RocksRocks

Key VocabularyKey Vocabulary

• Rock = is a naturally formed solid that is usually made up of one or more types of minerals

• Rock Cycle= is the set of natural processes that form, change, break down and re-form rocks.

Types of Rocks

• Igneous

• Sedimentary

• Metamorphic

Igneous Rock VocabIgneous Rock Vocab

• Igneous rock = forms when molten rock cools and becomes solid

• Intrusive igneous rock = forms when magma cools within Earth

• Extrusive igneous rock = forms when lava cools on earth’s surface.

Sedimentary Rock VocabSedimentary Rock Vocab

• Sediments are materials that settle out of water or air.

• Sedimentary rock = forms when pieces of older rocks, plants, and other loose material get pressed or cemented together.

Metamorphic Rock VocabMetamorphic Rock Vocab

• Metamorphic rock= forms when heat or pressure causes older rocks to change into new types of rocks

• Metamorphism = process in which existing rock is changed by heat, pressure, or by both.

Metamorphic Rock VocabMetamorphic Rock Vocab

• Recrystalization – the process by which bonds between atoms re-form in new ways.

• Foliation = is an arrangement of minerals in a flat or wavy parallel bands.

Main Classification of RocksMain Classification of Rocks

• Mineral and Chemical Composition

• Texture

-breaks the rock into the three types of rocks that we will learn about later.

• Particle size

Examples of Rocks With One Examples of Rocks With One MineralMineral

• Limestone is a rock composed entirely of the mineral calcite

• Sandstone is normally composed of only quartz

Examples of Rocks With No Examples of Rocks With No MineralsMinerals

• Obsidian is one of the few rocks with no minerals. It is made up of natural gases.

• Coal is another rock that is not made up of minerals. We use coal for electricity everyday

The Rock CycleThe Rock Cycle

Rock Cycle Notes• A cycle is continuous and never ends• Rocks can change over and over again• Igneous rocks can change to become

igneous, sedimentary, and metamorphic rocks

• Sedimentary rocks can become a sedimentary or metamorphic rock

• A metamorphic rock can become an igneous or sedimentary rock

Interesting FactsInteresting Facts

• All types of rocks can be found above and below ground but……..

• 95% of rocks below ground are igneous and metamorphic rocks

• 75% of rocks above ground are sedimentary rocks

• Why do you think this is the case?

Other types of rocksOther types of rocks

• Meteorites– A rock from space– 30,000 rocks with mass over 100 grams hit

earth every year.– Can be dangerous

Igneous RocksIgneous Rocks

• 2 types are intrusive and extrusive

Examples• Granite and Gabbro are intrusive rocks

• Rhyolite, pumice and basalt are extrusive

Igneous Rocks Textures Igneous Rocks Textures

• Texture is the size of its minerals crystals• Igneous rocks texture depends on how

quickly the magma cooled• The longer it takes to cool the larger the

crystals are• Intrusive rocks cool slower because its still

hot below the earth crust• Extrusive rocks cool faster because its

cooler on the crust then below the crust

Texture ContinueTexture Continue

• Some rocks contain crystals of small and large because part cooled below ground and part above ground

– Worksheet on cooling time

Composition of Igneous rocksComposition of Igneous rocks

• Scientist have to use composition as well as texture. Why?

• Both sugar and salt have small white texture but they are totally different

• Composition is determined by how much silica is in the rock

Sedimentary RocksSedimentary Rocks• Rocks can be found all around us• Weathering = is when wind and water help

create new sediments.• The combination of both is what allows

sedimentary rocks to form• Pressure is what makes the particles push

together to form new rocks• Takes a long time for the pressure to be

strong enough to make the changes

All rocks are not made from rocksAll rocks are not made from rocks

• Some rocks are made from plants and shells

• Coal is made from wood and leaves

• Coral in the ocean is made from limestone and shells from living organisms

History can be toldHistory can be told

• Sedimentary rocks are normally in layers

• If fish fossils are found that would mean water use to be there

• Tells which way water or wind moved in the past

• How can this be helpful?

Metamorphic RocksMetamorphic Rocks

• Popcorn is like metamorphic rocks. The heat and pressure of the microwave makes the kernels explode

Examples

• Limestone can be changed into marble which is used by builders and artist

• Shale turns into schist which can be used for jewelry and graphite

Metamorphic continueMetamorphic continue

• Rocks that go through metamorphic do not melt

• If it melts it would be an igneous rock

• Rocks change by how much heat and pressure is added

• Depending how far deep the rock is below the surface could effect how it changes

ChangesChanges

• One side could become flat because of pressure

• Recrystalization can occur

• Changes can occur over large distances or short distances

Foliated RocksFoliated Rocks

• Foliation develops when rocks are under pressure

• Foliation only occurs if the rock has more than one mineral