GEOSC 10 FINAL

Pictures 1 and 2 show two very different looking rivers. What can you say about them?

1 is a meandering stream with clay-rich banks, and 2 is a braided stream with sandy or gravelly banks.

You start with 400 parent atoms of a particular radioactive type, which decays in a single step to give a stable offspring, and you start with none of those stable offspring. You wait just long enough for two half lives to pass. You should expect to have how many offspring atoms (on average)(remember that the number of parents and the number of offspring add up to 400, so if you have 10 parents, you have 390 offspring because 10 and 390 add up to 400, and if you have 20 parents you have 380 offspring, and so on):

300 You start with 400 parent atoms of a particular radioactive type, which decays in a single step to give a stable offspring, and you start with none of those stable offspring. You wait just long enough for two half lives to pass. You should expect to have how many offspring atoms (on average)(remember that the number of parents and the number of offspring add up to 400, so if you have 10 parents, you have 390 offspring because 10 and 390 add up to 400, and if you have 20 parents you have 380 offspring, and so on):

The great diversification of shelly fossils that marks the beginning of the Paleozoic Era occurred about:

570,000,000 years ago. NOTE: Humans were trotting around 57,000 years ago. 570,000 years is barely enough time for evolution to have changed large animals a bit, and although 5,700,000 years is enough time for noticeable change of large animals—increase in maximum size of members of the horse family, for example—the huge changes since the dinosaurs needed a bit more than 57,000,000 years (dinosaur extinction was about 65,000,000 years ago). The Paleozoic came before that, and 570,000,000 years is about right. 5,700,000,000 years is more than the age of the Earth, and so doesn't work very well.

In the first picture, Dr. Alley is pointing to a brownish zone exposed in the low bluff along Coast Guard Beach, Cape Cod National Seashore. The brown zone is rounded on the bottom, flat on the top, rests on sand and gravel, and has sand dunes on top. In the lower picture, Dr. Alley is showing that the brown zone contains twigs and other organic material.What is the brown zone doing here?

A block of ice from the glacier fell into an outwash plain deposited by the glacier's meltwater streams, and the ice later melted to leave a lake, the lake filled with peat and other organic materials, and was later buried by sand dunes, with erosion of coastal bluffs now exposing the deposit. NOTE: Cape Cod is a creature of the glaciers, and most of the Cape's lakes started by melting of buried ice blocks. Twigs are not brown algae. Arms of the sea are usually a bit bigger than this, although there was a big lake trapped in what is now Cape Cod Bay by the ice. And we have to wonder, is there a rock band named "Whale poop"?

The bowl-shaped feature in the foreground of the above photo is:

A cirque, a bowl gnawed into a mountain at the head of a glacier. NOTE: This is indeed a cirque. The strong layering of the rock material is suggestive of bedrock, not loose pieces as seen in moraines and blockfields. This is basaltic bedrock from the breakup that formed the Atlantic, but basaltic bedrock does not dissolve easily in acidic groundwater. And whoooo, what would the alien use for TP???

Near Aaronsburg, PA, a company wanted to start a limestone quarry, and planned to pump lots of water out of the ground to make things fairly dry near the quarry so it wouldn't fill with water. Concern was raised—would this affect the nearby trout streams? So, a little harmless dye was placed in a sinkhole next to the proposed quarry, and a fire-engine pumper added a lot of water to the sinkhole. How long did it take, or will take, for the dye to reach the trout stream?

A few hours to days. NOTE: The dye showed up in a few hours, and the quarry was not excavated. Sinkholes often connect directly and quickly to underground caves or big cracks, and thus to streams, allowing rapid drainage. There are rock units that would hold their water for centuries or millennia, but such units have small spaces, not caves and sinkholes. Local sinkholes do drain to trout streams, and Michigan has to make their own water pollution because water pollution from Pennsylvania does not reach them. (Fun thing to do if you're bored: fit this question into the Michigan fight song.)

This rock in the picture above was modified by:

A glacier, which scratched and polished the rock at A and plucked blocks loose at B, as the ice moved from A to B. NOTE: Indeed, ice sandpapers and striates the rocks it hits first, and then plucks blocks loose from the other side. And the striae go in the direction that the ice moved.

Two yellow lines have been drawn on the picture by the instructional team. These lines follow an interesting surface, which separate flat-lying sedimentary rocks, on top, from slanting sedimentary rocks beneath. This surface is:

A great unconformity, with sedimentary rocks above resting on older sedimentary rocks below. NOTE: John Wesley Powell, of the United States Geological Survey, and the leader of the first boat trip through the Grand Canyon, called the feature marked by the yellow lines "The Great Unconformity". It separates horizontal Paleozoic sedimentary rocks, above, from inclined Precambrian sedimentary rocks, below.

Look at the picture above. What happened here?

A great volcanic explosion occurred, spreading material across the landscape and leaving a hole. NOTE: Nature has many ways to make holes, and many other ways to make mountains. Part of this class is learning to read the clues, just as geologists do. We saw at Death Valley that the faults tend to make straight lines. Streams on glaciers are not nearly this big, nor are river bends. And while George is cute, he could never dig such a hole. This is the aftermath of the eruption of Mt. St. Helens.

The ridge left behind by a glacier that outlines where the glacier had been is called:

A moraine, composed of till (which is unsorted) and outwash (which is sorted). NOTE: The beautiful moraines of Cape Cod, Long Island, Moraine State Park in Pennsylvania, Kettle Moraine State Park in Wisconsin, and elsewhere include unsorted till and sorted outwash.

The picture above shows:

A right-side-up dinosaur track.

The pink arrows point to a barrier beach, formed when waves fromthe ocean (on the left) washed away mud and piled up sand, after themud and sand were delivered by the stream flowing in from the upperright. The yellow arrows point to interesting features.How did they form?

A storm broke through the barrier beach and pushed sand farther inland. NOTE: Barrier beaches are piled up by waves, but especially strong storms often break through the beaches. Some of the sand at such new inlets is moved toward the land, often forming new beach-like deposits such as those indicated by the yellow arrows. Some sand is also often moved offshore into deeper water. The river would have buried or reworked the yellow-arrowed features if the river flowed over them, there is no sign of a sinkhole, and bars in the river can be seen to be lower and elongated, not on top and transverse as the yellow-arrowed features are.

Look at the picture above. What type of volcano is this?

A subduction-zone-type, steep andesitic stratovolcano NOTE: This is Lassen Peak in Lassen Volcanic National Park, northern California. Lassen erupted between 1914 and 1921, near the south end of the Cascades chain of subduction-zone volcanoes, and was made a national park in 1916. Hot-spot volcanoes aren't as steep, plateau basalts cover state-sized areas with very flat-lying flows, cinder-cone volcanoes are much smaller, and George's piles are smaller yet.

Oxygen (O2) and nitrogen (N2) do not have much greenhouse effect, but several trace gases including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and various chlorofluorocarbons are important greenhouse gases. The primary mechanism by which these greenhouse gases warm the Earth is:

Absorbing some of the infrared radiation emitted from the Earth. NOTE: Although it is true that squeezing air warms it, the pressure does not set the temperature (change in pressure brings change in temperature), and, the greenhouse gases are really very rare and don't affect pressure much. The production and breakdown of the greenhouse gases roughly balance energetically, and any slight imbalances are tiny compared to the radiative effects of the gases. Convection currents are blocked by the glass of greenhouses, but not by greenhouse gases. But CO2 does absorb some of the infrared radiation emitted from the planet. Absorbing an infrared photon puts a CO2 molecule into an excited state, and fairly quickly the molecule returns to its unexcited state by emitting a photon of the same energy. Some of those photons emitted by excited CO2 molecules head back toward Earth (the emission direction is random). So, the CO2 serves to trap energy in the Earth system, warming the planet so that it glows more brightly to shove infrared radiation past the CO2, achieving a new balance.

Air moves in from the Pacific, over the Sierra Nevada (a mountain range), and down towards Death Valley. What happens?

Air moving down the east slope toward Death Valley is compressed, and warms by about 5 degrees F per thousand feet downward. NOTE: As the air moves down, it is compressed and warms, by about 5 degrees F per thousand feet downward.

What is accurate about the planet's climate system?

Almost the same amount of energy is received from the sun as is sent back to space, but shortwave radiation is received and longwave radiation is sent back to space. NOTE: Energy in equals energy out, to very close approximation. We actually send back the tiniest bit more, because the Earth makes a little energy radioactively and because we are mining stored energy (fossil fuels) and burning it, and some of that goes to heat the atmosphere but some is lost to space. But, these differences are tiny tiny tiny. (Lie in the sun on the grass on a hot day, and see if you can tell whether the sun or the Earth is supplying the most heat to your skin...). We receive shortwave—visible light—and send back longwave—infrared.

Transitional forms between distinct types (species) of different ages in the fossil record:

Are common for commonly fossilized types, but rare for rarely fossilized types. NOTE: Most living things are recycled, not fossilized. Most of the world is eroding, so no fossils are made in most places. Where fossils are being made, only a few percent of living types typically end up producing fossils. And in those few types, new species often appear in small, isolated populations. But careful search has shown many, many transitions in commonly fossilized types. In rarely fossilized types, transitions are much rarer. Lots of people refer to transitional forms in debating evolution. Anti-evolutionists often claim that transitional forms are unknown. When transitional forms are demonstrated, the anti-evolutionists usually argue that all known transitions are "micro-evolution" which somehow is not "real" or "macro-evolution". Because some transitions will always be missing, there is no way to show every possible transition in the fossil record, so this anti-evolutionist argument can't be totally disproven. But that does not make this argument a good one.

Tsunamis:

Are like tornadoes; they can be predicted with some accuracy seconds to hours before they strike in most cases, allowing quick warnings to save many lives. NOTE: Because tsunamis are triggered by earthquakes, among other things, and we cannot predict earthquakes accurately, we cannot make months-in-advance predictions of tsunamis. The p-waves from the earthquakes that cause the most common tsunamis move much more rapidly than the tsunamis do, allowing timely warnings; however, because the tsunamis get where they are going in hours or less typically, not much time is available. Water does go out before rushing in along some coasts, but comes in before going out along other coasts, waves have "up" and "down" parts, and some coasts get an "up" first while other coasts get a "down" first. Little earthquakes make little tsunamis; big earthquakes make big tsunamis.

Weathering attacks a granite in Pennsylvania or Washington, DC, or a similarly rainy place. The quartz grains in the granite primarily:

Are loosened from the rock but don't change much, staying in the soil as quartz sand. NOTE: Quartz dissolves just a bit, freeing silica that washes to the ocean to be used in shells. But most of the quartz hangs around in the soil as quartz sand.

Continents:

Are the "unsinkable" part of the solid Earth; although a little of a continent might go down, most continental material stays near the surface. NOTE: "The Unsinkable North America" might not make it as a vehicle for show tunes, but continents have floated around for 4 billion years and are unlikely to sink in the near future. Old, cold sea floor can sink into the mantle, but continents are lower in density than sea floor and cannot follow. A continent could sink into a subterranean lake of Pepsi One if such a thing existed, but no such thing exists.

What geological processes have caused the Grand Canyon to be wider at the top than at the bottom?

As the river cuts down, the steep walls of the canyon experience mass movement (rocks fall, slump, creep or otherwise move off the walls and down to the river), so the top of the canyon is widening as the river deepens the bottom. NOTE: The tourist suggested that the river has gotten narrower over time. Dr. Alley asked the tourist whether he would ever consider going out on a particular narrow pillar of rock (already teetering dangerously and separated from the walls of the canyon by a huge crack) with a few hundred of his closest friends, and jumping up-and-down vigorously. Predictably, the tourist said "of course not, it might fall over." Dr. Alley then pointed out the many places where rocks clearly had fallen off the cliffs and moved downhill, at which point the tourist quickly switched his opinion to the "down-cutting" river explanation, with the ranger thoroughly enjoying the show.

Regions with mountain glaciers that experience much surface melting in the summer typically are eroded:

At a faster rate than regions with streams but no glaciers. NOTE: Yosemite Valley, Glacier National Park and other glaciated regions still bear the unmistakable marks of glaciers despite more than 10,000 years of modification by streams. Glaciers experiencing melting change the landscape faster than streams do.

The recent changes in the amount of ice on Earth over time occurred:

At regular and repeating times, controlled by redistribution of sunlight on the surface of the Earth in response to features of Earth's orbit, even though total sunshine received by the planet didn't change much. NOTE: The orbital changes have little effect on the total sunshine, but do move that sunshine around, with important consequences. And the orbital changes are far from random, having very strong regularities. We'd love to have seen flocks of ptarmigan and herds of marmots, but no one has found their bones, so it is highly likely that they did not exist.

Which is the correct age progression, from younger (first) to older (last)?

B, F, E, D, C NOTE:The package of sediments C, D, E, F is upside-down, as shown by the footprints and mud cracks, so C is oldest, and F the youngest of these. B is above the unconformity above all of C, D, E, and F, so is the youngest of these five.

Which of the following is not expected very often near a "textbook" subduction zone (that is, near a subduction zone that is so perfect and free of confusing complications that you would use it in a textbook to teach students)?

Basaltic hot-spot volcanoes such as Hawaii.

Some natural resources are renewable—nature produces them fast enough that humans can obtain valuable and useful supplies of a resource without depleting it. Other natural resources are nonrenewable—if we use the resource at a rate fast enough to matter to our economy, the resource will run out because use is much faster than natural production. What do we know about oil and coal?

Both oil and coal are nonrenewable resources, and at current usage rates and prices similar to today, oil will run out in about a century and coal will run out in a few centuries. NOTE: There is lots more coal than oil; oil has this habit of floating on water, thus rising through rocks and escaping to the sea floor where the oil is "burned" for energy by bacteria or other creatures. The size of the resource, in coal, oil, or anything else, depends on the price, and how long the resource lasts depends on rate of use, which is increasing rapidly for fossil fuels. The idea that immense pools of oil are out there, undiscovered but easy to get, is pretty silly—oil companies are really smart, drilled the easy stuff early on, and are now running out of oil that can be drilled and produced at prices close to modern.

You are the chief biodiversity officer for the National Park Service in the eastern US, responsible for maintaining as much diversity as possible, and your boss has told you to focus on maintaining biodiversity of things big enough to see with the naked eye (so you don't need to worry about microorganisms). You have two parks, and enough money to buy 10,000 acres of land. You may add the 10,000 acres to one of the parks, add 5,000 acres to each park while leaving them as isolated parks, or buy a 10,000-acre corridor connecting the two parks. All of the land for sale is now wilderness, but the land you do not buy is going to be paved for a super-mega-mall. You would be wise to:

Buy the corridor connecting the two parks; this keeps one big "island" rather than two smaller ones, and so keeps more species. NOTE: Remember the terrarium—you will have more diversity in an undivided terrarium than in a divided one. Your park area is your terrarium; keep it undivided. Malls have low biodiversity.

During the most recent ice age:

Central Pennsylvania was just beyond the edge of the Canadian ice. NOTE: This is just a fact of geography as described in the text; central Pennsylvania was near but beyond the edge of ice coming from the north. The last option, "no one knows", is the last refuge of lazy minds, and not at all correct.

Many of the headstones in graveyards are made of granite. What are these granite headstones turning into?

Clays, rust, and sand that go into making soil beneath them, and ions that wash away.

Which formula describes the chemical changes that occur and release energy when you start with plant material and then burn it in a fire or "burn" it in a stomach?

CH2O + O2 → CO2 + H2O NOTE: CaCO3 is shell or cave-rock; the equation with CaCO3 on the left is dissolution of rock to make caves, and the equation with CaCO3 on the right is formation of shells. CH2O is a pretty good estimate of average plant composition; the equation with CH2O on the left is burning of plant material for energy, and with CH2O on the right is how plant material is made. Diet Coke plus Mentos does produce an interesting effect, but this is not the way plants grow.

You watched online as Dr. Alley carved a sand canyon with his finger. Based on what you saw, and on what you know about slopes, stability, mass movement, etc., if a landslide happened someplace last week, you would tell the neighbors:

Care is required; landslides are removing instabilities and moving things towards stability, but a second landslide, or a flood, or other problems are real possibilities. NOTE: When Dr. Alley made a "landslide", others often followed, but not always. Similar behavior is often observed in nature. The Gros Ventre slide near the Tetons dammed a river, with dam failure later releasing a flood, but a flood was avoided at Hebgen Lake outside of Yellowstone. And so far, we don't think that America's Funniest Classroom Videos is handing out megabucks. But let us know if they start.

The United Nations, under the auspices of the Intergovernmental Panel on Climate Change, has attempted to assess the scientific understanding of how greenhouse-gas emissions will affect the climate, and thus people. The UN reports show that if we continue on our present path, burning fossil fuels at a faster and faster rate:

Climate will change, primarily getting warmer, and those changes will primarily hurt poor people in warm places, but the climate changes are primarily being caused by wealthier people in colder places. NOTE: Blizzards play havoc with airline travel, which hurts the economy in the mid- and high-latitude wealthier countries. If you have winter (so that warming reduces blizzards), air conditioners (so you can keep the economy humming when the weather is otherwise too hot), and bulldozers (so you can build sea walls or haul things out of the way as the ocean rises), a little warming might even help your economy, although too much warming will be bad. If you are missing any of winter, air conditioning, or bulldozers, all warming is likely to be bad. Most of the world's people are missing all three, and will be hurt by warming, but the warming is being caused primarily by people who have all three.

Which of the following is not a hazard often associated with a single large, explosive volcanic eruption?

Climatic warming. NOTE: This is one of those interesting cases where "slow" and "fast" are different. Volcanoes release carbon dioxide, and carbon dioxide warms. But carbon dioxide stays up a long time, and no single volcanic eruption puts up enough carbon dioxide to make a detectable difference to the concentration in the air and the temperature of the Earth. However, a single big eruption can put enough material into the stratosphere to block enough sunlight to cool the Earth by a degree or two for a year or two. So the climatic hazard from a single big volcanic eruption is cooling, not warming. Explosive volcanoes are often large and steep, and may have huge glaciers. As heat melts the ice, and as melted rock moving into the volcano bulges the sides, huge landslides and mudflows happen. Tens of thousands of people have been killed in single mudflows. Well over 100,000 people live on the deposit from one old mudflow from Mt. Rainier (and those who know about that Osceola Flow really hope it doesn't happen again!). A tsunami is a big wave, caused by an earthquake, landslide, meteorite impact, or volcanic eruption that displaces sea water. Waves can be 100 feet high or more, and do incredible damage. A big eruption underwater can push a lot of water out of the way, making a tsunami. Pyroclastic flows are major volcanic hazards, and can kill lots of people quickly. Imagine a few-hundred-degree mixture of pulverized rock, glass and poison gas chasing you at a few hundred miles per hour! Volcanoes do put out poison gases, such as hydrogen sulfide or carbon dioxide (a little is good; too much is deadly!). When rocks melt a little, fluid- and gas-making materials preferentially end up in the melt rather than in the remaining rock, so eruptions commonly come with gases, and some of those gases are of types or in concentrations that are not good for nearby humans.

Among fossil fuels:

Coal is made by heating of woody plant material, and oil is made by heating of algae. NOTE: Slimy algae gives slimy oil; chunky wood gives chunky coal. Works great. Duct tape and WD-40 are the quick-fix tool kit; if something moves but it shouldn't, apply duct tape, and if something doesn't move but it should, apply WD-40. None of you would be so bad as to merit coal in your stocking, but we presume Santa gets it from a mine somewhere.

What cause probably was not important in contributing to extinction of most species on Earth, including the dinosaurs, in a very short interval of time at the end of the Mesozoic Era?

Cold from the change in Earth's orbit caused when the meteorite shoved the planet farther from the sun. NOTE: Robert Frost once wrote "Some say the world will end in fire, some say in ice". For the dinosaurs, both were probably true, with acid thrown in. But the meteorite was not nearly big enough to change the planet's orbit noticeably. Frost went on "From what I've tasted of desire, I hold with those who favor fire, But if it had to perish twice, I think that for destruction ice, Is also great, and would suffice."

Most U.S. beaches are shrinking or encroaching on the land rather than growing or moving seaward, so the land of the U.S. is getting smaller, not bigger. Which of the following is a likely cause for loss of at least some of our beaches:

Dams have blocked sediment transport to the coast, so there is less sediment available to build beaches. NOTE: As sea level rises, beaches are pushed landward unless something happens to offset this tendency. Dams keep sediment away from beaches, as do the bays formed by post-glacial sea-level rise, and human-caused subsidence of the land is an important problem. But land rising would make for more land, not less.

Glaciers move by:

Deformation within the ice, and sometimes sliding over materials beneath or deformation within materials beneath. NOTE: Deformation within the ice is essentially the definition of a glacier, so that is always present. When the bed is warmed by heat from the Earth, the ice can slide over materials beneath, and may also deform till beneath.

Which of the following is part of the modern theory of evolution?

Diversity exists within a species, and "experiments" that tend to promote diversity sometimes occur during reproduction. NOTE: No matter how hard you and your friends wish that your children will be born with the ability to fly unassisted, the kids will have to use airlines like the rest of us. You can get a tattoo without worry that your children will be born with that same tattoo. A hopeful monster would have no one to mate with. And while sometimes bigger or more-complex kids do better, sometimes smaller or simpler ones do better. But, biological "experimentation" promoting diversity does occur, providing the variability on which natural selection occurs to cause evolution.

The volcanoes of the island of Hawaii eventually will:

Drift off the hot spot and cease to erupt, while a new volcano grows to their southeast. NOTE: As they drift off the hot spot, the Hawaiian chain volcanoes lose their source of melt and quit erupting. But, a new volcano grows. Indeed, the new one, Loihi Seamount, is already there and erupting underwater, building toward the surface. As they cool and sink, and are eroded, the Hawaiian volcanoes disappear below sea level. Hawaiian volcanoes are "friendly", not having highly explosive eruptions. Yellowstone is an anomaly; the hot spot is not making a huge amount of melt, and that melt is modified in coming through the continent, so Yellowstone explodes despite being a hot spot. But most hot-spot volcanoes are not highly explosive. The "protective" layer of condominiums is developing in parts of Hawaii, but lots will happen to the volcanoes in addition—earthquakes and eruptions and drifting and more—and wait until next time when we learn about sides falling off!

To get gas from the Marcellus shale, drillers:

Drill into and then along the shale, and then pump in high-pressure fluids to fracture the rock and release the gas. NOTE: Fracking involves raising the pressure in holes drilled into and along the shale layer, by pumping in water with special chemicals, and this breaks the rock to release the gas. It is still possible that some water wells have been contaminated by leaking gas, but this is not part of the gas-recovery plan.

The picture shows some rocks on the beach at Olympic National Park. The pocket knife is about 3 inches (or 8 cm) long. What is the story of these rocks?

Earthquakes knocked loose undersea muds that raced down the slope into the subduction zone to make these layered rocks, which were scraped off the downgoing slab, part of the process by which continents grow as the scraped-off material is added to their edges at subduction zones. NOTE: Olympic is the pile of scraped-off stuff, and some of it fell into the trench rather recently during earthquakes. Build-up of material above subduction zones contributes to growth of continents over time, not shrinkage. There really are volcanic layers, but as described in the slide show, these are not volcanic layers, and continents grow over time rather than shrinking. Things do wash off freighters, and items such as rubber ducks and shoes have been used to trace ocean currents, but pocket knives sink, and ocean currents are not the driving force for drifting plates. Airline toilets flush into holding tanks on the plane, not onto people or rocks below, and very rarely have pocket knives because the knives are confiscated first.

You get in your Magic School Bus, drive down the throat of a volcano, and find that you are driving through melted rock that flows with much greater difficulty than does most melted rock, because the melted rock you are driving through is lumpier than typical for melted rock. It is likely that the melted rock you are driving through is:

Especially low in water and carbon dioxide compared to most melted rocks. NOTE: The silicon-oxygen tetrahedra link up to make lumps, so anything that gets in the way of this linking will oppose lumping. Iron, water, carbon dioxide, or high heat that shakes the lumps apart can all oppose the lumping of polymerization. Diet Pepsi would break up lumps, too, although isn't especially likely in melted rock.

In the photo above, Dave and Kym are discussing a model of the Waterpocket Fold in Capitol Reef National Park. The Waterpocket probably formed in the same way as the Front Range of the Rockies. This involved:

Especially warm sea floor in the subduction zone off the west coast rubbed along under western North America and squeezed or wrinkled the rocks, folding them (probably with a push-together fault somewhat deeper under the fold). NOTE: We're still arguing about the West, but it is clear that the west-coast subduction zone, which started with old, cold sea floor going down, slowly warmed as the subduction zone and the spreading ridge came closer together. Warmer sea floor would be more buoyant, and so would sink more slowly, or float better. And that would create more friction, squeezing and rumpling with the overlying continent. As the sea floor warmed, squeezed-up/rumpled-up features developed in the West. So we think this makes sense.

Evolution produces new types, and extinction gets rid of them. The scientific evidence summarized in the text and in class shows that:

Evolution and extinction are usually more-or-less in balance, but occasional mass extinctions reduce biodiversity, and subsequent evolution faster than extinction increases biodiversity until a new balance is reached. NOTE: Numerous extinctions have occurred over the history of the planet, but extinctions have been especially rapid during the short "mass extinctions" including the one that killed the dinosaurs. After mass extinctions, evolution fills the empty niches, increasing biodiversity back to a more-or-less stable level.

Scientists promote the teaching of evolutionary theory, in part to raise new scientists to help use evolutionary theory. How are scientists using evolutionary theory in efforts that can help people?

Evolutionary theory is being used to understand, and help fight, the emergence of antibiotic-resistant diseases and other new diseases, and even to guide thinking in computer science. NOTE: As antibiotic resistance appears in disease organisms, evolutionary biologists are helping doctors find better strategies to keep us healthy. The processes behind evolution—try new things, keep the ones that work, repeat—has been used intentionally for guidance in many human endeavors, including "evolutionary computing" in computer science. Ecologists trying to rescue ecosystems are informed by understanding of the evolutionary processes that made, and are changing, those ecosystems. Even regulations for sport fishing are guided by our understanding of evolution. In the same way as other successful ideas in science, evolution is useful in many practical ways in the real world.

What probably happened to create the two rocks with the orange surfaces, seen in the center of the above picture from Greenland?

Expansion from water freezing in the crack wedged the rock apart NOTE: Frost-wedging is probably the most important process in breaking rocks. Tree roots do crack rocks, but in this case, the root almost certainly would have shoved the rocks farther apart, and breaking rocks doesnt kill trees. The broken surface is colored by lichen, which doesnt look much like paint. And if a volcano made the orange, the orange would be on the outside as well.

When humans build or raise levees along big rivers such as the lower part of the Mississippi, we are likely to cause:

Fields and roads on the flood plain to drop below the surface of the river, because compaction of flood-plain mud will no longer be balanced by sediment accumulation during floods. NOTE: "Long, long, time ago, I can still remember how the river used to mend with mud..." The continuing compaction of the sediment along the lower Mississippi should be balanced by new deposits on top; stopping the new deposits does not stop the compaction, so the surface of the flood plain sinks. Even racing around curves, rivers don't tilt much, and mud compaction doesn't do much to meandering. "With a pink carnation and a pickup truck..."

As water from rain soaks through the soil, the water typically:

Gains carbon dioxide (CO2) from the air and then gains more carbon dioxide in the soil, becoming more acidic. NOTE: CO2 is fairly soluble in water. Rain picks up some in the air, becoming slightly acidic. Lots of things living in the soil emit carbon dioxide, and soils contain a lot of carbon dioxide that helps make water more acidic. Humic compounds are picked up from soil by water, and make the water more acidic.

The interactions at the edges of plates are very important. Which is NOT an interaction that is commonly observed all along the length of one of the edges where two plates meet?

HOTT SPOT NOTE: A hot spot pokes through a plate from below, in some small region. All of the others happen at the long edges of plates.

The Mississippi River:

Has built a delta, which is several miles thick at its thickest point, from near St. Louis, MO to the Gulf of Mexico over millions of years. NOTE:Amazing as it may seem, the Mississippi has been taking the debris from the vast area from the Rockies to the Appalachians, and dumping that debris into the Gulf of Mexico, building a pile of sediment that is miles thick in places and extends from St. Louis to the Gulf. The mud has filled an old crack in the continent from when the Atlantic and Gulf of Mexico opened, but the mud doesn't stop the earthquakes that occasionally occur near the tip of the crack. And as for the Yoo Hoo, Yuck!

Which of the following is part of the evidence that the odd layer marking the extinction of the dinosaurs was caused by a large meteorite impact?

High concentrations of iridium found in the layer. NOTE: We have seen several times that iron and silica are very common, that potassium-40 is also common in many rocks (although it changes to argon-40 with increasing age), and that argon-40 appears from potassium-40 over time and so can be quite common in many older rocks. However, iridium is rare on the surface of the Earth, common in meteorites, and common in the layer.

Which is the oldest fault:

I NOTE: I is cut by J, so I is older than J. And with reference to K, both I and J can be shown to be older than H.

The pictures labeled I and II show fossils from a sediment core collected from the floor of the Atlantic ocean, east of South Carolina. The sediment has not been disturbed by landslides or mountain building or other processes. The pictures were taken by Brian Huber, of the Smithsonian Institution, using a scanning electron microscope. The two samples in the sediment core were separated by the unique layer marking the extinction that killed the dinosaurs.Which is correct?

I is older than the unique layer, and thus sat below the unique layer in the sediment on the sea floor. NOTE: Before the impact, biodiversity was high, as shown in I, which includes fossils from below the unique layer and thus deposited before the meteorite hit. After the impact, most of the living types were killed, giving rise to the limited diversity seen in II from above the unique layer after the impact.

Icebergs float in water and continents float above the mantle because:

Icebergs/continents are less-dense than the stuff they float NOTE: Flotation and buoyancy are driven by density differences. In general, less-dense objects float higher up than more-dense objects would. Sometimes the density differences are due to temperature, sometimes due to composition. In the case of icebergs, water is denser than ice, so ice floats. Similarly continental crust is less dense than the mantle.

Which is accurate about the history of the Grand Canyon:

In the deepest part of the canyon, the river cuts through rocks formed by metamorphism of older sedimentary rocks in the heart of a mountain range. NOTE: The Colorado River is cutting through the metamorphic rocks from the heart of an old mountain range. The sedimentary rocks above are right-side up, and the Kaibab Limestone slants down to the north beneath the rocks of Zion, which are older than the rocks of Bryce, among others. Many unconformities exist in the walls of the Canyon, including the one below the Precambrian sediments and the one above those sediments. The idea of the river narrowing over time was the hypothesis that an interested tourist presented to one of the professors and a ranger at the Canyon a few years ago. When the professor asked whether the tourist would want to go out on a narrow point with a jackhammer, the tourist said no, because the rocks might fall off and slide down into the Canyon. When the professor pointed out the many places that rocks had fallen off and slid down, the quick-witted tourist figured out that the Canyon has been widened by such rockfalls as the river has cut downward.

Most commonly, a hot-spot volcano:

Is basaltic in composition. NOTE: The rising hot rock of hot spots feeds volcanoes. Both sea floor and hot-spot volcanoes come from melting a little of the very-low-silica mantle, pulling out the melt, and freezing it, and so are basaltic (low-silica) volcanoes. Note, though, that a few hotspots (such as Yellowstone) are not basaltic, because the basalt has been altered in getting through the continent. The melt probably started out as something that would make basalt, and indeed, the Yellowstone hot-spot track includes basaltic lavas such as those at the glorious Craters of the Moon National Monument. The hot-spot lavas are runny, and spread easily under the air to make volcanoes with gradual slopes, unlike the steep stratovolcanoes, although the slopes of hot-spot volcanoes are steeper under water because the water cools the lava so rapidly that it can't spread far.

Early geologists did not have radiometric dating techniques, or long layer-counted histories. Instead, they followed William Smith in putting things in order, and then used uniformitarian calculations based on modern rates of processes and observed results of processes in the geologic record. These early geologists, using these techniques, found that the Earth:

Is more than about one-hundred-million years old. NOTE: Radiometric techniques reveal the Earth to be about 4.6 billion years old, but early geologists did not have the sophisticated instruments to measure the trace radioactive elements and their offspring. Working from the rocks, the geologists knew that the age must be in the neighborhood of 100 million years, plus extra time in unconformities and additional extra time in the oldest, metamorphic rocks.

Silica released by chemical weathering is transported by streams to the ocean, where much of it:

Is used by sea creatures to make their shells NOTE: Diatoms, radiolarians, and some sponges are among the creatures that make silica shells, from the silica provided by weathering of rocks on land. Silicate ions do not evaporate easily, and are not very common in the atmosphere. A little bit of sea salt, and anything else small in the sea, does escape in spray (stand by the sea on a windy day and you'll get sponts on your sunglasses), but most of the silica reaching the sea is used there. The "saltiness" of the ocean is a quite different chemical, not silica. Some shells are subducted, many more are scraped off downgoing slabs at subduction zones, but subduction does not occur at mid-ocean ridges, which is where sea floor is made, not where sea floor is consumed. Silica is not a major ingredient of milk, although a little silica in some grasses can cause a lot of tooth wear.

What happens to most of the water that falls on central Pennsylvania's Happy Valley each year (or any similar place, such as Washington, DC or other places with trees)?

It is re-evaporated, mostly after passing through trees. NOTE: Water gives life, and life is very good at using water. When their leaves are out, trees use almost all the rain that falls, and tree roots reach down into the ground and pull up some of the water from cold-season rain and snowmelt. An important amount of water does soak into the ground and flow to streams, but plants still get the majority. Flow across the surface is increasing as we pave the landscape, but most of the land is not paved, and flow across natural surfaces to streams is small. Streams are tiny, so direct rainfall into them is small. And soft-drink plants use only a tiny bit of water compared to total rainfall.

Geological evidence based on several radiometric techniques has provided a scientifically well-accepted age for the Earth. Represent that age of the Earth as the 100-yard length of a football field, and any time interval can be represented as some distance on the field. (So something that lasted one-tenth of the age of the Earth would be ten yards, and something that lasted one-half of the age of the Earth would be fifty yards.) On this scale, how far on the football field would represent the time between the first appearance of abundant shelly creatures and today?

Just over 10 yards. NOTE: If the 4.6 billion years of Earth history are 100 yards, then the 570 million years since the widespread appearance of shelly creatures is a bit over 10 yards. Most of our fossil record is limited to the last 10% of the planet's history. The shells appeared "suddenly"—in a few million years, or a few inches on the football field of time.

Any region of limestone bedrock containing caves, sinkholes, springs, etc. is called:

Karst. NOTE: Karst is the region of Slovenia (formerly in Yugoslavia) that has given its name to places with cave-related features. Many, many geological terms have been borrowed from other languages or places, including "geyser" from Icelandic and "tsunami" from Japanese. Permafrost is permanently frozen ground, Pepsoidal is a neologism for "of or pertaining to Pepsi", and scruty is just a word we made up so we wouldn't have to use Pepsi again. Sounds like some bizarre disease, anyway. "Stay back. I have scruty."

What is accurate about the scientific results learned by counting annual layers in ice cores?

Many tests show that some ice cores have reliably preserved annual layers, and the longest record extends back more than 100,000 years. NOTE: As detailed in the text, ice-core layer counters do a huge amount of testing to be sure that the layers really represent years, and that the counting is as accurate as possible. The longest such record now extends beyond 100,000 years.

In the picture above, the dark stripes on the surface of the glacier are:

Medial moraines, rocks picked up from points where tributary glaciers flow together. NOTE: The rocks are still in/on the ice, so they have not been deposited. Sedimentary layers would be spread over the surface like layers of paint, and mineral segregation would not act on such a huge scale.

You are told that a region has no glaciers. What does the lack of glaciers tell you about the climate of that region?

Melting removes all of the snowfall. NOTE: Anyone from Erie, PA or Buffalo, NY, or many other places, can tell you that a snowy winter does not guarantee a glacier, and anyone from the permafrost of Siberia could add that cold does not guarantee a glacier. The way to prevent a glacier is to melt all the snow that falls.

What sort of rock is pictured above?

Metamorphic; The rock separated into layers as it was cooked and squeezed deep in a mountain range. NOTE: The large crystals, intergrown nature, and separate dark and light layers all point to metamorphism, deep inside a mountain range. Rapid cooling in volcanic eruptions gives tiny crystals, not the big, pretty ones here. You can see the former sand grains or other-sized pieces in sediment and sedimentary rocks. And marmot doo-doo consists of small, dark pellets, akin to big rabbit doots, and usually isn't considered to be rock.

You wander around the world for a while and take pictures of many typical living things. If you then were to follow those living things to see what would happen to them after they die, and they behaved naturally, it is likely that:

Most of the living things would be "burned", combining with oxygen to fuel some other living thing, or would be burned in a real fire. NOTE: Nature is a very efficient recycler, so almost everything that lives is recycled. The recycling is usually achieved through slow "fires" in other living things (including you!), using oxygen. However, sometimes a "real" fire such as a forest fire will do the job.

Major differences between Mt. St. Helens and Hawaiian volcanoes include:

Mt. St. Helens is a medium-to-high-silica, explosively erupting stratovolcano, and Hawaii has low-silica, quietly erupting shield volcanoes. NOTE: The low-silica lava from the Hawaiian hot spot flows easily without large explosions, so the lava spreads out to make broad, gentle volcanoes that look like shields of medieval warriors. Melt a little basaltic sea floor with some water and sediment, and you get silica-rich andesite feeding explosive, subduction-zone stratovolcanoes such as Mt. St. Helens. Hot spots and spreading ridges make low-silica, basaltic volcanoes, which don't explode powerfully. Mt. St. Helens is a stratovolcano, but stratovolcanoes are steep, not broad and flat. Mt. St. Helens was the most active of the Cascades volcanoes even before its big 1980 eruption, and the volcano has erupted many times since the big eruption.

Dr. Alley has helped drill many holes in ice sheets. Special tools can be lowered down the holes on cables, and tracked to learn the shapes of the holes. Initially, the holes are straight up and down. Years later, the holes are bent, because the ice in the ice sheet is flowing. What does it mean to say that the ice is flowing?

Much like rocks in the mantle or iron heated by a blacksmith, the ice is almost hot enough to melt, and deforms as gravity pulls on it, without breaking into loose chunks. NOTE: Materials warmed almost but not quite to their melting point can deform without breaking or melting. We saw this with the great convection cells in the mantle, back in unit 2, and we meet it again with ice. If you list the temperature of the ice in degrees F, it is a lot colder than the mantle, or iron heated by a blacksmith, or a chocolate bar in your pocket. But, the ice has been warmed from absolute zero almost to the melting temperature, just like the mantle and the iron and the chocolate, so the stress from gravity can cause the ice to deform or flow.

In the photograph above, a portion of cliff about 30 feet high is shown.From what location in the Grand Canyon did Dr. Alley take this image?

Near the bottom, where the river has cut through rocks that were cooked, squeezed, and partially melted deep in an old mountain range. This is the Vishnu Schist and Zoroaster Granite, rocks from the heart of a mountain range. The river is just barely out of the picture to the bottom.

In the map above, blue shows the Mississippi River, and the Gulf of Mexico, around the Birdfoot Delta of the river. The USGS image uses different colors to indicate changes in the delta. Orange and red both indicate change in one direction, whereas yellow and green indicate change in the other direction.Based on the material presented in this class:

Orange and red indicate loss of wetlands over time, whereas yellow and green indicate gain of wetlands over time. NOTE: The Mississippi Delta is sinking below the waves, so the widespread orange and red must indicate loss of wetlands.

Suppose that the sun suddenly became a little brighter, which would warm the world a little. Over the next few hundred years, what would you expect to happen?

Other things would change in the Earth system, and these feedbacks would amplify the warming from the sun a little and cause the Earth to end up somewhat warmer than before the sun changed.

You start with some of the right kind of dead material, and heat this material in the right way, perhaps with a little squeezing. As the material changes, you end up with coal, and the name scientists give to the material changes. In order, from coolest (first) to warmest (last) the names given are:

Peat, lignite, bituminous, anthracite. NOTE: This is mostly memorization. But the names hide a lot of history, the peat-bog cutters of Ireland, the brown lignites now being mined in Wyoming, the deep-mines and strip-mines of the bituminous coals of western Pennsylvania, West Virginia and elsewhere, and the hard-coal anthracite of the Scranton and Wilkes-Barre region. If you don't know any of this history, you might consider reading up on it a bit; it is fascinating.

Many plants are hard to get along with. Imagine crashing pell-mell through a thicket of devil's club (pictured above),in coastal Alaska, to get away from a charging brown bear. The native people use devil's club for medicinal purposes.

Plant protection by thorns is supplemented by chemicals that are poisonous to many things that would eat the plants; those chemicals are sometimes harmful to humans (poison ivy, for example) but sometimes beneficial to humans, and have given us many of our medicines. NOTE: Most plants have physical protections of some sort (hairs, thorns, hardened parts, bark, etc.), but almost all plants have chemical defenses. Those chemical defenses may kill us if we eat too much, but they may kill microbes that would kill us before the chemicals kill us. A whole lot of our medicines have come from plants, and there undoubtedly are more to be discovered. There is a race on to find those new medicines before we exterminate the plants containing the medicines. Devil's club has been around longer than Pepsi has.

Extinctions have occurred throughout Earth's history. What is accurate about the history of extinctions?

Prehistoric humans cause extinctions faster than is typical naturally, and modern humans are also causing extinctions NOTE: Extinction has happened naturally, but humans have greatly accelerated the rate. Early humans caused extinctions, and so have modern humans, with real worries that the rate of extinction will accelerate a lot more in the near future.

What tectonic setting is primarily responsible for producing Mt. St Helens?

Push together subduction NOTE:Mt. St. Helens sits above a subduction zone, where one tectonic plate goes below another as they come together.

The arrows point to an interesting feature, high in a road cut in the folded Appalachians of western Maryland.What happened here?

Push-together forces broke a layer during folding and shoved one side over the other side. NOTE: It is always shorter around the inside of a curve than around the outside, a fact well-known to NASCAR drivers and wannabees. The rocks above were folded in the great collision that made the Appalachians, which tends to stretch the rocks on the outside of the curve (near and below the bottom of the picture) and squeeze the rocks on the inside. If the rocks are brittle and don't "want" to flow, they may break, giving patterns such as that shown by the arrows. You can see similar things in many places; if you happen to visit Penn State's University Park campus, such features are exposed in the road cut along the Rt. 322 expressway just southeast of East College Avenue.

What tectonic setting is primarily responsible for producing Olympic National Park as well as the hills on which San Francisco is built?

Push-together subduction NOTE: The rocks of Olympic and San Francisco were scraped off the downgoing slab of the subduction zone.

In age dating, geologists use:

Radiometric techniques and layer-counting for absolute dating of events that happened in the last 100,000 years, and other radiometric techniques for absolute dating of much older events. NOTE: If you want an absolute date (number of years) rather than older/younger, you can count layers for young things, or use radiometric techniques for young things or for old ones.

Hot Spots:

Rise from as deep in the mantle as the core-mantle boundary to the surface of the Earth, bringing up heat and feeding volcanoes. NOTE: Earthquakes make sound waves that go through the whole Earth, and go slower through hotter, less-dense rocks. By putting out listening devices called seismometers around the Earth, and listening to the waves from many earthquakes in many places, scientists can map the hotter regions, and find that towers of hot rock come up from way deep in the Earth in some places. But, some other hot spots don't seem to start as deep. The hot spots don't seem to move around much, but the lithospheric plates drift around over the hot spots. Hot spots come up beneath continents and oceans, and can poke through both. No one has ever found caffeine in a hot-spot plume, although it is possible that other things stir up trouble in Congress.

Geologically speaking, the water table:

Rises during or soon after rainstorms as spaces fill up, and sinks during droughts as water drains away. NOTE: As trees suck up water during droughts, air enters spaces where water once was, so the water table (which is the bottom of the region with some air in spaces) must sink in elevation. Creeks do change in elevation between rain and drought (floods happen...), and while there are random elements in the world, this is surely not one of them. (Whenever someone claims something is random, at least suspect that the person is really saying "I don't know what I'm talking about, and I'm too lazy to find out.") And while there might be bottled water in the Capitol, geologically speaking, that is not the right answer.

In the two pictures above, I and II, show traces of former life in rocks from the Grand Canyon. Each is "typical";the rocks near sample I contain fossils similar to those shown in sample I, and the rocks near sample II contain fossils similar to those shown in sample II.It is likely that:

Sample I is from higher in the cliffs of the Grand Canyon, and sample II is from much lower, nearer to the river. NOTE: Sample 1 shows shells from complex creatures including trilobites and snails, from the Supai Group far up the side of the Canyon.

Acadia is beautiful even in the rain and fog, but the park still doesn't have many sandy beaches, and this is surely not a sandy beach, the rocks are granite, broken off the granite bedrock. Why aren't there sandy beaches?

Sand is produced or supplied slowly enough, and sand loss to deep water is fast enough, that sandy beaches do not form. NOTE: Granite does weather to make sand, so some sand must be produced, but this is not a sand deposit, so sand loss must be fast enough to prevent large accumulations. The Park Service would not allow sand mining, and New Jersey would just go offshore to deeper water to dig up sand. And huge storms hit Florida and the Gulf Coast, but they have sandy beaches.

Sometimes, science and religion come into conflict. This is because:

Science and religion can coexist just fine with a little effort, but sometimes choose not to do so. NOTE: Pope John Paul II said that the Catholic Church has no problem with evolution, and Baptist Jimmy Carter also supported evolution, so it is clear that religion and science can agree.

Years may pass with no major damage to the US mainland from hurricanes, but other years bring huge damages. A terrible event happened in 2005, when levees around New Orleans failed in the rising waters of Hurricane Katrina. More than 1400 people died, and the damages were in the neighborhood of $300 for each person in the US, or about $100 billion. As discussed in the text, history shows that:

Scientists and serious planners had warned about such an event for decades, based on the known size of hurricanes and the sinking of the Mississippi Delta and much of New Orleans. NOTE: Scientists and planners did not know exactly when a big hurricane would hit New Orleans and threaten the city, but serious assessments had consistently highlighted the possibility for decades. The failures at New Orleans happened despite the fact that Katrina was NOT the "Big One"—on a scale of 1-5, Katrina was a 3 when it made landfall.

The picture above is of the coast at Acadia National Park. Look at the shape of the rocky island marked with the big "I" in the middle of the picture.The most likely interpretation is that this was caused primarily by:

Sculpting of the rocks by a glacier, which flowed from the left to the right. NOTE: The side of the rock that a glacier reaches first is sandpapered and rounded blocks are removed. The ice thus flowed from left to right, streamlining and smoothing the island. Wind and waves do not make such distinctive forms, and while Rockefeller stonemasons might have done so, they probably would have carved a huge likeness of a fabled ancestor instead.

On average around the world:

Sea level is rising, as warming causes ocean water to expand, and glaciers to melt. NOTE: Indeed, sea level is rising, by almost an inch per decade. The biggest reasons are melting of ice on land that releases water that flows into the ocean, and expansion of ocean water as it warms up.

In the picture above, the big W is in ocean water, while the little w is in water in a bay cut off from the ocean by the bar indicated by the pink dashed arrow. A stream flows toward the bay along the blue arrow, and coastal bluffs are indicated by the dashed yellow arrow.What probably happened here?

Sediment has been eroded from the land by waves crashing against the bluffs, and the sediment has been transported along the shore by longshore drift to build the bar. NOTE: Longshore drift is important, and moves much sediment. The greater width of the beach across the mouth of the stream than nearby shows how far waves can go; adjacent to the stream, the waves must cross the beach during storms and batter the bluffs, making sediment that feeds the longshore drift. Submarines are not a big worry in such shallow, near-shore settings, and sinkholes tend to be round, not elongated as seen here.

Humans often try to change coastal processes to benefit us. One of the many things we do is to build walls, or groins, or jetties, to interrupt waves and currents and sediment transport. This example is from the coast of Washington.What has happened here?

Sediment transport is typically from the right, causing deposition to the right of the jetty but erosion to the left NOTE: A jetty works like a dam, trapping sediment on the "upstream" side and letting clean water pass to the other side, where the clean water erodes. So, the transport is typically from the right. A large beach has been formed there, but erosion "downstream" is cutting around the end of the jetty.

A dam is built on a river, forming a reservoir. Over time, this likely will cause:

Sedimentation to bury farmer's fields upstream of the reservoir, and erosion of sand downstream of the dam. NOTE:The stream will slow where it enters the new lake, and so will deposit sediment to form a delta rather than cutting downward or having no change. As the delta builds out into the lake, the upstream end of the delta must build up so that the stream still slopes downward, and this will tend to bury fields upstream. Meanwhile, moving water can carry sediment. Sediment-free water is released from a dam but often later observed to have sediment, so erosion must be occurring. Loss of sand bars below the Glen Canyon Dam shows that sand is carried away downstream of dams. Dams stops floods that are needed to move the big pieces (boulders, cobbles), and dams cause sedimentation upstream, but not downstream. Our friends from Columbus are probably too cultured to be relieving themselves outside the Mall; besides, the last time I looked during a visit from the Buckeyes, the inebriated people were not straying that far away from the downtown bars.

Evidence that there was much more land ice about 20,000 years ago than there is now includes:

Shells of creatures that lived in the ocean about 20,000 years ago indicate that the ocean water was especially isotopically heavy then. NOTE: The land with the unique glacier marks was pushed down by the ice and now is bobbing back up, water returned to the oceans from the melting ice caused sea level to rise so that river valleys were drowned and are filling up with sediment, and so that shallow-water corals were left far below sea level, but taking light water out of the oceans to grow ice sheets causes the remaining waters, and the shells, to be isotopically heavy.

Mt. St. Helens sits above a subduction zone, where one tectonic plate goes below another as they come together.

Slide-past motion along a great fault. NOTE:Not much mountain-building is happening along the central coast of California; the rocks slide past horizontally. The sliver of California to the west of a line connecting San Francisco to Los Angeles is sliding to the northwest, and as the sliver slides, it sticks and slips, making earthquakes.

There are many large mammals on Earth today. This is because:

Small mammals were not able to outcompete the dinosaurs for big-animal jobs, but after the dinosaurs were killed, some large mammals evolved from small mammals to fill the large-animal jobs. NOTE: There are "big-animal" jobs—eating tall trees, eating smaller animals, etc. But the total number of big-animal jobs is limited. The dinosaurs filled the big-animal jobs before mammals really got going, and mammals were not able to displace the dinosaurs. Some small mammals survived the meteorite that killed the dinosaurs, and then evolved to give big mammals over millions of years and longer. There were almost no big mammals before the dinosaurs were killed off, volition has nothing to do with evolution, and running away doesn't avoid acid rain.

In the picture above, the pink and yellow arrows in front of Dr. Alley point to two rather different deposits from an eruption of the Hawaiian Volcano Kilauea. As described in the class materials, these materials are:

Small pieces thrown through the air, and frozen "waterfalls" of lava that flowed quietly before freezing. NOTE: Mt. St. Helens and similar volcanoes make giant explosive eruptions that throw bus-sized blocks, but Kilauea in Hawaii usually doesn't (although rarely, water flashing to steam may move some big things!). Dr. Alley showed you the gravel-sized pieces of glass at the end of the pink arrow, and the frozen "waterfall" of lava at the end of the yellow arrow.

Hardy souls who visit beaches in the winter are often surprised by how different summer and winter beaches really are. A typical change is (note: a breaking wave curls over and the top falls down, making spectacular movie footage if a surfer is in the way; a surging wave hangs together and the top doesn't fall over):

Surging waves bring sand in during summer, and breaking waves take sand out during winter, so summer beaches are large and sandy while winter beaches are small and rocky. NOTE: Winter beaches are eroded, as breaking waves bring their energy far inland through the air, and the outgoing rush of water removes sand; surging summer waves replace that sand. And if you have ever been in a Nor'easter on the Cape, even hardy nudists would be in danger of losing certain important peripherals.

The top picture from the coast of Greenland, and the bottom picture from Bear Meadows Natural Area in central Pennsylvania, are geologically related. How?

The Greenland picture shows rocks that have been creeping downhill on permafrost, and Bear Meadows probably was formed when such a creeping mass dammed a stream during the ice age. NOTE: Indeed, the hillslope in Greenland bears the unmistakable signs of creep on permafrost, carrying streams of rocks and bits of tundra downhill. Geologists are fairly confident that the Appalachians looked like this just beyond the glaciers during the ice age, and that rocks carried downhill this way dammed a stream to form Bear Meadows in central Pennsylvania.

There is a deep trench in the sea floor off the Marianas volcanic arc of explosive, andesitic, Ring of Fire volcanoes in the South Pacific, but the water is not deep off the coast of Oregon and Washington near Mt. St. Helens and the Olympic, because:

The Marianas, Oregon and Washington have had the sea floor bent downward by subduction to make trenches, the trench off Oregon and Washington is filled by sediment eroded from the nearby continent, but the Marianas don't have a nearby continent and so the trench there is not filled with sediment. NOTE: The more rocks there are nearby, the easier it is for erosion to move some of those rocks. The trench off Oregon and Washington has Oregon and Washington nearby, with lots of rocks. Add in that Oregon and Washington have great rivers such as the Columbia, and huge glaciers that grind up the rocks such as the beautiful glaciers on Mt. Rainier, and there is lots of sediment to fill the trench and be scraped off the subduction zone to make Olympic National Park. The Marianas involve subduction of older, colder sea floor under younger, warmer sea floor, have less rock above sea level nearby to be eroded, are in a warm place without glaciers, and so haven't filled the nearby trench with sediment. There probably are a few discarded floppy disks, as well as a lot of other human-produced material, in the trench off Oregon and Washington, but nature has been a lot more important than humans in filling the trenches. Humans did once talk about disposing of radioactive waste in the trenches, but then we found out that whatever goes down the trench comes back up, and may be squeezed and broken and squirted back up quickly, so we gave up on that idea. And the volcanoes of Oregon and Washington are subduction-zone volcanoes, not hot-spot volcanoes.

Beaches change size with every storm, but if you average over a few decades, the size of a typical sandy beach is usually controlled by:

The balance between sand loss to deep water, and sand supply from rivers or from coastal erosion.

People sometimes take machines out into deep water to "mine" sand, and bring it back to beaches. Dumping a lot of new sand on a beach usually causes:

The beach to lose the new sand over the next year or years, as waves and currents move the sand back to deeper water. NOTE: Waves and currents move lots of sand. If we want to offset this, we need to move a lot of sand, too. Building beaches from mined sand can work, but the sand heads back to deep water quickly, so in most cases the activity must be repeated every year or every few years to keep the beaches large and sandy.

The picture above illustrates what scientific principle?

The equator is hotter than the pole because the sun hits the equator directly but the sun hits the pole a glancing blow NOTE: Geometry is the main control on equatorial heating. Although the equator is closer to the sun than the pole, the difference is tiny and matters little to the temperature difference between equator and pole. The rotation of the Earth causes winds to turn as they blow over the surface, but does not heat the air. There is no clustering of volcanoes at the equator, and the heat from volcanoes is tiny compared to the heat from the sun. And we are quite confident that several celebrities and politicians believe that they are the worlds sexiest human being, so Dr. Alleys standing cannot be undoubtedly claimed.

The cartoon above illustrates a specific geologic process. In which of the additional images can the same geologic process be seen?

The folded Appalachians, including the region of central Pennsylvania around Penn State's University Park campus, shown in the satellite image here, formed when Africa and Europe collided with the Americas, much as the two cars in the picture collided. Death Valley, Crater Lake, and George the Immense Marmot record different processes.

The picture above shows a glacier in eastern Greenland, in the world's largest national park, flowing from mountains at the top of Jameson Land (at the top of the picture) toward the lowlands of Kong Oskar Fjord (just out of the picture at the bottom).Based on what the picture shows, what has happened over the last century or so?

The glacier has become shorter, because of a decrease in snowfall to the accumulation zone (A) or an increase in melting of the ablation zone (B). NOTE: Accumulation is a building up, ablation a wearing away or loss. The glacier builds at high elevation (A) and wears away at low elevation (B). And, the halo of moraine around this glacier at low elevation shows that the ice has retreated, so a decrease in snowfall to the accumulation zone or an increase in melting of the ablation zone is indicated.

In the photo above, Sam Ascah is standing on sand and gravel in a pothole, where a stream swirls during the short but intense thunderstorms of Zion National Park. And next to that stream, the other picture shows the sandstone and the hang-on-so-you-don't-fall-over-the-cliff chain along the trail. A likely interpretation of these features is:

The grooves behind the chain have been cut over decades by motion of the chain as hikers grabbed it, and the potholes were cut by water swirling rocks around during the rare floods over much longer times. NOTE: The chain really has hung there for decades, and has been scraped against the cliff dozens of times per day each summer, slowly wearing into the easily broken sandstone. The stream does swirl rocks around and slowly wear down the potholes. The potholes were there beside the cliff when the trail was established, and havent changed too much over decades.

Air that passes over the Sierra Nevada from the Redwoods to Death Valley is warmed by roughly 30oF, even if the air goes over at night. Where does the energy come from?

The heat that had been stored during evaporation of water from the ocean and was released when condensation made clouds and rain over the Redwoods. NOTE: Much of the sun's energy that falls on the tropics is stored by evaporating water, and only later made so you can feel it (called sensible heat) when condensation reverses the evaporation. Winds are driven by pressure differences, and do curve in response to the Earth's rotation, and there is a little bit of heat generation from friction, but you should probably know that standing outside in the wind does not make you hot as the frictional heating occurs around your body—the frictional heat is very small. (If the air were moving past you at many times the speed of sound, the frictional heat would become large, as shown by meteorites "burning up" in the atmosphere, and the need for heat shields on spacecraft re-entering the atmosphere. And while marmots do produce a little methane, and a bit of heat, they don't produce nearly enough to matter to the climate.

In Pennsylvania today (or at most other places on the world's land surface):

The land surface is accumulating sediment in a few small places, building up records of geologic history, but most places are eroding. NOTE: Today in Pennsylvania (and across most of the land surface of the planet), sediments are accumulating in a few human-made lakes, a few natural wetlands or natural lakes, along some streams and in some caves, but almost everywhere else is eroding. This is the typical state of affairs, so you need to correlate events across large regions to get a good geologic record.

Often, landowners along eroding beaches will build groins, which are walls or dams sticking out into the ocean or lake from the beach. Why are these built, and what happens?

The landowners are trying to catch sediment from the longshore drift to add to the beach; this can work, but often erosion on the "downstream" side of the groin makes the neighbors mad. NOTE: The "river of sand" that is the longshore drift along the beach is similar to a river in many ways. "Damming" the flow with a groin will trap sand upstream, on the side from which water and sand are coming, but that will allow water with less sand to attack the downstream side, causing erosion there. Dense groin networks may actually so roughen the coast that they hold sand overall, but the erode-the-downstream-neighbors problem is real and often dominates. If you wanted to trap sand going in and out, you would build walls or dams that are perpendicular to that motion, and thus parallel to the beach. And groins are not the best places on which to stand during storms, nor do many landowners actually plan ahead to get good pictures of their houses falling apart in the waves.

(4) We now know a lot about the big processes that shape the Earth's geology. Which of the following is NOT correct about that knowledge?

The lithosphere is broken into hundreds or thousands of plates, all of which are very small. NOTE: The lithosphere is broken into a few big plates, plus a small number of smaller ones, but not into hundreds or thousands of very small plates.

What type of mass movement moves the most material, averaged over the Earth's land and over long times?

The many, small events move the most material. NOTE: As rocks move to streams in many places, such as Pennsylvania, the slow and steady motions are more important than the few dramatic events. Specific places may be dominated by the few, dramatic events, especially in steep mountains, but across the Earth soil creep probably dominates.

Dr. Randall Irmis is a famous paleontologist, who has gone on to make important discoveries since he showed the Penn State CAUSE class this fossil plate from the armored vertebrate Buettneria.Based on the discussions in the class materials on the topic of evolution, it is likely that:

The most similar species alive today are related to but recognizably different from Buettneria. NOTE: Evolutionary theory indicates that living things change from generation to generation, but that all living things are related. Consistent with this, Buettneria is recognizably similar to, yet different from, amphibians still alive today.

The United Nations-sponsored Intergovernmental Panel on Climate Change shared the 2007 Nobel Peace Prize. The information that the Panel has supplied to policymakers includes:

The observed rise in atmospheric CO2 levels has been caused primarily by human fossil-fuel burning, and very likely is causing warming of the climate that is likely to become much larger if we continue our current behavior.

The above Landsat image from NASA shows Cape Cod, Massachusetts. This is a pile of sand and gravel out in the north Atlantic. The Cape has no large rivers, and is not especially close to any large rivers (the Connecticut and the Hudson are far out of the picture to the left). Looking along the far right-hand side of the Cape, the long white line is sand of the great outer beach (pink arrow), and sand deposits are prominent to the north and south (yellow arrows).What is going on?

The ocean is eroding the outer beach, and the yellow-arrow ends are growing more slowly, so the Cape as a whole is shrinking. NOTE: You can actually see sand underwater off the yellow arrows, and that sand came from the outer beach—the Cape is losing ground. Furthermore, the Cape is losing ground much faster than nudists are losing peripherals.

Earthquakes can be caused in many different ways. The best interpretation of the planet's earthquakes is that:

The rare, deepest ones are caused by "implosion" as minerals in downgoing slabs of subduction zones suddenly switch to a denser arrangement, whereas common shallower ones are caused by elastic rebound of bent rocks when a fault breaks. NOTE: "Implosion" is the currently favored idea. As subduction zones take rocks deeper where pressure is higher, the building blocks tend to reorganize to take up less space, shifting from, say, a one-on-top-of-another pattern to a fit-in-the-space-between-those-below pattern. Sometimes, this seems to be delayed and then to happen all at once (I can't move until my neighbor does...), giving an implosion. The biggest, deepest earthquakes happen where temperatures and pressures are so high that we don't think rocks can break. Humans have never made a hole anywhere nearly as deep as the deeper earthquakes. We have mostly quit testing atomic bombs. And, coffee shops just aren't buried deeply enough to account for the deepest earthquakes.

Stephanie and Topher are standing next to the Colorado River in the Grand Canyon.What can be said of the water here?

The river was naturally muddy, but has been made clear because most of the sediment is settling out in the reservoir behind the dam upstream. NOTE: Native species that lived in the muddy waters are now in danger of becoming extinct, because the clear water released from the dam makes those fish too easy for predators to see.

The picture above shows a very hard piece of rock about six inches across, in the Grand Canyon.The surface of the rock looks rather different from the surfaces of many other rocks.What made this odd-looking surface?

The river, which blasted the rock with sand- and silt-laden water during floods; this shows that even hard rocks can be eroded by rivers. NOTE: The Canyon was carved by the Colorado River. Glaciers have not been there, and while wind and faults can change the appearance of rocks, none makes something like this river-polished rock, as you saw in one of the Grand Canyon V-Trips.

Shown above is Great Rock, Cape Cod National Seashore, with some of Dr. Alley's relatives for scale. The rock is metamorphic. The picture includes most but not all of the above-ground portion; the rock goes about as far below ground as above. What is the rock doing here in the middle of Cape Cod?

The rock was carried here by glacier ice and left when the ice melted. NOTE: Glaciers carry rocks of all sizes easily. Cape Cod is the product of glaciers, and almost everything natural on the Cape was delivered by glaciers originally. There rarely are big tsunamis in the Atlantic, but not this big. Nor is there any evidence of a big meteorite impact that is as young as Cape Cod. The east coast is rather free of large earthquakes, although Charleston, South Carolina gets a few occasionally. And the early settlers would not have put such a huge thing in the bottom of their ship (imagine having that bouncing around in a storm!), nor could they have taken such a rock out easily upon arrival.

Pieces of bedrock from Canada are spread across large areas of northwestern Pennsylvania, even though the Great Lakes are between Pennsylvania and Canada. How do geologists explain this?

The rocks were carried into Pennsylvania by a glacier flowing from Canada; the base of the ice was able to flow uphill from Lake Ontario into Pennsylvania because the top of the ice sloped down toward Pennsylvania. NOTE: Ice, or pancake batter, or any pile, tends to spread from where its upper surface is high to where its upper surface is low. The Great Lakes are old features, but the base of the ice really did flow up out of the Great Lakes into Pennsylvania because the top of the ice sloped down from Canada into Pennsylvania.

You use highly accurate techniques to learn the time when lots and lots of different volcanic rocks solidified from melted rock. You do this for many different rocks across the continents, and many different rocks across the sea floor. You will find that (note that "older" rocks are those that solidified more years ago, and "younger" rocks are those that solidified fewer years ago.):

The sea-floor rocks are typically younger than the continental rocks, because sea-floor rocks are taken back into the mantle at subduction zones about as rapidly as new sea-floor rocks are produced, while continental rocks are not taken back into the mantle at subduction zones. NOTE:You can find young rocks on the sea floor and on the continents, but all of the old rocks on the planet are on continents—there are no old sea-floor rocks. The older sea floor has all been recycled at subduction zones.

In the image above, a stream from the land on the right enters the ocean on the left in the lower part of the picture, and another does the same near the top of the picture. What happened where the streams met the ocean?

The sediment carried by the streams settled out in the slower-moving ocean water, forming deltas that built up as they built out so that they still slope slightly downhill toward the sea. NOTE: These deltas in a fjord in Greenland are like any other deltas; the deposits cannot be purely flat-topped, or the rivers would not flow across to get to the sea water in the fjord.

Soil is produced by weathering of rocks. In the natural state of affairs, on a hillside covered by soil:

The soil thickness tends to a nonchanging value as production is balanced by removal, but you may have to watch for a while, as sometimes production may go faster and sometimes removal may go faster. NOTE: Naturally, there is a balance between production and removal of soil over large areas and long times, but at any moment in a particular place, production and removal may be out of balance, as during a fast-moving landslide or when a marmot is digging a new hole. Human pets (including orange-and-white Coral and gray Prancer Alley, seen here in a group hug with Eeyore), do affect things but are not major sources of soil.

One practical radioactive system used to date lava flows involves:

The solid potassium-40, which decays to the gas argon-40. NOTE: Potassium-40 is common in solid minerals, and decays to produce the gas argon-40. And despite his great contributions to humanity, no one has named an isotope after moose moss (the favorite food of Thidwick, for you Dr. Suess fans).

The concentration of CO2 in the atmosphere rose as the last ice age ended, and then stabilized for thousands of years, until humans became serious about changing the atmosphere with the start of the industrial revolution. Suppose that we succeed in raising the CO2 concentration in the atmosphere to a level twice as high as occurred for the thousands of years after the ice age and before the industrial revolution, and then we hold the concentration constant at that new, higher level for the next thousand years. What would happen to the average temperature of the planet?

The temperature would increase to a few degrees above the pre-industrial-revolution level, and then stabilize at that new, warmer level. NOTE: The temperature would increase to a few degrees above the pre-industrial-revolution level, and then stabilize at that new, warmer level.

Which is younger:

The tree. The tree is growing on intrusion G, which can be shown to be younger than all of the others.

Statistically, and based on how many people are likely to die if they engage in or are exposed to the following problems, which is most dangerous to residents of the United States:

The various diseases that come from smoking, overeating and under-exercising for a long time. NOTE: There are still meteorites in the solar system that can hit and kill, and a reputable study found that a meteorite impact might not occur for millions of years (or might occur next year...) but then might kill billions. Add up the deaths over a sufficiently long time, and plane crashes (which kill a few to a few hundred people per year) and meteorite impacts likely would be similarly dangerous. Earthquakes and tornadoes, as devastating as they can be, don't kill as many people in this country as do airline crashes. Smoking, overeating and underexercising are way more dangerous to us.

The photograph above shows some rocks in Great Smoky Mountains National Park.From looking at the rocks, and what you know about the park, a likely story is that:

These rocks were buried deeply and squeezed in a continent-continent collision, and then brought to the surface as overlying rocks were eroded. NOTE:The squeezing and heating of an obduction zone have changed these rocks from mud to the folded schist seen here, and then erosion has revealed the rocks at the surface. There were large volcanoes near where the Smokies are before the Smokies formed, but those volcanoes ended when subduction ceased and obduction started to build the Smokies. Some slide-past motion did occur in the Appalachians, but not a huge amount, and the Smokies were not brought up from Florida.

Which is most accurate about tsunamis?

They are big waves caused by very rapid displacement of a lot of water, which may occur in response to an undersea landslide, earthquake, volcanic eruption, or other cause.

The ptarmigan and the marmot have something in common, other than being cute. What is it?

They both are standing on glacially eroded surfaces. NOTE: The carbon-based bird, top, and the carbon-based mammal, bottom, would be unhappy if you accused him of being a silicon-based flatulent amphibians. Moraines and other glacial deposits are composed of small pieces, including till with pieces of many sizes. The striated, polished granites under these cold-climate critters were eroded by glaciers.

Your friend wants to see some real Pennsylvania coals. Where should you send your friend to see coal in the rocks of Pennsylvania (if you honestly are being helpful), and what coals would your friend see?

To the sedimentary rocks of western Pennsylvania to see bituminous, and to the metamorphic rocks of eastern Pennsylvania to see anthracite. NOTE: Bituminous is found with sedimentary rocks, but ones that have been squeezed and heated a bit so they are held together well and are not much like loose sediment; such rocks are common in western Pennsylvania. Anthracite is the most-cooked coal, and is found with metamorphic rocks in eastern Pennsylvania. Pennsylvania has lots of coal, but not much lignite, which would not be found in metamorphic rocks anyway.

Which is older:

Unconformity L NOTE: Unconformity L is cut by fault I, so is older than I. Fault I is cut by fault J, so is older than J. Fault J is cut by unconformity K so is older than K. Unconformity K is cut by intrusion G so is older than G, and intrusion G is cut by fault H so is older than H. Hence, unconformity L is the oldest on this list.

In the picture above, Dr. Alley is discussing events that are happening outside of Grand Canyon National Park, which may impact the park. What are the issues he is discussing?

Water pumped out of the ground for golf courses and other uses evaporates, so less water flows through the ground to the springs of the canyon. NOTE: Water soaks into the ground on the plateaus beside the canyon, seeps down to hit a rock layer that blocks the flow, and flows along that layer to feed beautiful and biologically important springs in the Canyon. Pumping water out of the ground on the plateaus to use for humans generally allows the water to evaporate (say, from the grass of a golf course) or run down a stream (say, below a sewage treatment plant), so the water doesn't flow through the ground to the springs.

Large rivers sometimes have natural levees because:

Water slows and deposits sediment as the water leaves the main river channel during floods. NOTE: The initial slowdown as water spreads into the trees deposits sediment to form natural levees. Sinking mud doesn't make ridges. Point bars are the sand bars on the insides of meander curves, and oxbow lakes are abandoned meander curves, but neither makes the natural levees that are observed.

Much melting in the mantle occurs near subducting slabs primarily because:

Water taken down subduction zones lowers the melting temperature in and near the slabs. NOTE: Throw a little dry flour in a warm oven, and not much happens. Add some water, or better, some water and some carbon dioxide from yeast, and things happen in a hurry. The subduction zone takes water, and carbon dioxide in shells and other things, down to lower the melting point and feed volcanoes. Friction does warm the down-going slabs, but slabs start off way colder than the rocks into which they move, and remain colder for a while. Sliding your cold feet along the sheets when you get into bed on a winter night may warm your toes a little by friction, but if you happen to share the bed with a significant other, putting your tootsies on that persons bare belly will tell you that frictional heating takes a while! The scraped-off pile of sediment traps a tiny bit of heat, but not too much; the downgoing slab makes the nearby mantle colder than normal, not warmer. And nature tends to separate regions where something is flowing one way from regions where the flow is reversed; if the flows are too close together, one will drag the other along and change its direction. Hot spots occasionally ride along on spreading ridges, because both involve rising, but not on subduction zones.

In the photo above, the jetty (which is a big wall, and could also be called a groin) was constructed out from the coast in the state of Washington. The water is shallow very close to the jetty, and deeper as you move away to left, right, or off the end of the jetty at the lower right.Look at the pattern of waves, which tells you that:

Waves go slower in shallower water. NOTE: Waves do go slower in shallower water. Waves coming in from the sea are held up along the jetty, so the crests become more and more curved with the ends nearest the jetty falling behind as the waves move inland.

The mountain range that contains the folded Appalachians, including Mt. Nittany near Penn State's University Park Campus, and the Great Smoky Mountains, was raised to high elevation primarily:

When the proto-Atlantic ocean closed, at a push-together boundary. NOTE: Run a car into a brick wall and the front of the car is crunched and bent. Fly over the folded Appalachians and you'll see the same pattern. There was a little Death-Valley-type uplift next to regions of down-dropping to the east of the Appalachians when the pull-apart happened, but the style of the Appalachians doesn't look like Death Valley, and the mountains were already here when the pulling apart started. We can see that the rumpling from the subduction zone in Oregon extends only 100 miles or so in from the coast, and even the Rockies required a special explanation as to why they are so far inland; the Appalachians are too far away to have been affected by subduction under Oregon. We can see that the Appalachians don't make a circle around a hot spot; they make a long belt parallel to the east coast. The Appalachians are way older than Death Valley, and with the Great Plains in-between, it is clear that the influence of Death Valley does not extend to rumpling rocks near the east coast.

At the beach, you can build really good sand castles:

When the sand is damp, because water is attracted to sand grains and to other water; thus, pulling sand grains apart when damp requires "breaking" the water, which is not easy. NOTE: Any good glue must stick to other things and to itself. If it doesn't stick to other things, the glue just peels off. If it doesn't stick to itself, you can break the glue in the middle easily, separating the things that you just glued, although leaving a little glue on those things. Water works the same way—it sticks to sand grains well, and water molecules are attracted to each other, so that it takes some "oomph" to break apart damp sand grains. Make them fully wet, and the grains can move without "breaking" the water, so the material becomes weak.

Suppose that all the rainfall that fell during an average year on a typical surface in central Pennsylvania just stayed there as a layer of water (and all the snow melted, and the melt just stayed there). If at the end of the year you were standing on your head on that surface (assuming you are a typical-sized human being), what would be true? (In an average year, Pennsylvania gets about the same amount of precipitation as the average for the world.)

You would be breathing by SCUBA or snorkel, because the water would be up between your belly button and your knees somewhere. NOTE: A typical rainfall supplies about an inch of water, or just under 0.1 foot. 30 feet of rain would be a big storm every day, about equal to the wettest place on Earth, and while sometimes it may seem the rain in Pennsylvania will never end, there really are clear days. 0.3 feet is a mere 3 or 4 rainfalls per year, and is a dry desert. 0.03 feet would be the driest place on Earth, and 0.003 doesn't occur on Earth. 3 feet is a nice number, which would be up to your knees or so if you were standing on your head, so you'd need the SCUBA gear.

You develop a new idea, which is in conflict with a widely accepted scientific idea. For your new idea to gain widespread acceptance, you probably will need to show that:

Your new idea does a better job than the previously accepted idea in predicting the outcomes of an interlocking web of important experiments or observations. NOTE: At last observation, Pepsi commercials were not highly scientific, even if science is involved in figuring out what sells. It is a romantic notion that you could overturn great knowledge with a single observation; however, observing nature is not easy, and nature occasionally fools us (you can, rarely, flip an honest coin twenty times and get twenty heads), so if a single observation disagrees with a lot of other information, that single observation will be checked in various ways to see if the new result "stands up" before the older body of knowledge is discarded. Before an idea gains wide currency, that idea is tried in various ways, in many labs, in many places in nature, while models are run and theory is developed. The interlocking of all of these provides the confidence that scientists can use in doing things successfully. Although received wisdom from sacred books can be used for inspiration, scientific ideas must be tested against nature. Social scientists have quite rightly learned that scientists are affected by their prejudices, their funding sources, their mating habits, and other things, and that the path of science is not nearly the straight-ahead road to understanding presented in some textbooks. Unfortunately, some of those social scientists have then gone off the deep end and claimed that science is no more useful than any other human story—claiming that astrology and astronomy are equally valid, for example, or palm-reading and modern medicine. These same social scientists seem to know where to find a real doctor when they get in trouble, however. Science is appealed to nature, and builds on the learning of people from around the world. Airplanes that fly, computers that calculate, small devices that make big explosions, etc. are not socially conditioned ideas but instead are demonstrations of the success of science coupled to engineering.