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KIDS: Our World!
EVAN: You know Globey, here on Earth we have 3 basic
types of rocks: Igneous, sedimentary, and metamorphic rocks.
Scientists classify the rocks by the way they were made.
Igneous rocks are formed when lava from a volcano cools and hardens.
Igneous rocks are also formed when magma cools below Earth's surface.
Sedimentary rocks are formed when the elements wear rocks
down into tiny particles of dust, sand, and soil.
Wind and water help move these particles around
and deposits them into layers.
As time passes, these layers are cemented together and harden into new rocks.
Metamorphic rocks form when sedimentary or igneous rocks
change after being exposed to extreme heat or pressure without melting.
As conditions on Earth change, rocks may change from one type to another.
Sedimentary rocks can change into metamorphic rocks or,
if they melt, into igneous rocks.
Igneous rocks can change into sedimentary or metamorphic rocks.
And metamorphic rocks can change into sedimentary or igneous rocks.
Scientists call these changes the rock cycle.
But NASA scientists want to study rocks from other places,
like the moon and Mars as well.
They want to see if other rocks are like the rocks found here on Earth.
By studying rocks from the moon or Mars, scientists can
learn a lot about how the land was formed and how it
has changed over time - the history of the rocks.
They can tell how the geologic history of another
planet compares to the geologic history of Earth.
During the Apollo missions to the moon 40 years ago,
astronauts brought back dozens of rock samples from the moon's surface.
Today scientists from all over the world have a chance to study these lunar rocks.
And by studying the rocks, scientists have discovered
that the rocks on the moon can be classified into 3 basic types, too.
The first is lunar basalt. This type of moon rock is
similar to volcanic lava found on earth.
It starts on the moon in a lava state and then cools to form a hard rock.
The second type of moon rock is called anorthosite which
forms from the cooling of a large ocean of magma shortly after the Moon was formed.
Lunar breccia is the third type of rock.
Light areas of the breccias are either pieces of
anorthosite or unmelted rock.
The dark areas are either basalt or melted rocks
from meteoroids hitting the surface
Thanks to the lunar samples brought back by NASA astronauts,
scientists finally know what the moon is made of.
[Globey sfx] No Globey...it's NOT CHEESE!
But scientists aren't the only ones who get to view the lunar samples.
The Lunar Sample Laboratory Facility at NASA's
Johnson Space Center also lends moon rocks out to
educators and museums around the world.
Some of the samples have been preserved in round discs of clear Lucite.
People who have had special training take those samples
to classrooms and museums so many other people can see
what these special lunar rocks look like.
A few museums have their own moon rock on display.
So you can visit a museum and see a real moon rock in person!
The Lunar rock samples brought back from the moon
40 years ago still provide meaningful data
to scientists all over the world.
They continue to teach us how the rock cycle on the moon is
similar in many ways to how rocks change on earth...or even other planets.
So now you know how rocks grow and change beneath our feet...
thanks to the rock cycle!
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KIDS: Our World!