rocks and soil around us

Students know how to compare the physical properties of different kinds of rocks and know that rock is composed of different combinations of minerals.. Students know smaller rocks co

Genre Comprehension Skill Text Features Science Content

Nonfi ction Draw Conclusions • Captions

• Labels

• Glossary

Natural Resources

Scott Foresman Science 2.6

Standards Preview

Standard Set 3 Earth Sciences

3 Earth is made of materials that

have distinct properties and provide

resources for human activities As the

basis for understanding this concept:

3.a Students know how to compare

the physical properties of different

kinds of rocks and know that rock is

composed of different combinations of

minerals

3.b Students know smaller rocks come

from the breakage and weathering of

larger rocks.

3.c Students know that soil is made

partly from weathered rock and partly from organic materials and that soils differ in their color, texture, capacity

to retain water, and ability to support the growth of many kinds of plants.

3.e Students know rock, water, plants,

and soil provide many resources, including food, fuel, and building materials, that humans use.

ISBN 0-328-23511-3

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Earth Sciences

by Mary Beth Spann

fuel

luster

minerals

natural resources

rock

soil

weathering

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publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions.

Unless otherwise acknowledged, all photographs are the copyright of Dorling Kindersley, a division of Pearson.

ISBN: 0-328-23511-3

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Rocks and Soil

Around Us

by Mary Beth Spann

Getting to Know

Rocks and Minerals

Rocks are found all over the Earth They can

be found at the park or in a fi eld They can be

found at the bottom of the ocean A rock is the

hard, solid part of Earth that is not soil or metal

Rocks can have amazing shapes!

3

Different rocks have different colors

Different rocks feel different Some are smooth and others are rough

Some rocks are small and light You can hold these rocks in your hand Other rocks are very large Rocks can be the size of an elephant!

Can you tell how these two rocks are different?

Many Minerals

Minerals are what rocks are made up of

Minerals are nonliving materials that come

from Earth Diamond and copper are minerals

Diamonds are used to make rings and other

forms of jewelry Wires, coins, and many other

things are made from copper

Diamond

Copper penny

Copper

5

Most rocks have more than one mineral inside of them Gabbro is made up of the minerals feldspar and pyroxene Gabbro forms deep beneath Earth’s surface It makes up much

of the ocean fl oor

Gabbro contains pyroxene and feldspar.

Minerals Have Properties

We learn more about minerals by studying

their properties All minerals have properties

A property is something about an object that

you can observe Minerals can be hard or soft

Hardness is one property of minerals

Color is a property of minerals too Garnet

can be red Opal can be blue

Garnet

Opal

7

Some minerals are shiny Other minerals are

dull Luster is the property of how shiny or dull

a mineral is Quartz can have a glassy luster

Galena’s luster is shiny

Quartz

Galena

Rocks and

Weathering

A rock’s size, shape, and color can be

changed by weathering Weathering is the

breaking apart and changing of rocks

Weathering can change big boulders into

smaller rocks Weathering can change very

small rocks into sand

Weathering turns big rocks into

smaller rocks It turns smaller

rocks into gravel and sand.

9

Water and temperature changes can cause weathering Water weathers a rock by getting inside its cracks The water can freeze into ice

The ice can then cause the rock to break apart

Plants can also cause weathering Sometimes plant roots grow into cracks in a rock The

growing roots can break the rock apart

The roots of plants can weather rocks

More Causes of Weathering

Look at the inside of the cave Water in

the ground dissolved rock Then the rock was

washed away by the water Dripping water

made the shapes on the cave’s fl oor It also

made the shapes on the cave’s roof The shapes

join to make columns

Dripping water made the

shapes in this cave

11

Some rocks have iron in them If these rocks get wet, the iron mixes with air They mix

together to make rust The rust gives the rocks

a reddish brown color It causes the rocks to weaken It might make them break apart

Rust has made this rock reddish brown.

All About Soil

Soil is the top layer of Earth It is where

plants grow

Weathering turns big rocks into small rocks

It also turns small rocks into sand Weathering

also turns small rocks into soil

Soil has rocks of

different sizes in it

13

Soil is full of weathered rock and other things It has pieces of leaves and twigs It also has the remains of living things that have died

Animals dig in soil This can change the soil

Animals loosen and mix the soil by digging in it

These rabbits change the soil

by loosening and mixing it

Many Kinds of Soil

There are different kinds of soil Different

plants grow best in different kinds of soil

Sandy soil is bad for most plants It does not

hold water well Sandy soil can be found in

deserts It is also found near oceans and lakes

Sandy soil is dry and very loose

15

Clay soil holds water well But some plants

do not grow well in it Clay soil often has a red color This color can come from iron in the soil

Most plants grow best in loam Loam holds water well This helps plants get the water they need Then the plants can grow

Clay is soft and sticky

It also feels smooth.

Loam is good for growing most plants.

Natural Resources

We use resources every day Natural

resources are useful materials that come from

Earth Soil and water are natural resources

Rocks and plants are natural resources too

How many natural

resources can you see here?

17

Natural resources give us things we need

We use natural resources for food and clothing

We also use them for shelter and fuel

Many of the things we build contain rocks

We get food by growing plants in the soil Trees are plants that can also be used to build things

Some plants can even be used for fuel

The water and food

on this farm are natural resources.

This dam was built with natural resources.

More Natural Resources

Rocks, soil, water, and plants are natural

resources We use rocks to build things

We mix sand, cement, and water to make

concrete From concrete we make sidewalks,

bridges, and buildings

Parts of this bridge were made from rocks.

19

Wood is a natural resource Oil, gas, and coal are also natural resources We get fuel

from these natural resources Fuel is anything

that is burned to make heat or power Oil, gas, and coal come from plants and animals These plants and animals lived long ago

A car uses gas for fuel

Gas comes from plants that lived long ago.

fuel anything that is burned

to make heat or power

luster how shiny or dull a

mineral is

minerals nonliving materials that

come from Earth

natural resources useful materials that

come from Earth

rock the hard, solid part of

Earth that is not soil or metal

soil the top layer of Earth

weathering the breaking apart and

changing of rocks

Glossary What did you learn?

1 What are the three different kinds of soil?

2 What two minerals make up gabbro?

3 You learned many different things about natural resources while reading this book Write a couple of sentences about natural resources Make sure

to group related ideas together as you write

4 Draw Conclusions If you come across a

soil that is very dry and has few plants growing in it, what might you conclude?