Script for
Elements, Minerals and Rocks
This slideshow is designed for upper primary, but can be used with second and third. It has students develop observation skills to help with identification.
Slide 1.
This is a picture of a quartz cluster. Tell students today is a lesson on the
rock cycle. They will learn that rocks
and minerals give you clues on how they were created.
The video shows how crystals grows over time.
The crystals are not quartz (they are alum), but basically show how the
elements are combining to form a substance.
Most quartz precipitates out of solution whether in water or molten rock.
·
Minerals make up rocks. (Some rocks have
big minerals, but many you would need to look under a microscope (called a
petrographic microscope)
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Rocks
are formed in three environments
1. Igneous rocks
need to be melted first; for younger students may want to use “fire rocks.”
2. Sedimentary
rocks are made of smaller pieces that are cemented together; they are usually
associated with water.
3. Metamorphic
rocks need to be squished under heat and pressure by Mother Nature. (Older
students: could use pressure by plate movements.)
Not hot enough to melt (or would be
igneous). Minerals are sometimes flat
and shiny, so also can be called “Rhinestone rocks.”
·
All
matter known on Earth is found on this chart.
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Younger students ask, “Are you made of elements?
They may have to think about the question and even say “No.”
Ask them if they have water in their
body? The components are water or H2O (many young students have heard
that term) – hydrogen and oxygen.
Hydrogen’s symbol is H. Ask
students to find the number…. Which is 1.
Then ask them to guess what the symbol for oxygen is “O” and the number
is 8.
·
Ask
students to look at the periodic table.
Do they see a pattern with the numbers?
Do they increase in one direction?
(Horizontal) It took scientists a long time to figure out the elements
and put them in this order.
·
Older
students may know that the atomic number represents the number of protons, which
is unique for every element. This is a good opportunity to review Atomic number,
Atomic weight (mass of all isotopes of an element), and Atomic symbol.
·
Some
atomic symbols do not look anything like the names we use for the elements. This
is because many of the scientific names for the elements are rooted in Latin and
Greek
Slide 4.
Native
Copper
·
Shows native copper and uses. Tell
the students copper can be found in an almost pure form in parts of the earth’s
crust. Copper can also be found mixed with other elements. When it is found in
an almost pure form it is referred to as
native copper. Native copper is a native mineral. When a miner finds a gold
or silver nugget, that nugget is also a native element. Native minerals are
naturally occurring elements in their pure form.
·
Mining of copper is when you take rock that is enriched with the mineral and
extract it mainly through crushing the rock and removing the mineral you want
(either physical or chemical). In
the video from an Arizonia mine, students can get an idea of the mass amount of
rock needed.
Slide 5.
Halite
·
A compound is a molecule made of atoms of two or more different elements.
Look at each slide and discuss characteristics for each mineral.
·
Halite has a cubic crystal structure.
Look at the formula for halite:
Na-sodium, Cl-chlorine. Na is
a violently reactive substance that can explode in water and Cl is a poisonous
gas that can be lethal when inhaled but when combined in a compound they become
sodium-chloride. Tell them they all have sodium chloride at home on the dining
room table or in the kitchen and they use it to make food taste good. They
should be able to guess that sodium-chloride is table salt.
Slide 6.
Calcite
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The shape as a rhombus, a
three-dimensional parallelogram.
Also, point out the characteristic of
double refraction. Look at the
formula as before (Ca-calcium, C-carbon, and O-oxygen).
Calcite is important mineral used in making concrete.
Cement mixture includes calcite that helps it make concrete a hard
“person made” rock. Very
important to society to make buildings.
Slide 7.
Quartz
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Display the outer surface of the amethyst geode and ask if it is impressive.
Show the crystals within for entertainment factor. Quartz-made up of Si-silicon
and O-oxygen. They will recall the elements from the previous activity or remind
them! Quartz has a
Hexagonal shaped crystal and it comes in many different colors
(lower activity 2). Quartz is a very
hard mineral. Older/advanced students, pure silicone is made by heating up
quartz sand to the point where all of the oxygen escapes/burns off.
·
To get the silicon, the oxygen is removed by mixing it with
carbon and heating it in an electric arc furnace to temperatures beyond 2,000
degrees C. At those temperatures the carbon reacts with the oxygen, becoming
carbon dioxide and leaving pure silicon in the bottom of the furnace. That
silicon is then treated with oxygen to remove impurities such as calcium or
aluminum, leaving what's known as metallurgical grade silicon. That's up to 99%
pure.
·
Video shows how many of these crystals are found in the famous Arkansas mines.
Notice they are not really “pretty” when you find them and they have to
be cleaned up to look like the minerals you purchase in a store.
Slide 8.
Pyrite, Talc, Magnetite
This slide is about different mineral properties (shape, hardness, magnetism).
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Pyrite: Fe-iron and Sulfur-S. They
should remember these elements from previous activity. Have a conversation about
the 49er’s (not the football team!)
and where the idea of “Fool’s Gold” came from. Unknowing
people came to California in 1849 looking for gold.
Scrupulous “gold experts” would get unsuspecting people to pay them money
to find the rivers lined with gold.
They would go to rivers with pyrite in it, and then the people would pay them.
Then when the people went to the bank, they were told they had “Fool’s
Gold.” An early version of a
scam. Gold is much heavier and yellow in
color while pyrite is brassy.
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Talc: Point out the different
elements that make up talc. This element is composed of several elements. It is
also very soft. Ask them if they
have heard any product that has the name in it.
Talcum power or Baby power.
Yes, a mineral is put on a baby’s butt.
Key characteristic is that it can be scratched with a fingernail.
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Magnetite-why do you think it is called “magnetite?”
It is magnetic, another characteristic of some minerals.
Slide 9.
Minerals make up
rocks
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If you look at a rock up close or under a microscope you will be able to see
some of the minerals we have identified today. Can show/pass around the sample
of granite. Point out the clear quartz, the white/grey feldspar and the black
micas/hornblende.
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Picture of Yosemite and close up is components of minerals that makes up the
rocks. Notice white is quartz, gray
feldspar, black is hornblende or mica.
Slide 10.
Rocks are
made in three environments.
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The environments are sedimentary (water), igneous (fire), and metamorphic
(squished). Click each type of rock to go
through each. Depending on grade will
depend how deep you go into each of the sections.
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Igneous
10 A1
- These slides help explain plutonic and volcanic rocks.
Go over the animation of magma and lava
when they are forming; plutonic and volcanic rocks when they are cooled; and
together they are called igneous rocks.
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Igneous 10 A2.
Show the video of a Hawaiian eruption.
Ask which type of igneous rocks could form this way (pumice, obsidian).
The red lava is not cooled, but the
black rock has already cooled down.
Some of it will be obsidian which cools very quickly.
Notice lava being spurted upward, when it comes down it may be a Volcanic
Bomb.
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Igneous 10 A3.
Show the
“rocks created from volcanoes”. For advanced/ upper level you can point out
where pumice, obsidian and basalt form in relation to each other, and the speed
at which they form. Obsidian and pumice cool faster than basalt.
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Igneous 10 A4.
Show the
“High silica” slide. Explain that the type of igneous rock depends on how
much of certain minerals are within them. Silica (quartz) is light colored and
will produce light colored igneous rocks, such as rhyolite (volcanic) and
granite (plutonic). If students are very advanced you can explain that rhyolite
and granite have the same mineral composition, but look different because one is
volcanic and the other is plutonic.
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Igneous 10 A5.
Show the
“Low silica” slide. Dark colored igneous rocks do not have quartz, instead
they have dark colored minerals. Igneous rocks composed of dark-
colored minerals include basalt (volcanic) and gabbro (plutonic).
Sedimentary (click on picture to go
through different slides)
Customize material depending on knowledge and grade of students.
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Sedimentary 10 B1.
Sedimentary rocks are those which are composed of sediment. Broken up pieces of
other rocks. The pieces of broken up rocks are usually transported by water,
which is why these can be called “water rocks:”. The age/level of the students
determines how much detail to give in the next slides.
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Sedimentary 10 B2.
The sediments are transported and over time turn into rocks. The type of rock
produced will depend on how big the pieces of broken up rock were. For
advanced/upper level can explain that large sediments, like gravel will produce
a conglomerate. Smaller sediments,
like sand, will produce a sandstone.
Even smaller sediments, like silt will produce
siltstone, and mud/clay will produce
a shale.
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Sedimentary 10 B3.
Over time the sediments are
compressed. That pressure compacts the sediment, and squeezes all of the water
out from between the little particles. The sediments are cemented together,
often by calcite or quartz.
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Sedimentary 10 B4.
Another type of sedimentary rocks are chemical sedimentary rocks. Instead of
being made up of small particles of other rocks, these rocks precipitate or
“grow”. Water evaporates, and the minerals that are in that water get left
behind. Can show the students the large salt crystals.
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Sedimentary 10 B5.
Sedimentary rocks can preserve structures. Structures that can be preserved
include ripple marks (pictured). These structures help scientists determine what
kind of environment the rock formed in. Fossils
are also only found in sedimentary rocks.
The animation just shows how you can identify ripple marks as they deposit a
specific shape
Metamorphic
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Metamorphic 10 C1.
Metamorphic rocks are igneous and
sedimentary (also other metamorphic rocks) that have undergone a change, or a
“metamorphosis”. The change is the result of heat and/or pressure. The heat can
come from being close to a magma chamber and the pressure can come from being
squished against/under other rocks. The age/level of the students determines how
much detail to give in the next slides.
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Metamorphic 10 C2.
Gneiss is an example of a metamorphic
rock. It has been squished by a lot of pressure. When a rock gets squished the
minerals rearrange themselves. In a Gneiss the light minerals (quartz and
feldspar) separate from the dark minerals (biotite and hornblende). This makes
stripes/bands.
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Metamorphic 10 C3.
A schist has also been squished, but not as much as a gneiss. This is a
microscope image of a schist. You can see the minerals have been rearranged.
They are now foliated, all of the mica minerals have rotated to point the same
direction. When you look at a schist from the side it can have layers that look
like pages from a book. These are layers of foliated minerals.
A quartzite is made
out of what mineral? (Quartz). A quartzite has also been squished, but unlike
the schist and gneiss it is not foliated. Instead of the minerals rotating, they
are just squished together. This forms a granular texture. Rocks composed of
quartz and carbonate will not become foliated. The quartz and calcite crystals
are the shape and strength in all directions, so the crystals cannot rotate.
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Metamorphic 10 C4.
Heat can also cause a rock to be metamorphosed. The type of metamorphic rock
will depend on how much it was heated. A rock that is very close to the heat
(magma body) will have different minerals than one that is further away from the
heat. High heat minerals include garnet and diopside, lower heat minerals
include chlorite and serpentine. The
rock serpentinite is made up of the mineral serpentine.
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The rock
cycle includes all three of these environments and they are all connected. Rocks
change over time.
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You
never loose rocks, but they can change depending on the evolution of the area.
Little ones just need to know they change, while you might want to review
with older students.