Geology/Rocks Study Guide
Tentative Test Date: November 20, 2015
The rock cycle has an impact on the physical characteristics of the Earth.
What is a rock?
Rock
 A material made up of one or more minerals
What is a mineral?
Mineral
 A true mineral has 3 features:
 A solid material with particles arranged in a
repeating pattern
 Usually made from material that was never alive
(inorganic)
 Formed in nature (not man-made)
 Examples:
 Quartz
 Talc
 Hematite
 Sapphires & rubies
 Emeralds
 Diamonds
Types of Data & Observations
Quantitative
Qualitative
 Data recorded using numbers and measurements
 Length, height, time, temperature, cost, age, etc.
 Descriptions of properties that can be observed but not
measured
 Color, texture, smell, taste, etc.
Properties of Minerals
Property
Hardness
Luster
Streak
Scientists use properties of minerals to classify them.
 A characteristic of a substance, object, or organism
 We describe something or someone by its properties.
Examples of properties below:
 A mineral’s ability to scratch another mineral,
measured by the Mohs’ hardness scale
 How minerals reflect light, can be metallic, earthly,
glassy, etc.
 The color left behind when a rock is rubbed across a
streak plate
 The streak can be a different color than the observed
color of the mineral
Properties of Rocks
Composition
Grain size
Color
 What mineral(s) a rock is made of
 How big the crystals of an igneous rock appear to be
 A property of rocks/minerals that you can easily see
Types of Rock
How do a rock’s properties determine how it is used in every day life?
Classification
Igneous
Metamorphic
Sedimentary
 The grouping of things by a set of rules
 A type of rock that forms when melted rock (magma or
lava) hardens
 Examples:
 Granite
 Basalt
 A type of rock that forms when other rocks and/or
minerals are changed by heat or pressure. Although heat
is involved, the rocks don’t completely melt.
 Examples:
 Gneiss
 Marble
 Slate
 A type of rock formed by layers of sediments that were
squeezed and stuck together over a long time.
 Sedimentary rock layers form on top of each other. The
oldest layers are found at the bottom.
 Examples:
 Limestone
 Shale
 Sandstone
 Coal
The Rock Cycle
How does the rock cycle compare to other natural cycles? (like the water cycle)
Rock Cycle
Weathering
Sediment
Strata
Volcano
Magma
Lava
 The slow, never-ending process of rock changes
 Rocks are being constantly changed chemically and
physically
 The process of breaking rock into sediment (sand, soil &
other tiny pieces)
 Small pieces of rock, sand and soil that have been broken
off of larger pieces of rock by weathering
 Sediment can settle in layers to become sedimentary
rock
 Sediment can also be moved from one place to another
by wind and water
 Layers
 The different layers in sedimentary rock are sometimes
called strata
 A mountain formed by lava and ash
 Melted rock from Earth’s mantle
 Magma when it is above Earth’s surface
Diagram of the Rock Cycle
Figure 1: The Rock Cycle, from http://www.cotf.edu/ete/modules/msese/earthsysflr/rock.html
Rocks & the Past
How do the physical characteristics of rocks help us understand the past?
Erosion
Fossil
Trace Fossils
Mold or Cast
Fossils
Index Fossils
Fossil Fuels
 The process of moving sediment from one place to
another
 The remains or traces of past life found in sedimentary
rock
 Fossils that are not body parts, but show something an
organism left behind (footprints, etc.)
 Fossils in the shape of an organism (dinosaur bones,
shark teeth, fern imprints, etc.)
 Help identify how old a rock layer or other fossils are
 An energy rich resource formed from the buried
remains of once-living organisms.
 Coal, Oil, Natural Gas, etc.
Navigation
Navigation
Compass
 How to get from one place to another
 Device that uses Earth’s magnetic field to help in
finding north for navigation
Useful information from previous units
Earth’s Structure
Crust
Mantle
Outer Core
Inner Core
Question
Research
Hypothesis
Observe
Data
Record
Analyze &
Conclusion
 The thin, outer layer of Earth
 The layer of rock beneath Earth’s crust
 The inner part of the mantle is very hot,
which makes it soft
 The layer of melted iron beneath the
mantle
 Source of Earth’s magnetic field
 The center layer of Earth, very hot
 The inner core is under very heavy
pressure, so it stays solid, even though
it is hot enough to be melted.
Scientific Process
 Start with a question to answer or a problem to solve
 Find out what other people already have discovered about the
topic
 An educated guess to answer your question. It should be stated in
a way you can measure or observe
 To notice the properties of something. Observations can be made
with your 5 senses.
 Observations can also be measured to get more exact information
 The information gathered from observing
 Collect your information in a clear way
 Once your experiment is complete, look at the recorded data and
decide whether or not it supports your hypothesis