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The Need for Conceptual Approaches to Understanding Change through TimeNUHFER, Edward, Geosciences and Center for Teaching and LearningIdaho State University, Campus Box 8010, Pocatello, ID 83201, nuhfed@isu.edu

“I was an engineer--a canal builder. I was the first to know that fossils found within a bed of rock can be traced. Even after the layer has disappeared locally, it may be rediscovered at some distant outcrop and the fossils within it matched to the original site. My work was even recently honored in a bestseller book in 2001, The Map That Changed the World…” 2 - A William Smith

We can understand the relative ages of rock. The oldest layers were lain down first, and are thus at the bottom of a sequence. 1 - J Nicolaus Steno

I was a contemporary of the canal builder and was first to consider: “Why are some fossils restricted only to certain layers, and most of them lack any living counterpart?” I proposed that there have been catastrophic extinctions. 3 - I Baron Georges Cuvier.

I deduced relative dating principles of cross-cutting relationships. My name is most often associated with the phrase “The present is the key to the past.” By this, I meant that we could understand and explain about all we could find in the rock record if we understood what was happening on the Earth’s surface today. For that I’m sometimes called “The Father of Modern Geology.” 4 - K James Hutton

The earth is governed by processes that "never acted with different degrees of energy from that which they now exert." "All theories are rejected which involve the assumption of violence and catastrophes and revolutions of the whole earth and its inhabitants...theories which are restrained by no reference to existing analogies..." I wrote the first geology text… 5 - B Charles Lyell.

I was a famous physicist. My laws that I discovered about the rate of cooling of objects and the equations that describe these are still in use in your time. I calculated the age of the Earth to be about 100 million years old based on my calculations of radiative cooling. I figured that if Earth were red hot, just like a heated cannonball when it was formed, it would cool in accord with the same equations that could describe the iron cannonball. That always came out to be about 100 million years old. PHEW! The geologists hated that! 7 - D William Thomson (Lord Kelvin)

I did my work around the time of the physicist. I calculated the age of the earth to be about 80 - 90 million years old based on ocean salinity. I assumed the first oceans came from rainwater and were fresh, and that streams ran in with mobile ions like Na+ and so forth, so all I had to do was to calculate how long it would take the oceans to come to their present salinity based on contributions of dissolved substances from all the world’s rivers. I was quite pleased to see my age turn out about the same as the physicist’s. 8 - H John Joly.

I was largely self-taught and grew up in the Midwest. I eventually graduated from a small college there, and I became one of the world’s most influential geologists and educators. I was devoted to teaching others how to teach themselves. I deduced a major method of science—the method of “multiple working hypotheses." I certainly am one person the physicist referred to--I hated his 100 million year old age limit for Earth. 9 - L Thomas Chamberlin

The word you now use: “radioactivity?” It came from me. I discovered radium and was the first person ever to be awarded two Nobel prizes--one in physics and one in chemistry! I shared one award jointly with my dear husband and colleague, Pierre. I also discovered the nature of radioactive decay. While I really wasn’t concerned much with the arguments of geologists, my discovery surely knocked the props out from under that age of Earth derived from the heated cannonball. 10 - F Marie Curie.

I was a great fan of the dual recipient of the Nobel Prize. I deduced that if lead was the final product of the radioactive decay of uranium and thorium, I could measure the rate at which uranium breaks down (its half-life), I might use the proportion of lead in uranium ores as a kind of clock. The first ore I dated put Earth's age at 2.2 billion years. This was a dramatic increase in the estimate of Earth's age --- so dramatic that it shocked physicists and geologists alike. 11 - E Bertram Boltwood

I passed from this life in 2002. Most of you have probably read at least one of my books or essays. I delighted in writing books for non-scientists, and I had a particular gift for it. I worked with a colleague at the Museum of Natural History on organisms’ change through time, and we saw a rather jagged pattern of change punctuated by stops and then great changes. A large number of natural changes occur as punctuated events. 12 - G Stephen Jay Gould

General Education Goal Outcome: It is important to understand where ideas and concepts came from and how we obtained them. Pick a concept from this core science course, and explain its historical development.

Goal met by learning development of the concept of “Deep Time.” Teaching Method : A Mystery Séance

ABSTRACT. Science involves study of the physical world: matter, energy, and time. A primary contribution to science by geologists involves the understanding of change through time. Yet, introductory textbooks and traditional instruction impart factual knowledge (age of Earth and presentation of the Geologic Time Scale) rather than promote conceptual understanding. Introductory students arrive with limited, self-made common-sense interpretations about change through time, and most are dead wrong. Ability of students to comprehend the planet, their environment, and their place and role in these in ways that are useful to their own lives requires more than recognizing that Earth is old; it requires students to develop sophisticated, conceptualized thinking about time. The study of the discovery of deep time is a marvelous topic to allow students to comprehend science as a way of understanding the physical world through two major methods: repeated experimentation and historical/multiple working hypotheses. Texts and instructors should work to convey deeper conceptual understanding of change through time—not as merely age and ordered events— but also as patterns, rates, magnitudes, durations and frequencies. Questions of great importance include the following. (1) How do we understand change through time? (2) What are the patterns, rates, magnitudes, durations and frequencies of a given process? (3) What variations are reasonably expected? (4) How do the changes we see now compare to those we deduce from the past? (5) How do changes caused by human activity compare with natural changes that would occur without such activity, and what are the consequences of such change? This poster will show methods and exercises for promoting such conceptual learning.

Patterns in Time

Learning to perceive change through time.

A Grave Problem

1. Visit any graveyard in the area: select three different headstones, and include in your selection a span of dates that go back 70 or more years. Identify the rock type; look closely at the stone, and relate what you notice to the weathering (Chapter 6) of your text. You can do this in pairs or groups, but the ground rule is that everyone makes the visit and everyone contributes to the observations. Some cultures find it bad taste to visit graveyards. If yours falls into that category, use dated cornerstones of buildings in the downtown area instead to accomplish the same. There are plenty of old structures in Pocatello. After having actually seen weathering of rock yourselves, decide which statement below best fits your observed evidence.

(A) In general, the land wears away at the rate of about 1mm/yr.(B) In general, the land wears away at the rate of about 1mm/decade.(C) In general, the land wears away at the rate of about 1mm/century(D) In general, the land wears away at the rate of about 1mm/1000 yrs.

Are the above hypotheses? If so, what method(s) of science are you employing?

2. Go to the web and use Alta Vista Search engine. Look up “erosion rates” and see if a reference substantiates your rate observation. Bring report—one or two sentences back to class.

3. (Done a week later) Gather into groups of four and share graveyard observations and come up with best rate estimate. Briefly, describe what you found to your three other members in the group. What evidence of weathering did you discover?4. (Following Class Period) Use your best estimate of rates derived from your work above to answer two questions: (A) Pocatello is about 4400 ft above seal level. Use your rate to calculate how long it would take to erode this area to sea level. (B) Let’s consider a magnificent gravestone marker about ten feet high. Use your rate to calculate about how many years it will take to remove it. 5. (Next Following Class Period) To answer “A” and “B” above consider that the Earth is 4.6 billion years old. What percent of geologic time is spent in removing Pocatello and the gravestone? Next, frame 4.6 billion years in terms of a 24-hour day. In that context, how much of that 24-hour day would be consumed during removal of Pocatello and the gravestone?

Can experiential learning extend limits?Laymen who evaluate their lives over years spent in their geological environment often report perceptions of comforting stability and permanence. The landscape seems familiar; hills, valleys, and features on maps appear changeless. Of course, the perceived permanence is illusion. It arises because one lifetime of experiences is small beyond imagination, relative to deep time, and we are not naturally attuned to looking to see the tiny subtle variations that might be the key to envisioning our reality. This exercise sends students to gather some simple data and challenges them to evaluate field observations in discussions with others against multiple hypotheses. Finally, it leads them to derive their own awareness of deep time but based on what they see, not on what they are told.

Our perception of patterns in time often dictates how we interpret phenomena. Perhaps no other aspect of time suffers more from misperceptions than that of patterns. The horizontal line (A) shows time’s passage without change. Laymen who evaluate their observations over years spent in their geological environment often report perceptions of comforting stability and permanence described by this line.

The inclined line with positive slope (B) shows change at a gradual, constant rate. The graph of gradual change expresses the perception of change taught by Charles Lyell as the manner through which natural processes act. Statements such as the Earth is governed by processes that "never acted with different degrees of energy from that which they now exert" (Lyell, 1829) and "... All theories are rejected which involve the assumption of violent catastrophes and revolutions of the whole earth and its inhabitants...theories which are restrained by no reference to existing analogies..." (Lyell, 1842) reveal Lyell’s devotion to gradualism. Despite the fact that few “existing analogies” in geology really operate in ways that fit Lyell’s gradualism, geologists interpreted phenomena in accord with his views for over a century. Specialized departments and “majors” were not prevalent in Lyell’s time, so all who attended university were likely to have read his Principles of Geology. The consequential reach of his dogmatism even into modern thinking in many areas outside science is rarely appreciated.

The pattern in C (seasonal temperatures in Minnesota) depicts a cyclic pattern that occurs at regular repeating intervals, an example of Gould’s “…Time’s Cycle.” It achieves perfect symmetry and regularity in the—the graph of the sine function in mathematics. Cyclic patterns describe significant natural phenomena and have character of predictability.

Pattern (D) appears random, but this graph, a rainfall record from Minnesota, is fractal! In words, a fractal pattern in time manifests as many common events, a few intervals when events are absent or abnormally small, infrequent large events, and very rare catastrophic events that would never be anticipated by direct observation of the usual events (unless one understands already that the pattern is part of a fractal system). Fractal patterns in time appear “random” but their fractal character manifest when clearly linear relationships appear from plotting recurrence interval of events of a given magnitude versus the size of the magnitude of the event (see left). Hurst (1951) deduced such patterns when he studied the longest temporal data record for any natural phenomena —the record of floods on the Nile River. The amazing inherent order described by Hurst led to the discovery by Benoit Mandelbrot of fractals as a fundamental descriptor for patterns of natural events. The order present in such a line allows estimate of the size of larger events, such as a 100-year flood, even though no witness has yet recorded the event. While, fractal patterns in time can describe magnitudes and frequency they don’t have the quality of predictability that allows one to say when a specific event will occur.

Patterns of exponential decay or growth fit only a limited number of natural phenomena over deep time. Decay of radioactive parent and growth of daughter products fit this. Exponential patterns largely describe how humans operate. Consider our economic system, savings accounts, retirements, etc. that depend upon exponential growth. Our population growth that strains global resources is an unprecedented event in Earth history.

The awareness of patterns can be developed by getting students to match various processes with the patterns under which they operate. Consider the following: rainfall,tides, flooding, landslides, sunspots, diurnal cycles, tsunamis, earthquakes, change in speed of Earth’s rotation, mass of Earth. What patterns describe each through deep time. In-class drills with discussion that use “Visible Quiz” in conjunction with PowerPoint are an easy way to produce an interactive PowerPoint presentation and develop discussion.

Cutting of the Grand CanyonThe pattern that best describes the event above is

A - Constant

B - Rhythmic (cyclic)

C - Fractal

D - Exponential

Volume of ocean water past 500 million yearsThe pattern that best describes the event above is

A - Constant

B - Rhythmic (cyclic)

C - Fractal

D - Exponential

Structured Group Work

A fifteen minute lecture on varve-forming processes precedes the group work.

Next, students in groups of four have the diagram to left from Elk Lake, Minnesota. Groups draw cards that have the following roles:

Age Group Duration Group Frequency Group Ordering of Events Group Pattern Group Rate Group

Groups spend ten minutes to focus on that quality and then report out in order to build an interpretation of the Elk Lake profile and its meaning.

PICK A ROLE - WHAT DO YOU SEE?

Take-home Assignment.

Pick a geological process and explain its temporalbehavior. Consider age, pattern, rate, frequency,duration and range of magnitudes. (Product was a tableproduced by the entire class.)

Topics Chosen by Students

avalanche (snow)coal mine subsidencecoastal erosioncondensationcoral growthcreepdeforestationdissolution of calcitedroughtdune movementEarth's rotationEl Niñoevaporation (Corpus Christi,TX, USA)Evaporite accumulation -Castile Anhydriteexfoliationfault movement (San Andreas)forest firesglacial movementglacial ablationhillside slidehurricanesmagma crystallizationdeltaic sedimententationoceanic (abyssal)sedimentation

photosynthesis --O2production (corn leaves usedas example)plant growth cyclesplate tectonicsplate tectonics (folding)rainfall precipitationRocky Mountain buildingsea floor spreadingsea level changesedimentation in a man-madereservoirsedimentation in a lakesolifluctionsortingstalactite growthstromatolite growthsunspotstectonic upliftingtidal cyclestornadotree ring growthvolcanismwinds at Earth's surface

Jigsaw Activity

Create a rate table as a class project. Each student picks a unique topic that cannot be duplicated. Results are emailed to instructor who distributes the class product as a reference.

I was influenced greatly by the lawyer. I upset many folks with what I discovered. In fact, I probably upset more people than anyone on your list! Who could have guessed that studying a bunch of *!#!! finches would have caused such a ruckus?! I believed that among fossils were animals that could be our ancestors and that the rock record would reveal this… 6 - C Charles Darwin.

A Dozen Spirits: A Séance on Change through Time!

The following lists people whose contributions are essential to our understanding of geologic time.Suppose we held a séance and the spirit of each could speak to our class. Each person could tellsomething about him/her self that would help us to capture the history of the development of ourthinking. However, these spirits do not have the good taste to appear in order in which they lived!It's up to us to sort out what they tell into a correct order—to order the events in time. The table isin the correct order, but the order in which the sprits actually appear is not the order of the table,but rather is in the order of letters with their words below the table. Your first task is to use yourown wits to match the letter of the quote with the individual who would most likely provide suchinformation. Write your first tries in column A. Tomorrow, we'll work briefly in groups of four tosee if you can improve compilation of matching statements (letters) with persons. After this, we'llwork together to complete the table as a group in column C.

A. “ I was an engineer--a canal builder. I was the first to know that fossils found within a bed of rock canbe traced. Even after the layer has disappeared locally, it may be rediscovered at some distant outcropand the fossils within it matched to the original site. My work was even recently honored in a bestsellerbook in 2001 -- The Map That Changed the World…”

B. The earth is governed by processes that "never acted with different degrees of energy from that whichthey now exert." "All theories are rejected which involve the assumption of violence and catastrophesand revolutions of the whole earth and its inhabitants...theories which are restrained by no reference toexisting analogies..." I wrote the fi rst geology text, and my thinking aff ected the way every geologistsaw Earth events up until about the 1970s. I was also a lawyer, and so I tended to argue well and bequite nasty. I used my influence to detract from those who disagreed with my views.

C. I was influenced greatly by the lawyer. I upset many folks with what I discovered. In fact, I probablyupset more people than anyone on your list! Who could have guessed that studying a bunch of *! #!!finches would have caused such a ruckus?! I believed that among fossils were animals that could beour ancestors and that the rock record would reveal this. I was concerned however, that we did not fi ndmuch in the gradual changes of one form to another in fossils. I attributed this to the fact that we justhad not studied enough rock to yet have a detailed record that would reveal all the missing links.

Person A-myfirst try

B- OurGroup try

C-correctmatch

1. Nicolaus Steno (Neils Stensen) (1669)2. Wil liam Smith (1769-1839),3. Baron Georges Cuvier (1769-1832)4. James Hutton (work of 1795)5. Charles Lyell (1797 - 1875),6. Charles Darwin (work of 1859),7. Wil liam Thomson (Lord Kelvin - work in

1897),8. John Joly (work of 1908),9. Thomas Chamberlin (work of 1899 - 1909),10. Madame Curie (1867 - 1934),11. Bertram B. Boltwood (work 1905 - 1909) ,12. Stephen Jay Gould (work 1972 –2000)

D. I was a famous physicist. My laws that I discovered about the rate of cooling of objects and theequations that describe these are still in use in your time. I calculated the age of the Earth to be about100 million years old based on my calculations of radiative cooling. I figured that if Earth were redhot, just like a heated cannonball when it was formed, it would cool in accord with the same equationsthat could describe the iron cannonball. That always came out to be about 100 million years old.PHEW! The geologists hated that! Whenever they objected to my age estimate, I told them to gohome and learn some arithmetic, and when they could make a mathematical argument as good as mine,then we’d talk. They REALLY hated that!

E. I was a great fan of the dual recipient of the Nobel Prize. I studied the work of others and foundthat lead was always present in uranium and thorium ores. I deduced that if lead was the final productof the radioactive decay of uranium and thorium, I c ould measure the rate at which uranium breaksdown (its half-life), I might use the proportion of lead in uranium ores as a k ind of clock. This ofcourse was based on quite rigorous mathematics, and there was no question this time about “status.”We had numbers with real snob appeal! The first ore I dated put Earth's age at 2.2 billion years. Thiswas a dr amatic increase in the estimate of Earth's age --- so dramatic that it shocked physicists andgeologists alike. Probably the geologist from the Midwest would have been taken aback, even as muchas he would have loved to live to see the day!

F. I was both a scientist and a romantic! I liked to dance and ice skate and had my heart brokenwhen my first love would not marry me because of my lesser economic class. I w ent on to becomeeducated and eventually found both love and success. The word you now use: “radioactivity?” It camefrom me. I discovered radium and was the first person ever to be awarded two Nobel prizes--one inphysics and one in chemistry! I shared one award jointly with my dear husband and colleague, Pierre. Ialso discovered the nature of radioactive decay. While I really wasn’t concerned much with thearguments of geologists, my discovery surely knocked the props out from under that age of Earthderived from the heated cannonball. Pierre and I s howed that radioactive decay released heat. Ifradioactive material heats the Earth within, it surely would do nasty things to any models that assumeda regular rate of cooling!

G. I passed recently from this life in 2002. Most of you have probably read at least one of my booksor essays or had seen me on television. I loved teaching; I delighted in writing books for non-scientists,and I had a particular gift for it. I worked with a colleague at the Museum of Natural History on thatissue of change through time, and together we concluded that the influential lawyer should have paidmore attention to what he was seeing and less on being argumentative. We could not agree with thelawyer’s view that change through time was gradual. In fact, if one really looks at how things change,nothing much works that way in geology. Instead, we saw a rather jagged pattern of change punctuatedby stops and then great changes. It affects organisms, and it affects a large number of natural changes.Many things occur as punctuated events. The lawyer in fact did do exactly what he claimed—heinfluenced what geologists saw for over a c entury! The inability to perceive the obvious simplybecause one has been told to see something else is a profound lesson to all future scientists.

H. I did my work around the time of the physicist. I calculated the age of the earth to be about 80 - 90million years old based on ocean salinity. I assumed the first oceans came from rainwater and werefresh, and that streams ran in with mobile ions like Na+ and so forth, so all I had to do was to calculatehow long it would take the oceans to come to their present salinity based on contributions of dissolvedsubstances from all the world’s rivers. I was quite pleased to see my age turn out about the same as thephysicist’s. It gave me confidence. In fact, so much confidence that I never could accept the value ofthe later methods that disproved my age estimates.

I. I was a contemporary of the canal builder and was first to consider: “Why are some fossilsrestricted only to certain layers, and most of them lack any living counterpart?” I proposed that therehave been catastrophic extinctions. "Why has not anyone seen that fossils alone gave birth to a theoryabout the formation of the earth, that without them, no one would have ever dreamed that there weresuccessive epochs in the formation of the globe." I was darned unpopular with some others because ofthis statement.

Solve the Séance mystery! Try your hand at the exercise on the three page handout. The answer key follows.

Concept - Relation of human existence to deep time. Teaching method- storytelling

Highlights of Ma Earth's Housewarming Party©Edward Nuhfer

Once upon a time, Mother Earth decided to have a housewarming party. She returned from the store at midnight with all the goodies required and began to mix the dough and prepare refreshments. By 1:02 in the morning, all the dough had been made into cookies. However, the oven overheated and left the whole house rather smoky and with a disagreeable odor. Even the swimming pool smelled bad. The bacteria and cyanobacteria (those nicknamed blue-green algae) were early risers and were among the first guests to arrive at about 5:00 A.M. They were very helpful creatures and worked all through the day on ventilation of the pool and later on the household air. By about 6:30 P.M. in the evening, they had the house fresh-smelling, in time for when the first animals began to arrive. By 9:00 P.M., the party was really hopping! All kinds of strange and wonderful creatures greeted the fish and shell fish at the door, and many guests came and went. The Coral family arrived at 9:15. Shortly before 10:00 P.M., the amphibians joined the party at the edge of the pool, and they brought with them potted plants and even trees as housewarming gifts. The guests grew numerous, and there were so many plants that soon the area around the pool was converted into a garden. Many guests of the party had moved from pool to the garden by just after ten o'clock. However, all those plants had attracted a number of flying insects, so that by 10:15 P.M. it became very difficult to carry on conversation there. The reptiles arrived at about 10:20 P.M., but they enjoyed the garden—they were neither bothered much by insects nor were they enthusiastic conversationalists.

Then a large group of boisterous dinosaurs came in the door at about a quarter-to-eleven. They swaggered, stomped and ran about, and frightened many of the guests, including the birds and small mammals who had arrived just a few minutes before 11:00. Most of the guests kept their distance from the dinosaurs, but the dinosaurs had such a wild time that they were soon exhausted. The fireworks caused the larger ones and most of the other guests to leave the party abruptly at 11:38 P.M— never to return. The garden had gotten muddy from all the stompings and carryings on, so when some newly arrived large mammals and a troupe of new guests saw the state of things, they decided the garden would look better with some sod. They worked quickly and in less than ten minutes had the garden quite beautiful with lush grass. Ma Earth's house was back in very good shape by a quarter to midnight.

Eight minutes before midnight, the doorbell rang and Ma greeted some hominids at the door. Unlike the reptiles, the hominids were very vocal and all enjoyed polite chit-chat for a few minutes until 30 seconds before midnight when the first humans finally arrived.

The early arrivals were polite and fit in well at the party, but problems started when the later human creatures presumed that the party was just for them. They were surprised to learn that so many guests had come and gone already. "Are we really so very late?" they asked incredulously. They were not too well mannered to the other creatures either. They began to tear up the trees and grasses and quarrel with one another. They even smoked and insulted the algae and soon the house quickly began to smell stale. Ma Earth warned them that unless they learned better manners, they would have to leave.

All fell silent at the stroke of midnight, as all the guests watched to see what the humans would do.