Welcome to PSC 1210
Earth and Space Science for
The mostly (but not entirely!) on-line version
Goals of PSC 1210
Understand important concepts in Earth and Space Science
Develop science process skills
Appreciate and apply the scientific method
Learn using techniques you will apply as a teacher (harder with on-line version)
On line version will differ from previous versions- less hands on, more individual research/problem solving
Goals of Today’s Lecture
Terminology, vocabulary, intro to writing techniques
Quick review of math concepts used in our class
Mapping- beginning the use of Google Earth (or google maps)
Some Science Terminology, 1
scientific fact – specific, verifiable information
*Sulfur is a yellow mineral.
*Granite is an igneous rock.
hypothesis – possible action and/or explanation for a behavior or an observation; must be tested through experimentation
*The continents can move around
Science starts with hypotheses and sets up tests for failure.
Some Science Terminology, 2
law - generalized statement of a relationship between variables in a system based on repeated experimentation; can be used to predict behavior of a system. Laws are always true.
*Less dense fluids float above more dense fluids.
theory - generalized explanation for observations based on repeated experimentation or observations
*Plate tectonics is the theory which explains that continents move because of convection currents in the mantle.
Laws describe things, but theories also explain them
How to recognize?
Hypothesis: If …… then……. or “I think that”
Fact: This is true
Law: This is always true. Formulas.
Theory: This is always true because.
This explains why this happens.
Make an observation that raises a question State a question
Determine a possible reason for the observation Pose a hypothesis
Design and carry out an investigation to support or disprove the hypothesis Do an experiment
Or make an observation or do a simulation on a computer
Evaluate hypothesis- is your hypothesis strengthened or disproven?
What additional work needs to be done to test the hypothesis? Or…. Turn it into a law or theory?
Independent variable = one changed by the experimenter
Dependent variable = one that changes as a result of a change in the independent variable
Controlled variable = any property that is not being investigated and must remain the same during the experiment
Make an observation that raises a question. Birds always eat at my red feeder and
ignore my blue one. Why?
Determine a possible reason for the observation. Pose a hypothesis.
Birds prefer red feeders.
Design and carry out an investigation to prove or disprove the hypothesis
Determine the variables:
Independent = color of the feeder
Dependent = # of birds at the feeder
Determine the variables:
Controlled = type of feeder, type of food, time of day recorded, height of feeder, location of feeder…
Set up 3 blue and three red identical bird feeders. At a set time each day for 10 days, record how many birds are at each feeder. Record data in a suitable table.
Compile information from the experiment.
Analyze the data. Make a bar graph of the number of birds at each color feeder for each day.
Decide if the hypothesis was correct. Make a conclusion
I was wrong. The number of birds were almost the same. Perhaps it was because I put different food in the red feeder than the blue feeder. I had not controlled for food type!
But this is still legitimate science testing a hypothesis
For weather observation
Hypothesis: If its 50 degrees when I wake up, then it will be 70 degrees in the
How does the afternoon temperature depend upon the morning
Collect data: Turns out that need to control for different conditions
Is it sunny or cloudy? Raining?
Is it windy? Which way is the wind blowing?
Classify for the different conditions:
Under what circumstances does the data support the hypothesis?
Theory: If its sunny, the afternoon temperature will be warmer than if
its cloudy because the sun’s rays can more readily warm the surface.
What is a Misconception?
Incorrect understanding of term or process: “Theoretical misunderstanding”
Not merely a misfact
Can be taught to you or you can come to it based on your personal experience
Highly resistant to change
Some Misconceptions in Earth/Space Science
The seasons are caused by the Earth’s distance from the Sun.
Continents do not move.
Most rivers flow “down” from north to south.
Some Misconceptions in Earth/Space Science
The soil we see today has always existed.
Dinosaurs and humans existed at the same time.
The phases of the Moon are caused by a shadow from the Earth.
General theme to misconceptions: earth/space does not change
In this class we’ll learn about how the earth changes and evolves
Earth’s crust and interior cycles
Water (hydrology) cycle
Atmospheric and climate cycles
Outer Space also changes
other planets have cycles, not always the same as the earth!
solar systems and stars are formed, destroyed and reform
Math in PSC 1210
1. Fractions better known as ratios in science
Consider fraction 1/2. Compares the number 1 (numerator)
to the number 2 (denominator)
In science, the numerator and denominator often describe different
Example: Driving- mph. Miles per hour
Speed or velocity: A ratio of distance divided by time
60 mph = 60 miles/1 hour = 120 miles/2 hours = 30 miles/0.5 hours
Verbally, the word “per” is key in describing a ratio
What kind of ratios will we use?
(notice the word “per” in all three examples)
Density. Amount of mass per volume.
typically the mass is in grams (or maybe kilograms)
and the volume is in cubic centimeters (a cube a centimeter
long on all sides. A centimeter is about the size of your
Density tells you how packed together the molecules and
2. Velocity- as discussed on the other page
3. Gradients- rate of change. Like a mountain slope- is it steep or flat?
feet per mile
A steep slope is walking one mile and going up (or down) a
thousand feet: 1000 ft/mile (same as 2000 ft/2 miles etc.)
Flat is walking one mile and only going up (or down) 20 feet or
Another gradient- change in temperature
You drive 100 miles and its 30 degrees warmer (this can
happen and we’ll discuss how)
30 degrees/100 miles = 0.3 degrees/mile
Calculations with ratios- basic algebra
You are given two things, find the third
Example: you have 4 hours and you drive 65 miles
per hour. How far do you go?
velocity x time = distance
65 miles/hour x 4 hours = 260 miles
Complication with using ratios- need to pay attention to units
Consider: you drive 60 mph- how many miles do you drive in 60 seconds?
60 miles 1 hour
------ x ------- x 60 seconds Need conversion!
hour 3600 seconds
Units appear on top and bottom cancel out. We’re left with
60 x 60
-------- = 1 mile so….. 60 mph is 1 mile per 60 seconds or 1 mile per minute
60 miles 1 hour
----- x ------- x 60 seconds
hour 3600 seconds
(only thing left is “miles”)
Another example of conversions using density
How much does a gallon of water weigh??
We know density of water is 1 gram/cc (cc means cubic centimeter)
Need conversion factor: how many cc’s in a gallon?
(from google: 3785 cc’s per gallon)
1 gram 3785 cc’s
----- x ----- = 3785 grams
Last conversion: 454 grams/pound
3785 grams x 1 pound
------ = 8.3 pounds
The key to these conversions is to put the unit you want to eliminate on both top and bottom
Math in PSC 1210- PART 2
Be comfortable with big numbers! Exponents
The Earth is 4.5 billions of years old.
The solar system (sun + planets) is 6 billion miles across.
Billions, millions, thousands, hundreds………….. etc
1,000,000,000 = 109 = 1 billion, i.e. 1 followed by 9 zeros
1,000,000 = 106 = 1 million
1,000 = 103 = 1 thousand
1 million x 1 thousand (6 zeros + 3 zeros = 9 zeros) = 1 billion
1 thousand x 1 thousand (3 zeros + 3 zeros = 6 zeros) = 1 million
In between we have 10,000 or 100,000 (4 zeros, 5 zeros) etc.
What we’re interested in about these numbers
Not so much exact values (very hard to know), but how many zeros-
what is the exponent?
Age of earth: measured in billions years (OK, this we know is 4.5 billion)
Movement of continents: measured in tens and hundreds of millions (7 or 8 zeros)
Ice ages: measured in thousands of years (3 to 4 zeros)
Changes in stream flow, erosion etc: could be tens, hundreds or thousands
of years (1,2 or 3 zeros)
Damage from Earthquakes: less than 1 year (more likely a tiny fraction of a year)
Size of earth and smaller planets: thousands of miles across (3 zeros)
Size of Jupiter and bigger planets: tens of thousands of miles across (4 zeros)
Size of sun and stars: hundreds of thousands of miles or even millions of miles
across (5 or 6 zeros)
Goal for end of class
Be able to make some simple estimates of time, space and speed of
events in earth and space science.
Over a wide ranges of spatial and temporal scales
(from seconds to billions of years and from centimeters to billions of
Google Maps vs. Google Earth
Similar but not the same
Google Maps (good for driving directions)
Street views, traffic, driving directions
2. Google Earth – like “Maps” but for earth as a planet
Go to https://www.google.com/earth/ and then launch it. (or perhaps download or get from app store depending upon device
Google Maps is for navigating around, Google Earth is for exploring our planet as a whole and is better for now, but
I think google maps can work. Google Earth works better on a computer/laptop than a ipad/phone.
Google Earth shows
details of surface (and not only that!)
but not clouds
Satellite photo shows
lots of clouds
but not details of surfaces
Using Google Earth vs. Satellite image
what are the differences?
Using Google Earth and Google Maps
4 skills to practice today
1. Learn to zoom in and out. The picture of the earth as a planet is very
zoomed “out”. You can zoom in all the way to see buildings.
2. Learn to see the place names in Google Earth
3. Learn to mark distances between two points in Google Earth. Try different
4. Some simple analysis of geography
When we zoom out……….. What do we see?
(either +/- on computer, or with spreading fingers on
Blue (Earth is a “blue marble”)- surface is mostly water
Green – biology (not really subject of this class, but we’ll mention
it on occasion)
brown- surface without biology, deserts
(we will discuss why they occur and why they are located
where they are)
Interesting to compare to Mars and Moon (not sure
how to get this on my ipad, it’s a tab on top on the computer)
What colors do they show? How do they
agree or disagree with Earth’s colors
Google Moon and Google Mars for comparison
Which object is more similar to earth? And why?
Zoom in- look for places
Expand the layers tab on left. Check borders and labels,
Countries- yellow labels on computer, white on Ipad
Places/natural features- green
(compare Blue Ridge Mountains with Appalachian Mountains-
Whats the difference? Unfortunately, not shown in Ipad)
go to triple line tab on left, and touch “map style” (the symbol
is called the “layers” symbol),
play with checking “clean” or “exploration” or everything
In general, the Ipad is more finicky when names show up- I have to
play with zooming in or out
Look at countries, cities, continents
How many continents and oceans?
What is the meaning of a continent or ocean. Not a good answer!
large, continuous, discrete mass of land,
ideally separated by an expanse of water.
But when is it a continent and when is it an island? Somewhat arbitrary.
Comparing Greenland (island) vs. Australia (continent).
A combination of reasons, some of which we’ll discuss.
- Greenland animals and plants are similar to N. America; Australia is
- Australia is its own tectonic plate (whats that? Stay tuned!)
- Culturally, very different than the rest of Asia
None of these are great reasons, but they add up
Europe is considered a separate continent from Asia. Does that make sense?
Look at Google Earth and you decide!
Oceans- how many oceans do we have?
4 (Atlantic, Pacific, Indian, Arctic)
Look at google earth
Finally, where are there mountains? What do you see where its blue?
Google Earth shows the terrain under the water – hugely important for
Combination of minerals rocks
Rock Types - Igneous
Igneous means “formed from fire”
Rocks formed by cooling and crystallization of molten material called magma (or lava)
(remember the two types of magma: basaltic and granitic and their differences)
Granite and basalt look quite different because of a key difference in how they are formed
Granite vs. Basalt
Granitic magma is less dense- silica rich.
Granitic magma crystallizes last (remains liquid longer)
Magma that comes out of the ground quickly and becomes lava
is basaltic. Hasn’t had time for the heavy stuff to settle out. Lava cools
very quickly- days/weeks.
Magma that remains underground where the silica rich liquid will separate
out will also cool much more slowly and can take millions of years to finally
get cold enough to crystallize
Analogy: shake up olive oil and water and stick it immediately in the freezer (basalt)
vs. let it for a long time and cool gradually degree by degree so that it freezes
very very slowly (the olive oil is like the granitic magma which will float to the top)
Granite and Basalt look very different
Granite: has time to grow large visible crystals in various random patterns
Granite is often sparkly
Basalt- black volcanic rock.
Crystals are microscopic. Really fast cooling gives you glass (no crystals)
Basalt on the beaches of Oregon
Look at rock samples on webcam…..
(“dragon-glass in Game of Thrones”!)
Crystal: a solid with an organized structure. Atoms have exact
and repetitive spacing, angles etc.
These can be different
atoms depending upon chemical
formula. But it will be in a regularly
In glass, it cooled so quickly the
the atoms aren’t lined up in any
Table salt has a
crystal pattern of
and chlorine atoms
Can be different atoms, depending
Upon chemical formula, but the
Pattern will be repetitive
Rock Types - Sedimentary
Rock formed from accumulation of weathered* materials (sediments)
may contain fossils;
may show layering;
may have a conglomerate nature with rounded particles or cementation evident;
may contain only one mineral as a result of chemical deposition
Generally dull in appearance (no sparkles!)
* So what’s “weathered” mean??? (future lesson: means “broken up”)
Types of sedimentary rocks- depends upon size of sediments
Mud – smallest particles
Sand- medium sized
Gravel- can look like pebbles glued together
All involved with water sedimentary rock requires
liquid water to form
What does that imply for the Grand Canyon?
See webcam for samples…
Rock Types - Metamorphic
Term means “changed from”
Rock formed from pre-existing rocks through the action of high heat (no melting) and pressure
May be very hard and may show crystals but they will be in a linear pattern (foliation) or may show elongation or folding that results from high pressure; certain minerals only form in metamorphic rocks.
Process for making metamorphic rock is like putting clay in a kiln and making pottery
Two types of Metamorphic - 1
flat crystals formed in when sedimentary
rocks are heated and compressed
(a folio is a flat sheet of paper)
Look at webcam
Crystals and foliation:
Crystals will grow perpendicular to the pressure
Flat sheets like with mica (found in
Two types of Metamorphic - 2
Non-foliated (no flat, elongated crystals)
(harder to ID, won’t have to recognize)
Checklist for Identifying Rocks
|Rock type||Visible crystals (sparkles)?||Banded or layered?||Fossils?||Pebbles glued together?|
|Igneous||Yes for granite||No, crystals are random||No, never||No|
|Sedimentary||No- dull in color||Often Flat||Yes||Yes for conglomerates|
|Metamorphic||Yes for foliated||Yes, for foliated but irregular||No, never||No|
Why can’t igneous rock or metamorphic rock have fossils?
Rocks can be changed from one type to another through natural geological processes.
The series of processes that comprise these transformations is called the rock cycle.
See Figure 20.37 of text
Studying the details of the rock cycle
We next will look at the left side of the cycle. How, where and why rocks are heated,
melted and crystallized. Right hand side (sedimentary rock formation) is
part of water cycle- this will be our 2nd unit starting in a couple of weeks
Given a random pile of stones-
how would you sort them?
What classification system would you adopt?
Given a random pile of stones-
how would you sort them?
What classification system would you adopt?
My favorite: purity
All one composition
Rocks and Minerals I
What distinguishes rocks from minerals?
A mineral is a homogeneous solid and has a fixed composition. It is formed through natural processes and is usually inorganic. It has a defined crystal structure (glass is not a mineral. Its pure, but does not have a crystal structure- more on this next time).
John H. Betts
What distinguishes rocks from minerals?
A rock is heterogeneous and formed from two or more minerals.
So my favorite characteristic for
sorting the piles, is purity. (recognizing that
it doesn’t cover glass). But it is generally
good for distinguishing rocks vs.
Might have noticed that the pure specimens
tended to be smaller
Let’s take a look at some of the characteristics of minerals and their tests.
A mineral has a definite chemical formula such as: NaCl, called halite; CuAl6(PO4)4(OH)8·4(H2O), known as turquoise; or (K(Mg,Fe)3AlSi3O10)(OH)2) which is biotite.
Don’t worry about the details of these complicated formulas!
Color alone is not the best identifier of
a mineral. This is related to part of the
homework “fools gold” looks “gold”.
The powdered color of a mineral is characteristic. You can see the color by dragging the mineral across a rough surface. The result is called a streak.
Mineral luster is a term for describing the way light is reflected from the surface of a mineral.
Galena - metallic
Spodumene – glassy
Hardness is a mineral’s resistance to being scratched. A harder mineral will scratch a softer one. Hardness is a relative measure and is assigned a number based on the Mohs Scale.
|Hardness (Mohs)||Mineral||Some familiar objects|
|2||Gypsum (CaSO4·2H2O)||Fingernail: 2.5 Gold or silver 2.5-3|
|3||Calcite (CaCO3)||Copper penny: 3|
|5||Apatite (Ca5(PO4)3(OH-,Cl-,F-))||Regular knife blade 5-6|
|6||Orthoclase Feldspar (KAlSi3O8)||Glass: 5-7|
|7||Quartz (SiO2)||Hardened steel file: 7”|
Try and scratch
Other Mineral Properties: Chemistry
Some carbonate (they must have CO3 as part of their formula) minerals react to an acid such as HCl. The reaction produces carbon dioxide gas which will “fizz” on the mineral surface.
Some minerals show magnetism or are attracted to magnets. Magnetite is the best example and has been used to make magnets. Has iron (Fe) and oxygen (O)
All minerals have a density
Density: amount of matter in a given volume of the substance.
M: mass (related to weight). Typically expressed in grams (gm) or kilograms (kg). A kg is a bit over 2 pounds. A gm is less than 1 ounce.
V: volume. Typically expressed in cubic centimeters (written either as cc or as cm3) or cubic meters (m3) .
Densities that are high or low may be helpful in identifying the mineral.
How can we measure density? Two steps
How can we measure density?
Step 1: find the mass weigh your sample on a scale
Answer will be in grams
(If desired, can convert 454 grams per pound, but
densities are typically given as gm/cc)
Step 2: find out how big it is (the volume)
use water displacement method (next slide)
(also Section 5.3 of text covers this but in more detail
than we need)
Measuring volume- the water displacement method
Fill beaker partway with water- measure the water level
the answer is in milliliters (ml) which conveniently happen
to equal cubic centimeters (cc)
1 ml = 1 cc
2. Plop your sample in- what happens to the water level?
3. Measure the water level again
Displacement = final volume – initial volume = volume of sample
Put it all together
mass of sample
Density = ----------------------
final volume – initial volume
Instructor Demo: measure density of quartz, olivine, hematite
(why these three minerals?........ Stay tuned)
|Specimen||Mass (gm)||Initial water volume (ml)||Final water level (ml)||Displacement volume (ml) (final-initial)||Density measured (actual) gm/cc|
If you know two of three (mass, volume (i.e displacement), density), you
can always find the third.
Why those three minerals?
Quartz: composed of Silicon and oxygen SiO2
Si and O are the most common elements in earth’s crust
Combination called “silica”. Quartz is pure silica. So is
(often) beach sand
Other common minerals are silica + some metal called silicates.
Olivine: A silicate often bound up with iron. Iron is very dense
which is why olivine is more dense than pure silica
Hematite: not a silicate. Combination of iron and oxygen. Extra
presence of ion makes this the densest of the three.
These three elements: Iron (symbol Fe), Silicon, and oxygen are the
Most important elements to know for the solid earth.
1. Oxygen: most common element earth’s crust
2. Silicon: #2 most common in earth’s crust (always bound w/ oxygen)
3. Iron: tied with oxygen for most common element in whole earth, but most of it is deep down towards the earth’s center. Less (but some) in crust
1. Oxygen: Part of air, water and solid earth, most common in rocks we see
2. Silicon: #2 important for rocks we see, combines with oxygen to make silica
3. Iron: Most important for deep within the earth. Densest of these 7.
4. Carbon: combines with oxygen
carbonates in rock (acid test), carbon dioxide in air (plants use)
5. Hydrogen: part of water, simplest element, most common element in universe
6. Helium: #2 most common in universe, #2 simplest
7. Nitrogen: most common constituent of the air (not oxygen!)
For rocks and minerals we’re only interested in 1-3, altho 4 is present
Elements you will encounter in this course (and need to know)
The Magnificent Seven!
Getting ready to mix minerals together.
Lets just summarize mineral properties
Color: not as reliable due to effects of small impurities
Streak: color of powered form
Hardness: resistance to scratching
Density: reflects chemical composition important
Reactivity to acid- useful for chemical compositon
Magnetism? can tell you if you have iron (high density)
Consider combinations of minerals (i.e. rocks)
To combine, we melt. We then get …………?
Where does the heat come from to melt?
Magma (molten material underground)
Lava (molten material on the surface)
Only two sources of heat for the earth
1. the sun (not hot enough to melt rock/minerals)
2. the earth’s deep interior
So melting of the solid earth occurs underground where the temperature
is hotter. This produces magma.
Note: a misconception- the earth underground is not always molten
It depends upon other factors like the pressure
Magma will have different densities depending upon the mixture of
What happens when you mix liquids of different densities? (or a solid
and liquid when they are different densities).
See demo with olive oil, ice cube, plain water
Melting different combinations of minerals
Density of Olive oil = 0.92 gm/cc
Density of Ice = 0.93 gm/cc
Density of Water = 1.0 gm/cc
Fun website (if you have adobe flash)
Buoyancy: less dense floats above more dense
What happens when a liquid is cooled and solidifies?
More rigorous term crystallization
What happens when magma crystallizes?
you get igneous rock, the first of the 3 main types of rock
Different types of magma different types of igneous rock with different
Two types of igneous rock
Silica rich magma (i.e. ½ pure quartz, no iron, some other lighter metals):
Density about 2.6-2.7 gm/cc
Silica poor magma (i.e. has silicates, but no pure quartz, more metals
including iron from melted olivine):
Density about 2.9-3 gm/cc
Since silica has a lower density than iron, granite is lower
density than basalt.
Silica also melts more easily and crystallizes more slowly
Section 20.7 of text: two categories of igneous rock
basalt crystallized lava (surface or ocean floor)
granite crystallized magma below surface
Silica rich vs. silica poor (fig 20.13 in text)
This is how magma can generate different
Igneous rocks- the silica-poor stuff crystallizes first, sinks and lets
the silica-rich magma flow upwards
Granite “floats” on top of basalt
Granitic magma stays liquid longer. Is less dense
“floats” higher than basalt
(see Section 5.4 of text on buoyancy picture of floating
Basalt Oceanic Crust (bottom of the sea floor)
Granite Continental Crust which sits on top of basalt
In our ordinary daily life, what kind of igneous rocks will we usually see?
Basalt is most common igneous rock, but harder to see on earth’s surface. So whats the best way to see it?
Minerals and their properties
How density can vary, can be measured and can be used
to understand mixtures of minerals.
Lays foundation for understand structure of earth’s
outer shell, the crust.