Earth's Surface


  • Cementation: The process by which dissolved minerals crystallize and glue particles of sediment together into one mass.
  • Cleavage: A mineral's ability to split easily along flat surfaces.
  • Conservation: The process of using a resource wisely so it will not be used up.
  • Convection current: The movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another.
  • Convergent boundary: A plate boundary where two plates move toward each other.
  • Core: Earth's dense center, made up of both the solid inner core and the molten outer core.
  • Crust: The layer of rock that forms the Earth's outer surface.
  • Density: The amount of mass in a given space computed by mass per unit volume.
  • Deposition: The process by which sediment settles out of the water or wind that is carrying it, and is deposited in a new location.
  • Divergent boundary: A plate boundary where two plates move away from each other.
  • Earthquake: The shaking that results from the movement of rock beneath Earth's surface.
  • Erosion: Process by which wind, ice, or water and gravity move rock and soil.
  • Fracture: The way a mineral looks when it breaks apart in an irregular way.
  • Hardness: The level of the minerals calcium and magnesium in water.
  • Humus: Dark colored organic material in soil.
  • Igneous rock: A type of rock that forms from the cooling of molten rock at or below the surface.
  • Index Fossils: Fossils of widely distributed organisms that lived during only one short period.
  • Lava: Magma that reaches the surface; also the rock formed when liquid lava hardens.
  • Lithosphere: A rigid layer made up of the uppermost part of the mantle and the crust.
  • Magma: Molten mixture of rock-forming substances, gases, and water that makes up part of Earth's mantle.
  • Mantle: The layer of hot, solid material between Earth's crust and core.
  • Metamorphic rock: A type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions.
  • Mineral: A naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition.
  • Mohs hardeness scale: A scale ranking ten minerals from softest to hardest; used in testing the hardness of minerals.
  • Pressure: The amount of force pushing on a surface or area.
  • Rift Valley: A deep valley that forms where two plates move apart.
  • Sedimentary rock: A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together.
  • Soil: The loose, weathered material on Earth's surface in which plants can grow.
  • Streak: The color of a mineral's powder.
  • Temperature: The average amount of energy of motion in the molecules of a substance.
  • Texture: The size, shape, and pattern of a rock's grains.
  • Trace Fossils: A type of fossil that provides evidence of the activities of ancient organisms.
  • Tsunami: A giant wave caused by an earthquake on the ocean floor.
  • Unconformity: A place where an old, eroded rock surface is in contact with a newer rock layer.
  • Volcano: A weak spot in the crust where magma has come to the surface.
  • Weathering: The chemical and physical processes that break down rock at Earth's surface.

Experiments/Activities: Use these to help you understand concepts.

  • Sandwich Strata: Find out about rock layers with your favorite sandwich!
    1. Make a sandwich with several different materials. Then use a round, hollow, uncooked pasta noodle to take a core sample. Push the noodle through the layers of the sandwich.
    2. Pull the noodle out of the sandwich and break it gently to remove your core sample.
    3. Observe/draw a picture coloring and labeling what you see in each layer of the core. If this were a real rock layer sample what would be the oldest layer? The youngest? Why do scientists study core samples?
  • Fossil Fun:
    1. Wrap a piece of clay around one sugar cube so that half of it is covered with clay.
    2. Wrap clay entirely around a second sugar cube and seal it tightly.
    3. Drop both cubes into a bowl of water, along with an uncovered sugar cube.
    4. Stir until the uncovered sugar cube dissolves completely.
    5. Remove the other cubes from the water and examine the remains. Describe what the sugar cubes look like now. Did the clay preserve the sugar cubes? How does this activity model the way fossils form?
  • Glacier Erosion
    1. Put some sand in a small plastic container.
    2. Fill the container with water and place in the freezer until it turns completely into ice.
    3. Remove the block of ice from the container.
    4. Holding the ice with paper towels, rub the ice, sand side down, over a bar of soap. Observe what happens to the surface of the soap. Based on what you observed how do you think moving ice changes the surface of the land?
  • Deposition Mania
    1. Obtain a clear plastic jar or bottle with a top. Fill about two-thirds full with water.
    2. Fill a plastic beaker with some of the following ingredients: fine and course sand, soil, clay, and small pebbles.
    3. Pour the mixture into the jar of water, Screw on the top tightly and shake for two minutes.
    4. Set the jar down and observe it for 10 to 15 minutes. In what order were the sediments in the jar deposited? What do you think causes this pattern?