6th Grade Earth Science








Chapter 1 Vocabulary
  • system- A group of objects of phenomena that interact.  It can be as simple as a rope, a pulley, and a mass.  It also can be as complex as the interaction of energy and matter in the four parts of the Earth system.
  • atmosphere-The outer layer of gases of a larger body in space, such as a planet or star; the mixture of gases that surrounds the solid Earth; one of the four parts of the Earth system.
  • hydrosphere-All water on Earth--in the atmosphere and in the oceans, lakes, glaciers, rivers, streams, and underground reservoirs; one of the four parts of the Earth's system.
  • biosphere-All living organisms on Earth in the air, on the land, and in the waters; one of the four parts of the Earth system.
  • geosphere-All the features on Earth's surface--continents, islands, and seafloor--and everything below the surface--the inner and outer core and the mantle.
  • relief map-A map that show the differences in elevation in an area.  Relief maps can show elevations through the use of contour lines, shading, colors, and in some cases, three-dimensional materials.
  • map scale-The comparison of distance on a map with actual distance on what the map represents, such as Earth's surface.  Map scale may be expressed as a ratio, a bar scale, or equivalent units.
  • map legend-A chart that explains the meaning of each symbol used on a map; also called a key.
  • equator-An imaginary east-west line around the center of the earth that divides the planet into the Northern Hemisphere and the Southern Hemisphere.
  • latitude-The distance in degrees north or south from the equator.
  • prime meridian-An imaginary north-south line that divides the planet into the Eastern Hemisphere and the Western Hemisphere.  The prime meridian passes through Greenwich, England.
  • longitude-The distance in degrees east or west of the prime meridian.  Longitude lines are numbered from 0 degrees to 180 degrees.
  • projection-A representation of Earth's curved surface on a flat map.
  • topography-All natural and human-made surface features of a particular area.
  • contour line-A line on a topographic map that joins points of equal elevation-A measure of how high something is above a reference point, such as sea level
  • elevation
  • slope-A measure of how steep a landform is.  Slope is calculated as the change in elevation divided by the distance covered.
  • relief-In geology, the difference in elevation between an area's high and low points.
  • contour interval--On a topographic map, the difference in elevation between one contour line and the next.
  • remote sensing-A method of using scientific equipment to gather information about something from a distance.  Most remote sensing methods make use of different types of electromagnetic radiation.
  • sensor-A mechanical or electronic device that receives and responds to a signal, such as light.
  • false-color image-A computer image in which the colors are not what the human eye would see.  A false-color image can assign different colors to different types of radiation coming from an object to highlight its features.
  • geographic information systems-Computer systems that can store, arrange, and display geographic data in different types of maps.


Chapter 2/Sixth Grade Science Vocabulary

  • mineral - A substance that forms in nature, is a solid, has a definite chemical makeup, and has a crystal structure.
  • element - A substance that cannot be broken down into a simpler substance by ordinary chemical changes. An element consists of atoms of only one type.
  • crystal - A solid substance in which the atoms are arranged in an orderly, repeating, three-dimensional pattern.
  • streak -The color of a mineral powder left behind when a mineral is scraped across a surface; a method for classifying minerals.
  • luster - The property of a mineral that describes the way in which light reflects from its surface. Major types of luster are metallic and nonmetallic
  • cleavage - The property of a mineral that describes its tendency to break along flat surfaces.
  • fracture - The tendency of a mineral to break into irregular pieces.
  • density - A property of matter representing the mass per unit volume.
  • hardness - The resistance of a mineral or other material to being scratched.
  • magma - Molten rock beneath Earth’s surface.
  • lava - Molten rock that reaches a planet’s surface through a volcano.
  • ore - A rock that contains enough of a valuable mineral to be mined for a profit.


Chapter 3 Vocabulary
  • rock - A naturally formed solid that is usually made up of one or more types of minerals
  • rock cycle - The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • igneous rock -The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • sedimentary rock-The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • metamorphic rock -The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • intrusive igneous rock -The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • extrusive igneous rock -The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • sediment -The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • metamorphism -The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • recrystallization -The set of natural, repeating processes that form, change, break down, and re-form rocks.
  • foliation -The set of natural, repeating processes that form, change, break down, and re-form rocks.


Chapter 4/Vocabulary

  • Weathering - The process by which natural forces break down rocks.
  • mechanical weathering - The breakdown of rock into smaller pieces of the same material without any change in its composition.
  • exfoliation - In geology, the process in which layers or sheets of rock gradually break off.
  • abrasion - The process of wearing something down by friction.
  • chemical weather - The breakdown or decomposition of rock that takes place when minerals change through chemical processes.
  • humus - The decayed organic matter in soil.
  • soil horizon - A soil layer with physical and chemical properties that differ from those of soil layers above or below it.
  • soil profile - The soil horizons in a specific location; a cross section of soil layers that displays all soil horizons.
  • desertification - The expansion of desert conditions in areas where the natural plant cover has been destroyed.

Chapter 5 Vocabulary
1.Erosion – Water, wind, and ice move sediment in the process called erosion.
2.Deposition – The process in which transported sediment is laid down.
3.Mass wasting – The downhill movement of loose rock or soil.
4.drainage basin-An area of land in which water drains into a stream system. The borders of a drainage basin are called divides.
5.Divide - A continuous high line of land (or ridge) from which water drains to one side or the other.
6.Floodplain - A flat area of land on either side of a stream that becomes flooded when a river overflows its banks.
7.alluvial fan - A fan-shaped deposit of sediment at the base of a slope, formed as water flows down the slope and spreads at the bottom.
8.Delta - An area of land at the end, or mouth, of a river that is formed by the buildup of sediment.
9.Sinkhole - An open basin that forms when the roof of a cavern becomes so thin that it falls in.
10.Longshore drift - The zigzag movement of sand along a beach, caused by the action of waves.
11.Longshore current - The overall direction and movement of water as waves strike the shore at an angle.
12.Sand bar - A ridge of sand built up by the action of waves and currents.
13.Barrier island - A long, narrow island that develops parallel to a coast as a sandbar builds up above the water’s surface.
14.Dune - A mound of sand built up by wind.
15.Loess - Deposits of fine-grained, wind-blown sediment.
16.Glacier -A large mass of ice that exists year-round and moves over land.
17.Till - Sediment of different sizes left directly on the ground by a melting, or retreating, glacier.
18.Kettle lake - A bowl-shaped lake that was formed as sediment built up around a block of ice left behind by a glacier.
19.Moraine - A deposit of till left behind by a retreating glacier. Moraines can form along a glacier’s sides and at its end.

Vocabulary - Chapter 6
1.  inner core - A solid sphere of metal, mainly nickel and iron, at Earth’s center.
2.  outer core - A layer of molten metal, mainly nickel and iron, that surrounds Earth’s inner core.
3   mantle - The layer of rock between Earth’s outer core and crust, in which most rock is hot enough to flow in convection currents; Earth’s thickest layer. The layer of rock between Earth’s outer core and crust, in which most rock is hot enough to flow in convection currents; Earth’s thickest layer.
4. crust - A thin outer layer of rock above a planet’s mantle, including all dry land and ocean basins. Earth’s continental crust is 40 kilometers thick on average and oceanic crust is 7 kilometers thick on average.
5. lithosphere -  The layer of Earth made up of the crust and the rigid rock of the upper mantle, averaging about 40 kilometers thick and broken into tectonic plates. The layer of Earth made up of the crust and the rigid rock of the upper mantle, averaging about 40 kilometers thick and broken into tectonic plates.
6. asthenosphere - The layer in Earth’s upper mantle and directly under the lithosphere in which rock is soft and weak because it is close to melting.
7. tectonic plate - One of the large, moving pieces into which Earth’s lithosphere is broken and which commonly carries both oceanic and continental crust.
8. continental drift - The hypothesis that Earth’s continents move on Earth’s surface.
9. Pangaea - A hypothetical supercontinent that included all of the landmasses on Earth. It began breaking apart about 200 million years ago.
10. mid-ocean ridge -  A long line of sea-floor mountains where new ocean crust is formed by volcanic activity along a divergent boundary.
11. convection -  A process by which energy is transferred in gases and liquids, occurring when a warmer, less dense area of gas or liquid is pushed up by a cooler, more dense area of the gas or liquid.
12. convection current - A circulation pattern in which material is heated and rises in one area, then cools and sinks in another area, flowing in a continuous loop.
13. theory of plate tectonics - A theory stating that Earth’s lithosphere is broken into huge plates that move and change in size over time.
14. divergent boundary - A boundary along which two tectonic plates move apart, characterized by either a mid-ocean ridge or a continental rift valley.
15. convergent boundary -  A boundary along which two tectonic plates push together, characterized either by subduction or a continental collision.
16. transform boundary - A boundary along which two tectonic plates scrape past each other, and crust is neither formed nor destroyed.
17. rift valley -  A deep valley formed as tectonic plates move apart, such as along a mid-ocean ridge.                                            18. magnetic reversal - A switch in the direction of Earth’s magnetic field so that the magnetic north pole becomes the magnetic south pole and the magnetic south pole becomes the magnetic north pole.
19. hot spot - An area where a column of hot material rises from deep within a planet’s mantle and heats the lithosphere above it, often causing volcanic activity at the surface.
20. subduction - The process by which an oceanic tectonic plate sinks under another plate into Earth’s mantle.
21.continental-continental collision - A boundary along which two plates carrying continental crust push together.
22. oceanic-oceanic subduction - A boundary along which a plate carrying oceanic crust sinks beneath another plate with oceanic crust.
23. oceanic-continental subduction - A boundary along which a plate carrying oceanic crust sinks beneath a plate with continental crust.


Chapter 11 Vocabulary

1.  fresh water - Water that is not salty and has little or no taste,         color, or smell. Most lakes and rivers are made up of fresh             water.
2.  salt water - Water that contains dissolved salts and other               minerals. Oceans consist of salt water.
3.  water cycle - The continuous movement of water on Earth,             through its atmosphere, and in the living things on Earth.
4.  evaporation - A process by which a substance changes from         its liquid state to its gas state by random particle movement.         Evaporation usually occurs at the surface of a liquid over a           wide range of temperatures.
5.  condensation - The process by which a gas changes into a            liquid.
6.  precipitation - Any type of liquid or solid water that falls to            Earth’s surface, such as rain, snow, or hail.
7. divide - A continuous high line of land (or ridge) from which         water drains to one side or the other.
8.  drainage basin - An area of land in which water drains into a         stream system. The borders of a drainage basin are called             divides.
9.  turnover - The yearly rising and sinking of cold and warm              water layers in a lake.
10.eutrophication - An increase in nutrients in a lake or pond.           Eutrophication can occur naturally or as a result of pollution,        and causes increased growth of algae and plants.
11.iceberg - A mass of floating ice that broke away from a glacier.
12.groundwater - Water that collects and is stored underground
13.permeable -  Allowing the passage of water.
14.impermeable - Resistant to the passage of water.
15.water table - The highest part in the ground that is saturated, or completely filled with water.
16.aquifer -  An underground layer of permeable rock that                   contains water.
17.spring - A flow of water from the ground at a place where the         surface of the land dips below the water table.
18. artesian well - A well in which pressurized water flows                    upward to the surface.

VOCABULARY CHAPTER 16
1.  air pressure - The force of air molecules pushing on an area.
2. barometer - An instrument that measures air pressure in the atmosphere.
3.  weather - The condition of Earth’s atmosphere at a particular time and place.
4.  wind - The horizontal movement of air caused by differences in air pressure.
5.  global wind - Winds that travel long distances in steady patterns over several weeks.
6.  Coriolis effect - The influence of Earth’s rotation on objects that move over Earth.
7.  jet stream - A wind that flows in the upper troposphere from west to east over vast distances at great speeds.
8.  monsoon - A wind that changes direction with the seasons.
9.  evaporation - The process by which a gas changes into a liquid.
10.  condensation - The process by which a gas changes into a liquid.
11.  precipitation - Any type of liquid or solid water that falls to Earth’s surface, such as rain, snow, or hail.
12.  humidity - The amount of water vapor in air.
13.  saturation - A condition of the atmosphere in which the rates of evaporation and condensation are equal.
14.  relative humidity - The comparison of the amount of water vapor in air with the maximum amount of water vapor that can be present in air at that temperature.
15.  dew point - The temperature at which air reaches saturation.
16.  freezing rain - Rain that freezes when it hits the ground or another surface and coats the surface with ice.
17.  sleet - Small pellets of ice that form when rain passes through a layer of cold air and freezes before hitting the ground. 
18.  hail - Layered lumps or balls of ice that fall from cumulo-nimbus clouds.
19.  acid rain - Rain that has become more acidic than normal due to pollution.