Download Chapter 4: Rocks and Their Transformations The Three Types of

Thai Christian School
Grade 6 English Program
SCIENCE – Home Study
Name : …………………………………………
Subject : Science
Grade : 6/
Date : November 2011
Number : ………………….....
Teacher : Miss Maggie Quinn
Parent Signature: …………….....
Instructions: Read and answer the questions.
Chapter 4: Rocks and Their Transformations
The rocks around us may be thousands or millions of years old. There are many types of
rocks. They come in various colors, hardness, and textures. The rocks you see around
you – the mountains and riverbeds, are all made of minerals. A rock may consist of two
or more minerals.
Minerals: are made of chemicals, either a single chemical or a few. All rocks are
made of minerals. Diamonds, quartz, feldspar and mica are examples of minerals
found in rocks.
Minerals in rocks are like the ingredients in a cookie. The cookie is the rock. The
flour, butter, chocolate and sugar are like the minerals that make up the rock.
Questions: Write True or False
1. The rocks around us are hundreds of years old. ____________
2. There are many types of rocks with different colors, hardness, and texture. ___________
3. Rocks are made up of one or more minerals. _____________
4. Rocks are made up of minerals, just like a chocolate chip cookie is made up of flour,
butter, chocolate and sugar. ____________
The Three Types of Rocks
Rocks can be put into three main groups based on the way they are formed.
I. Igneous Rocks
Created by magma
and lava.
II. Sedimentary Rocks III. Metamorphic Rocks
Created by compressed Created from other rocks
layers of sediment.
by heat and pressure.
I. Igneous rocks:
Igneous means fire in Greek. Igneous rocks are formed when magma cools and solidifies.
Magma is extremely hot liquid molten rock found deep in the Earth. Magma can be 700-1300
degrees Celsius. Once magma reaches the surface of the Earth it is called lava. Magma usually
comes out of the Earth as lava through volcanoes.
There are two types of igneous rocks. Intrusive and extrusive. Look at the
differences and similarities of these rocks.
Extrusive
Rock
Intrusive
Rock
All Igneous Rocks
Intrusive Rocks
Created when magma
cools slowly
underground and
solidifies into large
crystals.
Both
Created by magma
Extrusive Rocks
Created by volcanoes from
lava. Lava cools quickly
and forms rocks with small
crystals.
Do not have fossils
because they are
Example: Granite, very made of molten rock Example. Obsidian (looks
hard, solid rock, many
like black glass because it
mountains are made of
cooled very quickly) basalt,
granite. Doi Inthanon in
pumice, have holes, light.
Chaingmai is a granite
Basalt can be found in the
mountain
Phetchabun mountains
Questions: Complete the sentences.
1. Igneous rocks ____
(a) is liquid rock found deep inside Earth.
2. Magma ____
(b) are made of magma and have large crystals.
3. Lava ____
(c) are made of lava and have small crystals.
4. Intrusive igneous rocks ____
(d) are formed when magma cools and solidifies.
5. Extrusive igneous rocks ____
(e) comes out of volcanoes.
II. Sedimentary rocks
Sedimentary rocks are created by layers and layers of sediments.
Sediments - are the bits and pieces of rocks that have been broken down by
time, wind and water. These small pieces of rock are washed into rivers,
seas, and oceans and settle at the bottom of the water. Often minerals and
dead living things are also found in the sediments.
Over millions of years, layers after layers of sediments pile up and are compressed
by gravity, air and water pressure. The sediments loose water over time and they slowly
harden and become rocks. Most sedimentary rocks are formed in water.
Different rocks are made up of different sediments.
 Limestone – is mostly made up of shells or skeletons of marine animals like corals
and shellfish
 Conglomerate – is made of pebbles and sand
 Sandstone – made of sand, is usually layered
 Shale – or mudstone, is made up of clay or mud
 Gypsum – made up of sulphate minerals, formed by evaporating sea water
Sedimentary rocks usually look layered. The Grand Canyon in the US is a perfect
example. Sedimentary rocks may also contain fossils.
Fossils – are the preserved remains of animals or plants that were trapped as the
rocks were formed. can be a footprint, an animal shell, a piece of plant, an animal
bone, or any other ancient organism. The oldest fossils ever found are 4.5 billion
years old!
Questions: Write your answers.
1. What are these sedimentary rocks made up of?
a. Limestone: _____________________________________________________
b. Shale: _________________________________________________________
c. Conglomerate: __________________________________________________
2. What are sediments? _____________________________________________________
3. Where are most sedimentary rocks formed? ___________________________________
_______________________________________________________________________
III. Metamorphic rocks
Metamorphic rocks are created from igneous and sedimentary rocks that have
changed from very high heat and pressure to become new kinds of rocks.
This happens when rocks are pushed by mountains, volcanoes, or earthquakes. The
Earth's crust moves and presses the rocks very tightly together and creates high heat and
pressure.
Metamorphic rocks are very solid, shiny, and usually hard.
Examples:
Questions: Fill in the blanks.
1. Metamorphic rocks are created from __________________ and __________________
rocks.
2. Rocks are pushed by __________________, __________________, or
__________________ to form metamorphic rocks.
3. The rocks are changed by high __________________ and __________________.
4. Metamorphic rocks are usually very __________________, __________________, and
__________________.
Comparing Rocks
We can classify rocks by their characteristics, color, texture, or hardness.
Igneous Rocks
Sedimentary Rocks
Created by magma and
lava.
Do not have fossils
Not layered
Usually hard
Usually black or grey color
May have air pockets
Created by compressed
layers of sediment.
Contain fossils
Usually layered
May be hard or soft
Mostly brown or grey
Tend to break along layers
Metamorphic Rocks
Created from other rocks
by heat and pressure.
May have fossils
Flattened layers
Very hard
Many colors
Shiny
Review Questions: Write your answers.
1. Which type of rock is formed when molten rock cools and solidifies?
______________________
2. Which two types of rocks may contain fossils? _________________________________
3. Give two examples of igneous rocks. _________________________________________
4. Give two examples of metamorphic rocks. ____________________________________
5. What two factors change rocks into metamorphic rocks? _________________________
Finished! Good Job! Thank you!