Rocks and Minerals Flashcards
Describe the Earth’s shape
It’s a sphere
Describe the Earth’s size
Circumference: 40,074 km
Diameter: 12,756 km
What are three examples that explain how the Earth is round?
- Mast of a ship on the horizon
- Nighttime sky
- Lunar eclipse
What is density?
Mass divided by volume
What is the average density of the earth?
5.5 g/cc
What is the average density of the crust?
2.8 g/cc
What is the temp. of the earth just below the surface?
The average temp. of the year
What makes the crust of the earth hot?
Some heat is left over from the formation of the earth, other heat comes from the decay of radioactive elements
What is a rock forming mineral, it’s minerals are abundant?
Silicates
What are the physical properties of a mineral?
Color, Luster, and Crystal Shape
What is the study of minerals and their properties?
Mineralogy
What is the test where they test the color of the powder of the minerals?
Streak Test
What is the test where they test to see if it shines like polished metal or if it is dull?
Metallic and Nonmetallic Test
What is the test where they test the tendency of a mineral to break along flat surfaces?
Cleavage Test
What is the test where they test the resistance to being scratched?
Hardness test
What are the four tests that they do to identify minerals?
- Streak
- Metallic and Nonmetallic
- Cleavage
- Hardness
What is a scale from 1-10, with 1 being the softest and 10 being the hardest?
Moh’s Scale
Prior to 1790’s how did people think the surface of the earth formed?
By a spectacular catastrophe
What did James Hutton say about the formation of the earth’s surface?
- The present was the key to the past
- The geologic processes now were happening in the past
- The features of the earth were created by the same processes over a long period of time
What is a group of minerals bonded together in some way?
A rock
What are the three types of rocks?
- Igneous
- Sedimentary
- Metamorphic
What is the name of the rock that was formed by the cooling of magma?
Igneous Rock
What is the name of the rock that was formed by the hardening and cementing of layers of sediments?
Sedimentary Rock
What is the name of the rock that was formed when existing rocks are changed by heat and pressure?
Metamorphic Rock
What is the difference between intrusive and extrusive igneous rock?
Intrusive is formed when magma cools underground and extrusive is formed when magma cools above the earth
What determines the texture of igneous rocks?
The size, shape, and arrangements of its mineral crystals
What is fast moving magma?
Mafic
What is slow moving magma?
Felsic
List the types of sedimentary rocks
- Clastic
- Chemical
- Organic
Which rock is formed by other fragments of rock?
Clastic Rock
Which rock is formed by mineral grains that fall out of solution?
Chemical Rock
Which rock is formed by remains of plants and animals?
Organic Rock
How do clastic rocks form?
Weathering breaks the rocks apart and natural cement holds the broken off pieces together
What is the arrangements of rocks in visible layers?
Stratification
Where are the oldest rocks found?
At the bottom
What occurs when large areas of rock are under intense pressure and heat that changes their form?
Regional Metamorphic
What occurs when hot magma forces its way over existing rock?
Contact Metamorphic
What is a thin layer of rock a few tens of miles thick?
Crust
What is 1800 miles of putty like molten rock?
Mantle
What is the core’s size?
The size of the moon
What is made up of a liquid metal?
The Outer Core Layer
What is made up of a solid metal?
The Inner Core Layer
What is the source of the heat of the earth’s core?
- Impact of other planets
2. Radioactive Elements
What are the volcanic areas that are thought to come from hot sections of the mantle?
Hotspots
How does the magnetic field flow around the earth?
It flows out of the south pole, around the earth, and flows back in through the north pole
How would the flip of the magnetic field flow around the earth?
- The earth would have multiple poles at random locations
2. We could experience heavy doses of solar radiation that can cause a cancer epidemic
Does Mars have a magnetic field? How do scientists know if it did or did not?
No, the minerals of Mars’ crust showed that it had one once
Why didn’t the earth’s core cool like Mars?
Mars is smaller and cools faster
What would happen to the earth if we lose the magnetic field that surrounds the earth?
Solar radiation would blow away our atmosphere. Our water would disappear due to having no atmosphere.
