Third Grade Earth Science Vocabulary
geology- the study of the earth, especially through rocks and minerals
geologist- a scientist who studies the earth, rocks, and minerals
rock- a piece of stony material found in the earth’s crust made of one or more minerals; rocks are nonliving
mineral- a natural, chemical substance found in the earth. Minerals are used for many purposes. (ex. copper in pennies, graphite in pencils, iron in food, etc.)
Properties of Rocks and Minerals: shiny, smooth, rough, spotted, sparkly, bumpy, jagged, magnetic, transparent (see-through), translucent (can somewhat see though but not clearly), opaque (cannot see through)
***There are many other properties, these are just some examples.
crust- the rocky outer layer of the earth where most rocks and minerals are found; It surrounds the earth like a hard shell.
mantle- the thick layer of the earth made of heavy rocks that support the crust. Rock begins to melt in the deepest part of the mantle.
outer core- the layer of the earth made of magma, or molten iron and nickel (liquid rocks, minerals, and metals)
inner core- the center of the earth, and the hottest part; made of solid iron and nickel because the weight of the earth presses down on the inner core
3 Main Categories of Rocks:
sedimentary rocks- rocks that are formed by sediments (small bits of rock or soil) These sediments gather together, push together, and harden into new rocks. It takes thousands of years for these rocks to form.
igneous rocks- rocks that are formed from magma that has cooled inside the earth, or from lava that has erupted from a volcano and cooled and hardened
metamorphic rocks- rocks that are formed when heat and pressure cause one type of rock to change into another type of rock.
soil- the upper layer of the earth that contains pieces of rock, clay, sand, air, water, and organic material (tiny bits of dead plant, insect, and animal parts)
Properties of Soil
1. color
2. texture (how it feels)
3. ability to hold water
4. ability to grow plants
Layers of Soil
topsoil- often dark in color, about 8 inches deep; This layer is where some living things make their homes and where seeds and roots find the water and nutrients they need to grow.
subsoil- This layer is a mix of clay, sand, and loose pieces of rock. It is often lighter in color than topsoil.
bedrock- This layer is made up of solid rock.