TPO 27
Section 1
Conversation1-In the Library
Narrator
Listen to part of a conversation at the information desk in the library.
Librarian
Hi. Can I help you?
Student
Where do I go, besides the computers, to look for books on New Zealand?
Librarian
OK. You mean you don’t want to use the computer?
Student
Well, I haven’t had any luck on the computers here.
Librarian
OK. I mean the reason I am asking is you pretty much have to go to the computer to find out where a book is. But I can help you find it on the computer if you like.
Student
That would be great. I just spent half an hour and I couldn’t find anything.
Librarian
I know how you feel. When I first started working here, I couldn’t find anything either. So you are looking for information on New Zealand, is that right?
Student
Yes.
Librarian
Is it like travel information that you are looking for?
Student
Uh… No. Actually what I am looking for is information on a volcano in New Zealand.
Librarian
Oh. OK. Because I know a travel agency that specializes in tours in New Zealand and Australia.
Student
Oh. I’d love to go. I heard it’s beautiful.
Librarian
Yeah.
Student
Maybe someday.
Librarian
Yup. OK. Let’s see … OK. If you want to search the library holdings and don’t know the author’s name or the exact title of the book or an article, you have to set up a keyword search. It is a special function. Then you can just type in some keywords and let the computer do the search.
Student
I see.
Librarian
OK. Oh, how about if we search for volcanoes and New Zealand.
Student
Sounds good.
Librarian
It’s for a geology class?
Student
Mhmm.
Librarian
Ha! You must be from Professor Simpson’s class.
Student
No.
Librarian
Oh. Well, he is a volcano expert, so I thought he might be teaching your class.
Student
No, I’ve heard he is really good though.
Librarian
Yeah. That’s what everyone says. Do you know the name of the volcano?
Student
Mount Ruapehu.
Librarian
Can you spell that?
Student
Sure. It is R-U-A-P-E-H-U.
Librarian
OK. Mount Ruapehu. Let’s see. So are you a geology major?
Student
Hem. Hardly.
Librarian
Let me guess, you have to take a science course and you don’t want to have to deal with biology, chemistry or physics.
Student
Exactly. But it’s actually turned out to be a pretty interesting class.
Librarian
Well, that’s good. Um… does it have to be a book? Or could you use a journal article?
Student
Mhmm… no, either one would be fine.
Librarian
OK. Well, here’s a journal article. Let me check to see if we have it. OK. We have the article, but it is from 2001. Is that OK, you think?
Student
Well, I’d like to have a look at it. The focus is really on eruptions in the last five years, but it might have some useful background material.
Librarian
OK. Well, let’s see what else we can find.
Student
Sounds good.
Lecture1-Marine Biology (Coral Reefs)
Narrator
Listen to part of a lecture in a marine biology class.
Professor
So we have been fairly thorough in our discussion about coral reefs, which of course are prominent, oceanic features made of hard limestone skeletons produced by tiny coral animals. We’ve gone over where coral reefs are usually formed – along the edges of shallow ocean banks in tropical or subtropical regions, and the fact that they are declining at an alarming rate. But I don’t want to leave you with the impression that all is lost. There are several techniques being employed today that could prove useful in assuring the future of the reefs.
Now, we’ve talked in depth about coral bleaching, or whitening, which as you recall, is a symptom of …well that the coral is suffering. As you know, coral is very sensitive to water temperature. Even though one or two degree Celsius rise in sea surface temperature for a relatively short amount of time can cause bleaching. Recently, researchers have used data collected by monitoring surface water temperatures to improve the ability of a reef to recover from bleaching. One future possibility is that improved monitoring can help predict where and when bleaching will occur, which might potentially enable us to mitigate its effects.
And there’s another technique that’s been experimented with to try to help coral reefs recover from bleaching. It’s called coral transplantation. This involves moving young coral from a healthy reef onto a degraded reef, you know, in an attempt to regenerate the degraded reef by encouraging young healthy coral to take over. There has been some success with this, but it’s still somewhat controversial. Some scientists support it because, well for one thing, it means you don’t have to rely on the existing coral to reestablish itself because it might not be able to. But in my opinion, transplanting coral should only be used as … well as a last resort. I mean, this method is not only costly but it’s … well even if it’s successful, it still fails to address the ongoing problem, the root causes of the degradation, which really is paramount to devising an effective solution. So I don’t really take comfort in the successes they have had with transplantation.
Perhaps some more constructive use of our time could be spent at researching corals that do survive, like in areas known as refugia. Refugia are areas on the reef that are seemingly, well resistant to bleaching. See, when coral reefs experience bleaching, it’s rarely a case of the whole reef being affected. There are almost always pockets of coral on the reefs that remain unaffected. And these are often the lower areas of the reef, those located in deeper water, where temperatures are lower.
Now, we have evidence that corals in these locations are able to escape the destructive bleaching that affects portions of the reef in shallower or warmer water. So in my mind, it’s these refugia that are the key components of overall reef resilience. These should be the area of concentration for researchers to locate and protect those regions as a way to sustain coral reefs.
And we can also protect the reefs by protecting the surrounding ecosystems, like mangrove forests and seagrass beds. Both of these grow in coastal waters, often in the vicinity of coral reefs. By protecting these areas, we also protect the coral. Let’s take, for example, the mangrove forests. Mangrove root systems have the ability to absorb and well trap sediments and pollutants in water that flows through them before they enter the ocean. This of course has beneficial results for the nearby coral reefs.
And fishery’s management is another key strategy. Overfishing can be seriously disruptive to coral. Let me give you a couple of examples. Overfishing certain species of fish and shellfish like snappers, barracudas and even lobsters. Well all of these creatures feed on snails, worms and other organisms that eat coral. So depleting the number of lobsters, for example, means that we are adding to the threat of coral decline. Sea urchins are another example. They eat algae and prevent it from overwhelming the coral. Since the disappearance of sea urchins from the waters up the coast of South Florida, many coral reefs there have been smothered by the uncontrolled growth of algae.
Lecture2-History of Musical Instruments (Violins)
Narrator
Listen to part of a lecture in a history of musical instruments class.
Professor
So musical instruments evolved in ways that optimize their acoustical properties, how the instrument vibrates and sends those vibration through the air to our eardrums.
Now professional musicians are very particular about their instruments, they want instruments that help them fully express the intent of the composer, which of course translates into a more enjoyable listening experience for the audience members. Yet most audience members probably aren’t even aware of how much the instrument matters. I mean, OK. Think about the last concert you attended. When you applauded, what went through your mind?
Student
I recently heard a violinist who totally blew me away. So when I applauded, I guess I was showing my appreciation for his skill, the hours of practicing he must have put in.
Professor
And his violin?
Student
Didn’t really think about it. It looked exactly like mine, which is inspiring in a way knowing my violin could also produce beautiful tones, that maybe I would sound that good someday.
Professor
I hope you do. But if your violin isn’t as good as his…
Student
You mean he might not sound as good playing my violin?
Professor
As I said, tone quality differs from instrument to instrument. The question is why. Why does one instrument sound more beautiful than another, even if they look identical?
There’s a particularly interesting case with an extraordinary generation of violins made in Northern Italy, in the city of Cremona, back in the late 1600s - early 1700s. These vintage Cremonese violins are considered the best in the world. But it’s not like the makers of those violins were any more skilled than their modern-day counterparts. They weren’t. Today’s top violin makers can pretty much replicate all the physical attributes of a Cremonese violin. But it’s generally thought that the acoustical quality of modern violins doesn’t live up to the quality of the vintage ones.
Student
So what attributes of the old violins have been replicated?
Professor
Oh, their dimensions, shape, their fingerboard height, uh, general craftsmanship. For a long time, people thought the varnish used to coat and protect the violins was special. But research showed it was the same ordinary varnish used on furniture. However, researchers have discovered that there are something special about the wood the violins were made from. And recently they have been able to replicate that too.
Student
How? Unless the trees that Cremonese used are still alive.
Professor
The trees weren’t replicated, just the wood, specifically the wood’s density. Density is determined by how trees grow. Trees, old trees that don’t grow in the tropics grow seasonally, they grow faster early in the year in the springtime than they do later in the year. So early growth wood is relatively porous. Late growth wood is denser, less porous. And this variation shows up in the trees growth rings. The denser layers are generally darker than the less dense layers. We call this variation the density differential. Variations in wood density affect vibrations, and therefore, sound. When scientists first analyzed the wood of vintage Cremonese violins in compared with the modern violin wood, they calculated the average density and found no difference. Later, other researchers measured the density differential and found a significant difference. Modern violins had a greater variation, a larger differential.
Student
So you mean the density of the wood in the Cremonese violins is, is more uniform?
Professor
Correct.
Student
But Northern Italy isn’t in the tropics.
Professor
No. But climate matters. Turns out the Cremonese violins were made from trees that grew during a Little Ice Age, a period when temperatures across Europe were significantly lower than normal. So the trees grew more evenly throughout the year, making the density differential relatively small.
Student
But you said someone replicated the Cremonese wood.
Professor
The density differential was replicated.
Student
What did they do? Try to simulate an Ice Age climate in their greenhouse and grow some trees in there?
Professor
No, what happened was a material scientist figured out a way to process wood to make it acoustically similar to the Cremonese wood. He basically exposed the wood to a species of fungus, uh, a mushroom. In the forest, fungi are decomposers. They break down dead wood. But this particular fungus nibbles away only at certain layers in the wood, leaving other layers alone. As a result, the density differential of the fungi-treated wood approach that of the Cremonese wood.
Section2
Conversation2-Hydroponics (Chinampas)
Narrator
Listen to part of a conversation between a student and the professor of his history of technology class.
Student
Would it be okay to focus on something related to agriculture?
Professor
Sure, farming technology is fine, as long as it’s pre-modern. But this isn’t a long paper, so are you going to need to pick a specific area of pre-modern agriculture, like irrigation or food crops of ancient Greece.
Student
I am actually interested in hydroponics.
Professor
Hydroponics. Growing plants in water instead of soil.
Student
Well, not in pure water, in water that has the proper mix of nutrients.
Professor
OK. But is it a pre-modern technology? I mean, hydroponics isn’t really my specialty but from the research I have read, we are talking the nineteenth century, maybe the seventeenth century if you really stretch it.
Student
Oh? But the Aztec civilization back in the thirteenth century in basically where Mexico city is today … An article I read said the Aztecs were using hydroponics in something they called … I have got the word right here. Um. Chinampas.
Professor
Chinampas, the so-called floating gardens.
Student
Exactly. So yeah the chinampas, the article said very clearly these floating gardens are proof that the Aztec invented hydroponic farming.
Professor
Well, chinampas are artificial islands built up in shallow lakes. Islands made from packed earth and weeds and uh, material from the bottom of the lake. They may have appeared to be floating in the water, but in fact they reach all the way to the bottom of the lake. So the primary growing medium, what the plants draw nutrients from, is actually soil, not water.
Student
So the article was wrong about that? Too bad, it seems like a great topic, but I guess…
Professor
Wait a minute. Just because chinampas were not technically hydroponic doesn’t mean this couldn’t be an appropriate topic for your paper. Chinampas were still a great technological achievement. I mean, they enabled the Aztecs to grow plenty of food in an area without much available farmland.
Student
But I wondered why the author wrote that chinampas were hydroponic.
Professor
Well it’s pretty common for writers to generalize, say use a term like hydroponics to describe other types of agriculture. Personally, I would never say hydroponic except for plants growing in liquid. The crops on chinampas definitely benefited from the water surrounding them. But… hydroponic…
Student
OK. So I will go with chinampas but leave out with the hydroponics part.
Professor
Actually, there’s an important lesson here. We should pay attention to what happened in history but also how historical events are presented. Why, for example, would writers use a word like hydroponics so casually?
Student
I guess ‘cause it’s a popular topic people want to read about?
Professor
Or to help modern-day readers to understand something historical, maybe these writers think a familiar frame of reference is needed.
Student
Well that article was in a popular magazine, not a scholarly journal for historians.
Professor
OK. But historians sometimes do the same thing.
Student
So I guess then that all historians might not describe chinampas in quite the same way either.
Professor
Good point. Why not look into that too? And include it along with your description and analysis.
Lecture3-Zoology (Sauropods)
Narrator
Listen to part of a lecture in a zoology class.
Professor
Your reading for today touched on dinosaur fossils from the Mesozoic era, which ended about 65 million years ago. Today we will be discussing the sauropods. I think our discussion of sauropods will illustrate what we can learn by comparing the fossil record to modern animals. By fossils, we mean traces of prehistoric animals such as bones, which become mineralized, or impressions of bones or organs that are left in stone.
Now sauropods were among the largest animals to exist ever! They were larger than blue whales, which are the largest animals alive today. They weigh up to one hundred tons, twenty times as much as elephants. Also, they were an extremely successful kind of dinosaur. There’s evidence of sauropods in the fossil record for an unusually long time, over one hundred million years.
So, why were sauropods so successful?
Biologically speaking, sauropods shouldn’t have been successful. Large animals like elephants, say, they require much more food and energy and have fewer offspring than smaller animals. This makes maintaining a population harder. The largest animals today don’t live on land. But in the ocean where food is easier to find, a blue whale, for instance, can eat up to 8,000 pounds of food a day. And they give birth only once every few years. We also know that body heat, that… well, large animals can’t easily get rid of excess body heat. But for an oceangoing whale, that’s not a problem. For a 100-ton land animal, it can be.
For years, we have assumed it was the abundant plant life of the Mesozoic that allowed these giants to thrive. However, we now know that since oxygen levels were much lower in the Mesozoic than we assumed, there was much less plant life for sauropods to eat than we thought.
So now, well, we are looking at other… we are, we are trying to understand the biology of sauropods, comparing their fossils to the anatomy of modern animals to get a better idea of how they lived. What we’ve found is that sauropods were experts at conserving energy. They had enormous stomach capacity, the ability to digest food over a long period, converting it to energy at a slower pace, saving it for later. For animals with small stomachs, it takes lots of energy to constantly look for food and then digest it. With larger stomachs and slower digestion, you don’t need as much energy. Joseph?
Student
Does… do scientists actually know about sauropods from looking at… I mean, how much can we actually learn looking at some ancient bones compared to all we can learn from modern animals? And, comparisons between animals that lived millions of years apart? well, it just seems… more like guessing.
Professor
There’s always some guesswork when studying extinct animals. But that’s exactly what leads to discoveries, a hypothesis, a type of guess is made. We guess the hypothesis by looking for evidence to support it. Then some questions are answered, which may lead to new questions. For example, let’s look at one of these comparisons.
We know sauropods couldn’t chew food. Their skulls show they had no chewing muscles. Lots of modern animals, like birds and reptiles, also can’t chew food. They need to swallow it whole. But modern animals have an interesting aid for digesting food. They swallow stones, stones that are used to help grind up the food before it’s actually digested in the stomach. These stones are called gastroliths. Gastroliths make food easier to digest, essentially smashing food up, just as we do when we chew. Over time, gastroliths inside the animal are ground down and become smooth and rounded.
Now, sauropod fossils are commonly found with smooth stones. For years we thought these were gastroliths. They look just like gastroliths and were found in the area of the sauropods’ stomachs. A recent study measured the gastroliths in modern animals, in ostriches. And the study showed that ostriches need to ingest about one percent of their total body weight in gastroliths. But we have been able to determine that the stones found with sauropods totaled much less proportionally, less than a tenth of one percent of their body weight.
So now we are not quite sure what these sauropods’ stones were used for. It could be they were accidently ingested as the sauropods foraged for food, that they served no real purpose. Other researchers speculate that sauropods ingested these stones as a source of some the minerals they needed, such as calcium.
So the original hypothesis that the stones found with sauropods were gastroliths, even though it hasn’t been supported, has helped us to make new hypotheses, which may eventually lead to the answer.
Lecture4-Studio Art (Primary Colors)
Narrator
Listen to part of a lecture in a studio art class.
Professor
OK. As you probably know, primary colors are, theoretically speaking, the basic colors from which all other colors can be made. But as you’ll find out when you start working on your painting projects, the three primary colors – red, blue, yellow – don’t always make the best secondary colors. Combining red and blue, you will probably never get a fantastic violet. To get a nice violet, you’ll have to add white. Combining yellow and blue, you will almost never get a satisfactory green. You are better off using a pure green pigment.
The idea of primary colors, and specifically the idea of red, yellow and blue being THE primary colors, didn’t exist until about 200 years ago. Until then, the dominant theory about color was one that had been proposed by Isaac Newton. Newton gave a scientific and objective explanation of colors. He used a prism to break white light down into the various colors of the spectrum. And he theorized, rightly so, that different colors are essentially different wavelengths of light. But he made no mention of primary colors. That idea came from, or was at least published by a man named Johann Wolfgang von Goethe.
Goethe was a well-known author. He wrote many famous novels, plays, poems. So why did he start thinking about colors?
Well Goethe was part of the Romantic Movement in western literature. And he was a Romantic, through and through, meaning that he explained objects and phenomena in terms of the spiritual, emotional impact they had, as opposed to explaining them in terms of their scientific nature. He rejected an objective understanding of color, in favor of a more subjective understanding. He believed that when we see color, it stimulates our emotions. And different colors appeal to or inspire different emotions in different people.
Student
That sounds like psychology.
Professor
Well, color theory is used in psychology too. Some psychologists do use their field’s version of color theory to diagnose and treat patients. Um… anyway, Goethe conducted a number of experiments trying to figure out which colors corresponded to which emotions. And in terms of that goal, he wasn’t very successful. But his experiments actually did show a lot about the relationships between colors themselves, about how colors change when placed next to other colors, about how they interact with one another. Scientists studying optics and chromatics today still marvel at his findings. But Goethe wasn’t really able to establish a clear connection between colors and emotions.
Then in 1806, he received a letter from a relatively unknown German artist, a painter named Philipp Otto Runge. In the letter, Runge outlined his own color theory, specifically the connections he made between colors and emotions. And his ideas about what colors symbolize, about the emotions that different colors inspire were based on the colors red, yellow and blue. Runge’s choice of red, yellow and blue had nothing to do with what we know from modern-day chromatics, it had to do with Runge’s complex system of symbolism, his experience of nature, particularly with his experience of the quality of light at various times of the day, morning, noon and night. So each color had a specific symbolic value.
Well, four years later, Goethe published a book entitled Color Lesson. In Color Lesson, Goethe COINCIDENTLY cites the same colors as primary colors. At this point, Goethe was already a well-known author, so he was easily able to popularize this idea of primary colors, and specifically the idea of red, yellow and blue as THE primary colors.
Student
But he didn’t mention Runge?
Professor
Well, he did put Runge’s letter in the book, at the end. But he added a disclaimer implying that Runge’s letter didn’t influence his work. Apparently, what Goethe was saying was that they just HAPPENED TO come up with the same theory at the same time.