Download Amazing Rock Facts

Amazing Rock Facts!
1. The Earth formed from _______ and _____ pieces that accreted (clumped together under the pull of
gravity) that came from outer space about ____ million (4.6 billion) years ago!
Rocks are still falling to Earth everyday from space! About 1000 tons (2000 pounds) of rock falls every
year! Scientists even think some rocks that fell from space came from _______!
2. The Earth is composed of ___ primary layers: the _________ (very thin and where we live), the
_____________ (thick and oozy like a partially melted candy bar), and the ________ (partially molten and
primarily iron and nickel). Because the inner outer core is molten and moving it generates an electric
magnetic field that causes ____________ needles to point to the magnetic north pole. The positive and
negative poles of the Earth have flipped thousands of times throughout Earth history. In fact the north pole
moves anywhere from 6 to 25 miles every year! Scientists have recently noticed the poles starting to flip
again!
3. Almost all the rocks we pick up are from the crust. 98% of the Earth’s crust is made from only ___
elements. Rocks that are dark contain a high percentage of _________ and light colored rocks have a high
percentage of ___________ and ______________.
46.6% Oxygen (O)
27.7% Silica (Si)
8.1% Aluminum (Al)
5.0% Iron (Fe)
3.6% Calcium (Ca)
2.8% Sodium (Na)
2.6% Potassium (K)
2.1% Magnesium (Mg)
So almost any rock we pick up is made of minerals of only these eight elements (minerals are combinations
of elements!
4. There are 3 general categories of rocks based on how they are made: ____________ rocks (from melted
rock, magma or lava), ________________ rock (from pieces of rock or dissolved minerals that settle in
water often making layered rocks), and ____________________ rocks (rocks that change under great heat
and pressure while buried in the Earth over millions of years). 75% of rocks that cover the surface of the
Earth are igneous rocks and most of them are in the ocean. The ocean covers 70% of the Earth’s surface!
Maybe a better name for Earth would be ____________!
5. Rocks seem like they have been around forever and will last for eternity, but they are constantly
__________ in a process called the rock ____________. Our scientific theory that explains what drive the
rock cycle is _______________ Tectonics. Igneous rocks build volcanoes that can be worn away (eroded)
by rain, snow, and ice, and sediments (pieces of the volcano) are washed down rivers to oceans where they
settle in layers to become sedimentary rocks. Sedimentary rocks are moved along earthquake faults where
they are compressed and heated and changed into metamorphic rocks. The oldest known rocks, about
_______ million (4 billion) years old, are found in northern Canada. One day about 5 billion years from
now all Earth rocks will become molten as the Earth is consumed by a swelling Sun that will engulf and
bake the Earth! Then all the rocks on Earth will become ________________ type rocks again!
6. Peridotite is an extremely rare rock at Earth’s surface that makes up most of the mantle. California has a
higher percentage of this rock than most other places around the world. In fact our state rock is
____________ (a green smooth rock). It is altered peridotite that mixed with water as it was moved from
the ocean floor onto land along earthquake faults and changed the minerals and the rock making it green
and smooth. Serpentine often has faint lines called ____________________ that are little chatter marks
where the rock scraped against other rocks as it moved along earthquake ______________.
7. The state mineral is ___________. Gold is found as a pure ______________ although it is often mixed
in jewelry with other metals to make an ______________. Gold forms along with volcanic rocks but is
often mined from ancient _______________. What process transports gold into rivers? _______________
Answer the amazing rock facts questions below:
1. What two materials from outer space formed the early Earth?
2. How long ago did the Earth form?
3. How many tons of rocks fall from space every year?
4. How much is a ton?
5. Name the 3 primary layers of the Earth.
6. Why does the earth have an electric magnetic field?
7. How much does the north magnetic pole move every year?
8. How many elements make up the Earth’s crust?
9. Write the symbols of the elements that primarily make up the Earth’s crust.
10. What are the 3 general categories of rocks?
11. Where are most of the Earth’s igneous rocks found?
12. What Earth process constantly recycles rocks?
13. How old are the oldest known rocks and where are they found?
14. What will all rocks become in about 5 billion years?
15. What rock makes up most of the mantle?
16. What is the California state rock?
17. Serpentine is an altered form of what rock?
18. What causes slickensides on serpentine?
19. What is the California state mineral?
20. Where is gold often found?
21. What process moves gold into ancient riverbeds?