Rock Cycle - Rocks (3B)
Post Lab 

  • Comparing sand formed by wind and water.
  • Writing and reading poems on sand.
  • erosion
  • none

Students write a poem using sand to help create images.

Montara Beach Sand, California


The agents of erosion (water, wind, ice, heat) remove particles from a parent rock. These loosened particles are named by their size. Large particles are called boulders and cobbles, smaller particles sand, and the smallest silt and mud. When weathering and erosion begin, the loose material consists of a wide range of particle sizes. However, as erosion progresses, the larger particles break down to smaller sizes. The amount of sand thus increases as erosion continues. Geologists have assigned specific particle diameters to each of these categories.

Sand has been used to describe many human qualities. A vagabond has been referred to as "driftless like ...sand;" endless time is "sand that drifts forever;" we are all but a "grain of sand on the beach." Children can spend endless hours on the beach, creating sand castles, or digging to reach the other end of the world. It can cover you up, but not make you dirty. Sand is clean to play with. Children look at sand falling through an hour glass fascinated by every grain that falls and some paint with different color sands to create works of art. Sand is loved so much by children that adults have created sand boxes, so their children can play.

Its funny to think that sand can be associated with two very opposite climatic conditions. Water that crashes upon beaches along the ocean, lake or river with the hot sun and wind that shifts sand in deserts like Death Valley and the Sahara Desert. But if you understand the process that creates sand, you can see that in both situations some kind of erosion of the surrounding rock is creating the sand.

Sand is but the Earth in miniature. Every rock which makes up the earth, succumbs to erosion and will become sand with time. (This process is part of the rock cycle.) Mighty mountains are slowly chipped away by natural forces like wind and rain; and over long periods of time, the mountains will become sand.

  1. Read the following two poems to the students.
    Julia A. Fletcher

    Little drops of water,
    Little grains of sand
    Make the mighty ocean
    And the pleasant land.
    Thus the little minutes,
    Humble though they be,
    Make the mighty ages
    Of Eternity.

    SAND DUNES - Robert Frost

    Sea waves are green and wet,
    But up from where they die
    Rise others vaster yet,
    And those are brown and dry.
    They are the sea made land
    To come at the fisher town
    And bury in solid sand
    The men she could not drown
    She may know cove and cape,
    But she does not know mankind
    If by any change of shape
    She hopes to cut off mind.
    Men left her a ship to sink:
    They can leave her a hut as well;
    And be but more free to think
    For the one more cast-off shell.

    Discuss the poems with the students. Point out that both poems deal with erosion.

  2. Following your discussion you may have students write their own "erosional poems." This activity might be more successful if students work in small groups.

[Back to Rock Cycle Grid]   [Back to Rocks (3)]