Lesson 99 - Rocks 1-21 Flashcards
Minerals
A solid material made of one substance that occurs naturally on Earth
Rocks
Natural Solids formed from one or more minerals
Properties
Certain things about a rock or mineral that geologists use to help identify it. Some properties include the color, hardness, texture or the color of the streak that the rock or mineral leaves behind.
Fossils
The imprint or remains of something that lived long ago. Can be found in sedimentary rock. Gives us information about the Earth’s past.
Sediments
Little bits and pieces of rocks and sand
Weathering
The process that causes rocks to crumble, crack and break down. Water, wind, ice, chemicals in the air, plants and animals can all cause weathering of rocks.
Erosion
The carrying away or movement of soil, mud or rocks. Movement can be caused by water, wind, ice, movement in response to gravity or living organisms.
Sedimentary rock
Rocks that are in layers of sand, mud or pebbles (sediment6) that were pressed together by water. Fossils are usually found in sedimentary rock. Examples are limestone and sandstone.
Igneous rock
Rocks that form when melted rock cools and hardens. Igneous rocks are called fire-made rocks. Examples are granite and pumice.
Metamorphic rock
Rocks that have changed form due to the heat and pressure of the earth.
Soil
A mixture of rock particles, decayed plant and animal remains called humus, air and water.
Sand
Sand has large rock particles so it feels rough and gritty. Water passes quickly through it so plant roots may not be able to soak up the water fast enough in this type of soil.
Silt
Silt has medium-sized particles that are more closely packed together. When it’s wet, it feels slippery and smooth. Although water does pass through it, silty soil holds water better than soil.
Clay
Clay particles are the smallest. When clay is wet, it feels smooth and sticky. Clay holds water so well, that a plant may drown if the roots don’t get enough air.
