Rocks Rock!
What are rocks?
• Rocks are always
underneath you. Even on
water, there is rock
beneath you. Rocks are
made of minerals.
Sometimes you see
specks of different colors
in a rock. Sometimes you
see shiny specks. These
different specks are the
minerals in a rock.
What are sedimentary rocks?
• Millions of years ago, wind blew
dust and sand into the lakes and
oceans. The dust and sand settled
to the bottom in layers called
sediment. Seashells formed layers
of sediment, too. Over time, the
layers hardened into sedimentary
rock we see today. Sedimentary
rock comes from a word that
means “ to settle.” Limestone,
shale, and sandstone are
sedimentary rocks. You can often
find fossils in sedimentary rocks.
What are igneous rocks?
• Melted rock can push through
cracks in the Earth’s crust.
When the melted rock cools
and hardens, it is called
igneous rock. Sometimes it
cools inside the earth and
other times it becomes lava
and cools outside the earth.
Igneous comes from a word
that means fire. Granite,
obsidian, and pumice are
igneous rocks.
What are metamorphic rocks?
• The deeper inside the crust
of the earth, the hotter it
gets. The rocks get harder,
too. These are rocks that
were changed from one
kind to another kind due to
heat, time, and pressure.
Metamorphic rocks are
rocks that have changed.
Limestone changes to
marble. Shale changes to
slate. Sandstone changes to
quartzite.
What are the layers of the earth?
• Under the earth’s crust
there are pockets of
melted rock. Below this
is the mantle, made of
hot, melted rock called
magma. The outer
core is liquid metal
and the very center
of the earth, the
inner core, is a ball of
solid metal!
What is a volcano?
•
A volcano is an opening in the earth’s crust
where melted rock can flow out. Volcanoes
come in different shapes. This is how
volcano is formed. Extreme heat inside the
earth melts rocks, and magma is formed. The
melting rock produces gases, which mix with
the magma. The gas-filled magma begins to
rise. Pressure slowly builds as the magma
pushes against surrounding rock. The magma
is so hot that it melts some of the
surrounding rocks along the way, forming a
conduit, a tube-like passageway. The magma
travels through the conduit until it blasts an
opening, called a vent, through a weak area
of the earth’s surface. The gas is released,
and the magma flows out of the vent as lava.
The lava spills out onto the earth’s surface. It
eventually cools and hardens into igneous
rock.
What are the layers of soil?
•
The deepest layer is called the
substratum, or bedrock. Large rocks,
sometimes broken up by longer tree
roots, can be found here. Igneous
rocks like granite and basalt can be
formed here and metamorphic rocks
like slate and marble can melt into
magma. The middle layer is called the
subsoil. Here you will find smaller
rocks being broken up and rocks
changing as they go through their
rock cycle. Animals hibernate in the
subsoil. A sedimentary rock like
sandstone or shale may become
metamorphic because of the
pressure above. The top layer of soil
is called topsoil. It is the richest soil
because it is made of humus, or
decaying plants and animals. Topsoil
can easily be eroded away.
The End!
• We hope you
enjoyed our slide
show about
GEOLOGY! We had
fun making it and
learning at the
same time!