Chapter 9

Rocks and Minerals6th Grade Science

Minerals

• ___________ - a natural, non-living solid with a definite chemical structure.

• Earth’s crust contains more than _________ minerals – only two dozen are common.

• Examples: diamond, quartz, emerald copper• Minerals are made up of ______.• Particles of _______ are arranged in a

particular repeating pattern.

Mineral

4,000 kinds

crystals

crystals

Crystals

• _______ form when minerals are made in nature

• Each type of mineral has its own unique chemical __________.

• Differences in minerals result from the way that particles are arranged.

• Brass – Copper + Zinc –____________because it does not occur naturally

Not a mineral

structure

Mineral

Identifying Minerals

• _________• _________• ____________• __________• ___________

hardness

Streak color

Shape of crystals

cleavage

Luster

Identifying Minerals

• Minerals are identified by their ____________• _______________ - a scale to measure

hardness of a mineral • The range of the harness scale is from 1

(_______) to 10 (______)• Talc has a harness of __ / diamond is a _____• ________ - refers to how difficult it is to

scratch its surface

characteristics

Moh’s hardness scale

hardness

Softest Hardest

1 10

Other Mineral Characteristics

• _______ - a mineral may have different crystals depending on the kinds of materials that make up its ______.

• The color of a mineral can be seen in its ______.

• A mineral can also be identified by the ______ of its crystals.

• _______ - minerals show particular patterns when they are broken along flat planes.

Color

crystals

streak

shape

Cleavage

Luster

• ______ - the appearance of a mineral in reflected light.

• A mineral may appear:– __________– __________– __________– __________– __________

Luster

Metallic

NonmetallicGreasy

Glassy

Waxy

Value of Minerals

• Some minerals are ____ which makes them very valuable

• Some minerals are valuable because they are ______________ - scientists have tried to find ways to reuse minerals or replace them with less expensive materials.

• Aluminum and tin can be ________• Synthetic forms of gemstones = cubic zirconia

rare

Natural Resources

recycled

Assessment

• Page 249 questions 1 and 2

Rocks

• _____ - a solid, natural material made up of one or more minerals

• ___________ - as time passes, rock break down, and the minerals in them are recycled – pattern of change

• The rock cycle takes place over ________ of years.

• There are three types of rocks: __________, __________, and __________

rock

Rock cycle

millions

sedimentaryigneous metamorphic

Sedimentary Rock

• ______________ - made from pieces of rocks and minerals

• Sedimentary rock forms in ________ - the oldest rock at the bottom and the newest rock on top.

• Sedimentary rock is like a “_________” - past events captured in each layer.

• _____ - remains of once living animals or plants

Sedimentary rock

layers

History book

fossils

Sedimentary Rock Continued

• Fossils are ONLY found in _____________• Example of sedimentary rock = ________• Limestone is made from _________________

or from dissolved __________ that settle out of seawater.

Sedimentary rock

limestone

Shells of tiny sea animals

minerals

Igneous Rock

• __________ - forms from magma – molten rock inside of the earth that cools and hardens

• Some igneous rock forms ______________ and is only exposed after rocks above have worn away

• Other igneous rocks form when _____ cools at the Earth’s surface

• When lava cools fast - _______________• When lava cools slowly - _______________

Igneous rock

Below Earth’s surface

lava

Fine-ground rocks form

Coarse-grained rock

Metamorphic Rock

• _____________ - forms when heat, pressure, or chemical reactions change one type of rock into another type of rock.

• Metamorphic rock is made from ___________ or _________.

• Example: ______ is a metamorphic rock made from________ (sedimentary rock)

Metamorphic rock

Sedimentary rockIgneous rock

marblelimestone

Compare and Contrast

• How are the three types of rocks similar and different?

Clues to the Past

• Scientists can tell a great deal about Earth’s history by looking at _____.

• ______________ - scientists look at the layers of sedimentary rock and learn about the relative age of each layer and the minerals found in it.

• Relative dating allows scientists to place past events in ____________

rocks

Relative dating

Sequential order

Fossils

• ________ - can form when an organisms is buried in soft mud or when parts of the organisms do not rot away.

• Burrows and footprints can also be fossilized• Many fossils were made by animals that are

now _____ - helps scientists determine the rocks age.

• __________ - a fossil of marine animals known as corals

fossils

extinct

Peoskey Stone

Assessment

• How can rocks help scientists learn about the past?

• What are trilobites and when were they on Earth?

Soil

• ____ - made of weathered rock, air, water, and the remains of living things.

• __________ - process of breaking down rocks through physical factors such as _____, _________, _______ or__________________.

• ________ = non-living parts of the soil• As rock breaks down small pieces collect on

the surface

soil

weathering

frostdrought Changes in temperaturerainwater

inorganic

Soil Formation

• _______ and _______ are plants that help break down rock.

• When rocks are broken down _______are released

• ___________ - dead or decaying matter such as bacteria, fungi, animals and plants.

• ______ - dark colored organic matter formed from decayed plant and animal remains- _______________________

mosses lichens

minerals

Organic matter

humus

Rich in nutrients needed by plants

Layers of Soil

• Soils form in _____ layers• _________- a vertical cross section of the soil

and rock underneath• ________ - first layer of soil, mixture of small

rock pieces, humus, and other organic matter– Most living things are found in the _______– Loose _____________ often covers the topsoil– Rainwater carries minerals from the topsoil to the

2nd layer of soil.

three

Soil profile

topsoil

topsoilOrganic matter

Subsoil / Parent Rock Layers

• _______ - less organic matter than topsoil, lighter in color.

• _________ penetrate the subsoil through rainwater and accumulate

• _________ - third layer, very little organic matter found in this layer

subsoil

mineral

Parent rock

Kinds of Soils

• ________ - fine grained and hold water – these soils can become waterlogged

• _________ - medium sized grains – better drainage than clay soils

• __________ - large-grained, do not retain water

• Most soils are a mixture• ______ - silt and sand in roughly _____ parts

Clay soils

Silt soils

Sandy soils

loam equal

Factors That Affect Soil

• ________ - most important factor that determines the type of soil that is formed

• Climate affects _________ - increased rainfall, warm temperatures, frost-thaw etc.

• __________ - minerals in the rocks affect the characteristics of the soil – example: reddish colored soil indicates iron-rich minerals

• __________ - mix the soil and breakdown organic matter

climate

weathering

Kinds of rock

earthworms

Soils Continued

• Soil color is affected by the amount of __________ in the soil.

• Soils with more organic matter are ______• ___________ - affects soil formation because

of slope and erosion• Mountains have thin layers of ______• Land that is flat has a _________ of topsoil

because of minimal erosion

Organic matter

darker

Shape of land

topsoil

Thick layer

Assessment

• Write an advertisement for an ideal soil for growing plants.