8th Grade Midterm Topics 2011
1. Geology
a. Rocks & Minerals
i. Minerals
1. What are the 5 characteristics of minerals?
a. Inorganic, CANNOT be made from anything that is or was
living
b. Solid
c. Definite Chemical Composition (Fixed Composition)– The
contents of a mineral is always fixed and do not change.
d. Naturally Occurring – NOT man-made
e. Crystalline Structure – The atoms of the mineral are
arranged in a repeating pattern.
2. What are the physical properties of minerals?
a. Explain why a particular property is useful to people?
i. What is luster? – Luster describes the way light
reflects off the surface of a mineral.
1. What are the different types of luster? –
Metallic, vitreous (a.k.a. glassy), pearly, silky,
or dull.
ii. What is density? – Density describes how much
matter is in a given volume (space).
1. What is the formula for density? D = m/v
iii. What is color? – Color is determined by the chemical
composition of a mineral.
iv. What is streak? The color of powder created when
rubbing a mineral across a surface.
v. What is cleavage? How a mineral breaks along a flat
plane
vi. What is crystal structure? A unique arrangement of
atoms or molecules in a crystalline liquid or solid.
vii. What is hardness? Hardness is a minerals ability to
resist scratching.
viii. What is conductivity? The measure of how well
energy is transferred through a mineral such as
electrical or thermal (heat)
3. Know examples of minerals.
a. Especially the examples that are from your Minerals notes
4. What are silicates? – Silicates are minerals that contain silicon
dioxide.
a. What does felsic mean?
i. Felsic minerals are silicates that contain high
amounts of silicon dioxide. These minerals are light
colored or colorless.
b. What does mafic mean?
i. Mafic minerals are silicates that contain low amounts
of silicon dioxide. These minerals are dark colored.
5. Formation of Minerals
a. What are ways that minerals can form?
i. From molten rock:
1. What are the 2 types of molten rock? - Magma
and lava are the 2 types of molten rock.
2. How are they different? - Magma is located
under ground. Lava is located above the
Earth’s surface.
3. How do minerals formed from magma differ
from those formed from lava? – Minerals
formed from magma are formed below the
Earth’s surface and have large crystals.
Minerals formed from lava are formed above
the Earth’s surface and have small crystals.
ii. From Solution: Think about how salt is collected from
the oceans and seas.
1. What is a solution? - A solution is a
homogenous mixture of more than one
substance.
2. What does homogenous mean? – Homogenous
means the mixture looks like one substance.
3. What are examples of solutions? – Examples of
solutions are ocean water, Kool-Aid, and air.
4. Explain how a mineral can form from a
solution. – A mineral can form from a solution
when the liquid of the solution evaporates.
5. What is an example of a mineral that is formed
from a solution? – Salt is a mineral that is
formed from solution.
iii. From Precipitate:
1. What is a precipitate? – A precipitate is a solid
that is formed from a chemical reaction.
2. Explain how a mineral can form from a
precipitate. (Think back to the Growing
Crystals Lab) - During the Growing Crystals
lab, we raised the temperature of the solution
(added thermal energy), so we could dissolve
more salt/copper sulfate into the liquid.
When the solution cools back down (loses
thermal energy), a precipitate forms and
crystalizes.
3. What are stalactites? – Stalactites are mineral
deposits that are shaped like icicles and hang
from the roof or wall of a cave. They form
from precipitation.
4. What are stalagmites? – Stalagmites are
mineral deposits that are like stalactites, but
point upward from a cave floor. They form
from precipitation.
ii. Rocks
1. What is the definition of a rock? - A rock is a solid that can be
composed of minerals, pieces of other rocks, and organic material
(plant & animal matter).
2. The 3 Types of Rocks
a. Igneous Rocks
i. What are Igneous Rocks?
1. How are they formed? – Igneous rocks are
formed from molten rock that has cooled and
solidified.
ii. Know examples of Igneous Rocks
iii. What are Intrusive Igneous Rocks? – Intrusive igneous
rocks are igneous rocks that are formed from magma,
below the Earth’s surface. These rocks have large
crystals.
1. Examples?
2. Granite, diorite, pegmatite
iv. What are Extrusive Igneous Rocks? - Extrusive
igneous rocks are formed from above the
Earth’s surface by lava and have small
crystals
1. Examples? - Obsidian, rhyolite
b. Sedimentary Rocks
i. What are Sedimentary Rocks? – Sedimentary rocks
are rocks that form from the accumulation of rocks,
minerals, or the remains of plants and animals (these
are sediments).
ii. How are they formed? – These rocks are formed from
eroded materials and lithification.
iii. What is lithification?
1. What are the steps of lithification? – The first
step of lithification is compaction. This is the
process of sediments accumulating over time
and squeezing closely together. The second
step is cementation, which is the process of
fusing the sediments together.
iv. What are clastic sedimentary rocks? – Clastic
sedimentary rocks are formed from rock and mineral
fragments.
1. Examples? – Breccia, sandstone, shale
v. What are biologic sedimentary rocks? – Biologic
sedimentary rocks are formed from organic remains.
1. Examples? – Coal, limestone
vi. What are chemical sedimentary rocks? – Chemical
sedimentary rocks form from chemical reactions, like
precipitation (think back to minerals).
1. Examples? – Rock salt
c. Metamorphic Rocks
i. What are Metamorphic Rocks? – Metamorphic rocks
are formed when an igneous, sedimentary, or
metamorphic rock changes into another rock.
1. How are they formed? – Metamorphism
happens when a rock comes into contact with
very high heat and/or high pressure.
ii. What is the major characteristic of foliated
metamorphic rocks? – Foliated metamorphic rocks
have banded layers.
iii. Examples of metamorphic rocks are gneiss, slate,
schist, and marble.
3. The Rock Cycle
a. What is the rock cycle? – The rock cycle is the process by
which a rock changes into another type of rock.
b. Be prepared with examples of how rocks can change from
one type to another? Igneous to sedimentary? Igneous and
Sedimentary to Metamorphic? Metamorphic to Igneous or
Sedimentary?
4. Weathering
a. What is weathering? – Weathering is process that gradually
breaks down rocks and minerals.
b. What is erosion? – Erosion is the process of moving sediment
from one place to another by wind, water, and/or gravity.
c. What is the difference between physical (mechanical) and
chemical weathering? - Mechanical weathering only changes
the appearance of a material. Chemical weathering changes
the substance into something new.
2. Astronomy
a. What is Astronomy?
i. Aristotle
1. What were Aristotle’s beliefs about the universe? – Aristotle believed
that the universe was geocentric.
ii. Ptolemy
1. What were Ptolemy’s beliefs about the universe? – Ptolemy believed
that the universe was geocentric. He also believed that the planets,
sun and the moon moved in small circles, which he called orbits.
iii. What does geocentric mean? – Geocentric means that the Earth is in the
center of the universe and all the planets, moons, and stars revolve around
the Earth.
iv. What does heliocentric mean? – Heliocentric means that the sun is in the
center of our solar system and the planets and their moons revolve around
the sun.
v. What planets did the Ancient Greeks know of? – At this, ancient astronomers
knew only about Mercury, Venus, Earth, Mars, Jupiter, and Saturn.
vi. Copernicus
1. Who was Copernicus? Where was he from? What time period? Copernicus was a Polish astronomer in the 1500s.
2. What were Copernicus’ beliefs about the universe? – Copernicus
believed the solar system was heliocentric, not geocentric.
vii. Galileo
1. Who was Galileo? Where was he from? What time period? – Galileo
was an Italian astronomer in the early 1600s.
2. What were Galileo’s beliefs about the universe? – Galileo believed in
the heliocentric theory.
3. How did Galileo prove that our solar system is heliocentric? He proved
this theory by observing Jupiter’s moons and their revolutions
around Jupiter.
viii. Brahe and Kepler
1. What was their discovery? – Brahe and Kepler discovered that the
orbits of the planets were ellipses (oval shaped), not circular.
ix. Sir Isaac Newton
1. What were his discoveries?
a. What is gravity? – Gravity is a force that pulls an object
toward another object.
i. How does the mass of an object affect its gravity? – The
more mass an object has, the more gravitational force
it has.
b. What is inertia? – Inertia is the tendency of a moving object
to continue to move in a straight line, or the tendency of a
stationary object to stay in place.
c. How does the mass of an object affect its inertia? – The more
mass an object has, the more inertia it has.
b. What are the inner planets? – The inner planets are the 4 planets that are the closest
to the sun.
i. What is their order starting from the closest to the Sun? - Mercury, Venus,
Earth, Mars, Jupiter, Saturn, Uranus, Neptune, (Pluto…)
ii. What is a terrestrial planet? – Terrestrial planets are planets that have solid,
rocky surfaces.
iii. Mercury
1. Why does Mercury have such extreme differences in its temperature? Mercury has extreme differences in its temperature because it has a
very thin atmosphere. Since the atmosphere is what regulates
temperature on a planet, Mercury has a wide range in temperature
depending on which side of the planet is facing the Sun.
iv. Venus
1. Why is it called the morning/evening star? – Venus is called the
morning/evening star because it looks like a star in the sky.
2. Why is Venus not technically a star? – Venus is not a star because it
does not produce its own light. It is merely reflecting light from the
Sun.
3. Which is longer on Venus, 1 day or 1 year? – One day is longer on
Venus, because on rotation takes 8 months. One revolution (a year),
takes about 7.5 months.
4. Why is the Greenhouse affect happening on Venus? – The Greenhouse
Effect is occurring on Venus because the atmosphere of Venus is
mostly made of carbon dioxide.
5. What gas makes up most of Venus’ atmosphere? – Carbon dioxide.
v. Earth
1. What is a gas in the Earth’s atmosphere that is important for living
organisms? - Oxygen
2. What are the other major gases in the Earth’s atmosphere? – Nitrogen,
water vapor, and carbon dioxide.
3. How much of the Earth is water? – 70%
4. What are the 4 layers of the Earth? The four layers are the crust,
mantle, inner core, and outer core.
5. What are they made of? - The crust is made of rock, the mantle is
made of molten rock, the outer core is also made of molten rock, the
inner core is solid.
vi. Mars
1. Why is Mars known as the “Red Planet”? - Mars’ surface has a
brownish-red color because of the iron oxide (rust) that is on the
surface.
2. What is the major gas in Mars’ atmosphere? - Carbon dioxide
3. What 2 things does Mars have in common with Earth? – Two things
that Mars has in common with Earth is that there was once water
and that both planets have polar ice caps.
c. What are the outer planets?
i. What their order from closest to farthest? Jupiter, Saturn, Uranus, Neptune,
(Pluto)
ii. Which are terrestrial planets? Pluto
iii. Which are Gas Giants? Jupiter, Saturn, Uranus, and Neptune
1. What are the characteristics of the Gas Giants? – The Gas Giants are
much larger than the other planets of the solar system; they have
gaseous surfaces, and solid cores.
iv. Jupiter
1. What is Jupiter’s most prominent feature? – The Great Red Spot.
v. Saturn
1. What is Saturn’s most prominent feature? – Its rings.
2. What are the rings made of? – Saturn’s rings are made of ice and rock.
vi. Uranus - Uranus is the only planet that spins on a 90o
vii. What is Neptune’s most prominent feature? – Neptune’s blue atmosphere.
viii. Why is Pluto no longer classified as a planet? – Pluto is no longer a planet due
to its small size. The International Astronomical Union (IAU) reclassified
Pluto as a dwarf planet in 2006.