It Rocks!Rocks and the
Rock Cycle
A rock is a mixture of minerals, rock fragments, volcanic glass, organic matter, or other natural materials.
What do you see in this sample of pink granite?
Just what are rocks?
What is the difference between a rock & a
mineral? Minerals are solid,
naturally occurring, inorganic, have a fixed composition and are made of one or more elements.
Rocks are made of one or more minerals.
Let’s Compare…
Must be inorganic
Made of elements or
compounds and must be
chemically bonded
Naturally occurring
Made of elements
Solid
Can be made of
lava/ magma
Have crystals
Can be formed
from solutions
Can be made from
organic materialsMixtures made of minerals
Can be man made
Rock
Classifications Igneous
Sedimentary
Metamorphic
Igneous Rock
Igneous is Greek and means ‘born of fire’
Igneous rock forms when magma, hot molten rock, cools and hardens
Igneous rock can be intrusive or extrusive
Intrusive Igneous
Rock Formed from
magma cooled below the Earth’s surface
Cools very slowly Forms mineral
grains large enough to see with the unaided eye
Extrusive Igneous
Rock Formed as lava cools
on the surface of the Earth
Cools quickly Exposed to air and
water which can result in holes in the rock material
Forms very fine (small) mineral grains.
Extrusive Igneous
Rock Includes Volcanic
Glass Lave cools very
very quickly Few or no
minerals grains form
Atoms are not arranged in an orderly pattern
Sedimentary Rock
Forms when sediments are pressed and cemented together
Forms when minerals form from solutions
Often form layers If undisturbed by
nature, the oldest and first layer is the bottom layer
Sedimentary Rock
Sediments are loose rock fragments, minerals grains, and bits of shell that have been moved by the wind, water, ice or gravity.
Sediments form from the processes of weathering and erosion
Compaction – occurs when pressure on the uppers layers of the sedimentary rock pushes down on the lower layers.
Cementation – the process by which water and dissolved minerals move through open spaces and form a glue-like substance
Metamorphic Rock
Metamorphosis – to change
Rocks that have changed their chemical composition due to the presence of extreme heat and pressure or
Rocks that have been subjected to hot watery fluids
Metamorphic Rock
Can form from igneous, sedimentary or other metamorphic rock
Can be foliated - mineral grains appear in parallel layers
Can be nonfoliated – mineral grains do not align in layers
To show how rocks slowly change through time, scientists have created a model called the rock cycle.
It shows the processes that form and change rocks.
The rock cycle shows the three classifications of rock— igneous, metamorphic, and sedimentary—and the processes that form them.
The What?...The Rock Cycle
The Rock Cycle explains how Rocks and Natural Processes
are relatedweathering
melting
pres
sure
, hea
t
Sedimentary Metamorphic
Igneous
Law of conservation of matter
states that matter cannot be created or destroyed.
The changes that take place in the rock cycle never destroy or create matter.
The elements are just redistributed in other forms.
What is the law(principle) of conservation of
matter?
Let’s Have Some
Fun!!
http://tinyurl.com/yzvw4k8
http://mrhardy.wikispaces.com/Rock+Cycle.swf
http://tinyurl.com/8g2fr6f (Study Jams – really great site)
More Fun with the Rock Cycle
Prepared just for YOU, my 6th Grade Earth Science classes!
Ms. HoustonAustin Road Middle School