Geography Functional Chapter 1 Experiment 13 Stratification of Rocks from a Folded Mountain

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  • Experiment 13: Four colors of play-dough or plasticine, a circular disc of cardboard with a diameter of about 30 cm, oiled paper, a serrated knife, a rolling pin, a ruler, a pencil, and scissors


  • Teacher should have conducted the First Great Lesson: God Who Has No Hands/The Universe Story before beginning these experiments.
  • Chapter 1 of Functional Geography is Formation of the Earth and includes Impressionistic Charts 1-6
  • Functional geography curriculum focuses on a presentation of the world in terms of the active and functioning processes affecting the earth as a planet in the sun's family. Geography examines the social and cultural contexts of the world while functional geography explores the geological and astronomical contexts of the earth in the universe.
  • When we teach functional geography to the child, we are both performing and recording with words and pictures the forces affecting our planet earth.
  • Functional Geography is presented to the child as an experiment which isolates a concept and then an impressionistic chart which makes a visual impression.


Experiment 13 is part of the MOVEMENT IN THE LITHOSPHERE experiments: Of all the parts of the solid earth, the one we know most about is the lithosphere. It is the part that has greatly changed through time. During the cooling process and also because of the corrosive work of water, the earth's crust corrugated; the oceans and lakes were formed, etc. The earth is still changing. This changing process is slower than before because the earth is not barren as it was before. We are not aware of these transformations because man's life span in comparison to the age of the earth is minimal. An example to us: the mountains seem eternal, whereas in relation to the age of the earth, mountains are something which appear and disappear with time. (For example, there are some mountain chains which are growing between India and China and between Yugoslavia and Greece, and in the ocean.)

    The earth's surface is not still. It is constantly in motion. If the surface rises, the mountains rise. However, the mountains also suffer because of the work of erosion. If the surface is depressed, a sediment depression is formed, and in time these depressions are filled in by the erosive work of water and wind. The matter in these depressed regions accumulates with time.

Experiment 13: This experiment illustrates the building up of strata into a mountain. It then demonstrates what happens when the mountain is worn away by erosion: a plateau plain is formed.

  • 1. Construct a model of a common mountain with one color (grey if you have it). Make the base a diameter of 8 inches, and an altitude of about 6 inches.
  • 2. Cut a circle of oil paper the same diameter of the cardboard disk and then place it on top of the disc. Place the constructed mountain on the disc.
  • 3. Choose another color of dough, roll it out to make a circular sheet with a diameter of about 12 inches and thickness a little more that 1/4 inch. Place the center of the sheet exactly at the top of the mountain, press and mold to the existing mountain. Remove any excess. The sides of the mountain have in this way, changed color.
  • 4. Repeat the process with the two other colors. If possible, use a brick-color for the final layer.

The different layers represent stratifications. That is, the successive deposits of sediments. The principle of the supposition of stratification states that in any sequence of strata, not later disturbed, the order in which they were deposited is from bottom to top. The first layer that forms the mountain is at the center. The outer layer of the mountain is the most recent. The center of a plateau from a folded mountain is the oldest layer; the outer layer is the most recent layer.

  • 5. Slice the top of the mountain, giving the origin to a special plateau from a folded mountain.

Record your observation:

Note: In the basin of sedimentation, the color grey is on the outside; in the plateau of the mountains, it is in the center. In the basin of sedimentation, brown, the most recent layer, is in the center; in the mountain, it is on the outside.

  • Up until now, we have discussed the strata of the earth, and the child has experienced these strata in terms of clay, cloth, etc. To avoid having the child identify the strata of the earth with clay or cloth, it is necessary to explain that the strata of the earth are made of rock. This started, in the case of some rocks, with the settling of layers of dust, which, because of tremendous pressure become rock.

CLASSIFIED NOMENCLATURE: The Three Types of Rocks: Igneous, sedimentary, metamorphic

    At the beginning of the earth's history, its crust was made up primarily of igneous rocks. These rocks were formed from lava which hardened as it cooled. A great part of this lava solidified before it reached the earth's surface. It solidified beneath the surface, and from this solidification the granite rocks were formed. The lava which solidified after it reached the surface of the earth formed basalt, volcanic rocks (rhyolite - basalt). These rocks of volcanic origin do not contain fossils, and they are not formed in layers. 
    The sedimentary rocks are the most interesting ones. They are formed at different periods and, therefore, are in layers. They often contain fossils and, therefore, are helpful to the study of primitive life on earth. They also allow scientists to date the age of the rock. The various strata of these rocks are materials deposited by wind, water, by chemical precipitations, or by deposits of organic matter (the skeletons of animals). An easy experiment to illustrate deposits left by water which evaporates: place salt in water; boil the water until it evaporates, and the salt will remain.
    There are many rocks of sedimentary origin. For example: sandstone, chalk, clay, limestone.
    Metamorphism means to change form. Metamorphic rocks can form from igneous, sedimentary, or other metamorphic rocks as a result of heat, pressure, or chemically active fluids. When subjected to intense heat and directional pressure, the rocks bend into intricate folds. Metamorphism occurs during mountain building, magma contact, or faulting. The study of rocks is very important because it helps us to understand the earth and its processes. 


Control Of Error

Points Of Interest

The classified nomenclature is usually presented before the impressionistic charts and after the experiments, but can also be parallel to the charts. Since the classified nomenclature can be very long, it is not necessary to present all of the classified nomenclature before beginning the charts.


  • The Montessori methodology first gives the concept of the formation of the earth through experiments. These experiments are the key to giving the child the concrete verification that the universe is not a static universe, but one in which elements are in motion.


  • Usually, the teacher presents the experiment first, and the the child does it independently using the direction card for directions. With the older children, the experiments are presented in a more scientific way.


Possible Research Choices: 1. Practical demonstration of the force of gravity. 2. The earthquakes: A. A visit to a seismographic center. B. Locate the seismic areas of the earth. C. A graph of earthquakes. C. A collection of pictures of changes made by an earthquake. 3. An experimental construction of a chart with the specific weight of the most common matter. 4. A collection of minerals and fossils and their classification according to the region of origin. A visit to a museum of natural history. 5. Observe in the natural environment the stratification of rocks. Drawing activity.