegetation. Make sure students continue to document any changes they see. They should adjust their hypotheses if necessary.

  7. Wait another two weeks and drain any water that remains. Let the formation sit and dry for another week or two. Once it is dry, carefully lift the entire formation out of the container(s). Tell the students they have simulated the early stages of coal formation. Gently break the formation into layers to reveal the fossil-like imprints from the plants.


Have students prepare a summary of the simulation, including how it was set up and how it changed (before and after intervention). Then have each student determine whether his or her hypothesis was correct. Students may create a power point presentation based on the pictures they take each day during the simulation. Include their findings established from their Coal Fossil Record Sheet.


To make the most of each student’s strengths, arrange the teams so that each consists of students with good observational skills and students with good writing skills. Allow them to discuss their observations and prepare their record sheets together.

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