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Geolens

Teachers

A lesson for your classroom or geography club

Karst

All teacher notes · Open the lab

Start projector

People cross pale limestone blocks separated by deep joints above Malham Cove, England.
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Malham Cove limestone pavement. Rainwater containing dissolved carbon dioxide widens joints into grykes, leaving blocks called clints.

A suggested lesson sequence

Use these stages at your own pace. Pause for students to sketch, compare observations or lead part of the demonstration.

  1. 01

    Observe

    Identify clints, grykes and the surface depression.

    Open Observe

  2. 02

    Tinker

    Open Cutaway and follow the selected route towards the spring.

    Open Tinker

  3. 03

    Explain

    How do joints and slightly acidic water influence the development of limestone passages?

    Open Explain

  4. 04

    Check

    Choose an answer and explain your reasoning. Each question includes feedback.

    Open Check

Rehearse with the model

The same scene and controls as the lab. Load it when you are ready; use Start projector for the full classroom view.

Before the lesson

Explain how water dissolves limestone along joints to form surface grooves, sinkholes and underground passages.

Open the model before the lesson and choose a view that makes the important feature easy to see. Drag to rotate, and use the on-screen controls to change one variable at a time. The Controls panel explains the available keyboard shortcuts.

Pause the animation at a useful moment. Ask students what should happen next, then play it to test their explanation.

Guide the demonstration

Identify clints, grykes and the surface depression.

Open Cutaway and follow the selected route towards the spring.

Discuss a common misconception

“An underground drainage basin must have exactly the same boundary as the surface basin.” Water in soluble rock can follow connected fractures and passages beneath a surface divide. Its underground route may therefore lead to a different outlet from the one suggested by topography. Dye tracing and other observations can help establish the actual groundwater connections.

Build the explanation

Water containing dissolved carbon dioxide can dissolve calcite along joints and bedding planes. Connected openings can develop into underground drainage routes, while calcite may later precipitate where carbon dioxide escapes.

Open Cutaway and follow the selected route towards the spring.

The cutaway illustrates connected passages and the reaction; it does not calculate cave growth rates or water quality.

Teaching notes

Connect solution landforms with water moving through soluble rock rather than assuming every hollow is volcanic.

Distinguish limestone solution caves from lava tubes formed during volcanic activity.

Use an appropriate soluble rock, such as limestone, when explaining the development of karst.

Check understanding

Open Check for 4 questions. Ask students to explain their choice before revealing the answer.

Return to the opening photograph. Ask students to identify one visible feature and explain which part of the model helps account for it.

Look more closely

Use these observations to connect the vocabulary to features students can identify.

Swallow hole

A rocky opening in grassy limestone terrain at Stream Passage Pot in the Gaping Gill cave system.
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Stream Passage Pot, Ingleborough, North Yorkshire. This entrance belongs to the Gaping Gill karst drainage system, where surface water enters underground passages.
Read the definition

Resurgence

A karst spring in Alabama flows over rocks from a wooded limestone slope.
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Groundwater emerges at a karst spring in Alabama. Water stored in connected pores and fractures can return to the surface as spring flow.
Read the definition

Sources to keep beside the lesson

Same realm