CD 2-1
    Narrator: Listen to a talk in a statistics class.    Professor (male): I'd like to explain how the grading system for the course works. By the way the system is the one adopted by all the departments in the college. Its premise is that grades are a system of communication and, therefore, are worthless unless everyone uses them the same way. We issue transcripts so that employers and graduate schools will how well you, students, have performed.     Here's how people across the country will interpret the grades we give: A: The student did as well as could be expected.B: The student did as well as could be expected with some flaws.C: The student met the minimum requirements for the course.D: The student learned some of the material but did not meet minimum requirements.F: The student learned little or none of the material, that is, he failed.    There's no point in saying that the letters "ought" to mean something else -- for instnace, that C "ought" to mean "average." When you speak a language, you have to use it the way people use it. or they won't understand you.    Female student: So, your grading system is universal and follows the standard of the country?    Professor: Exactly. Uh, also grades measure results, not effort. You're not on Sesame Street any more, folks! It may sound charitable to "grade on effort," rewarding hard work with higher grades even in the absence of measurable results. This, however, won't work in practice. I have no way to measure how hard each of you work, do I? Mind you, despite recurring rumors, I'm not a god. Anyhow... Yes?Male student: Um, well, may I say something?    Professor: Okay, shoot!    Male student: You mean effort doesn't count at all? It seems to me kind of, um, unfair not taking into account differences in things like natural aptitude and learning styles.Professor: Sorry, but the university gives degrees for mastering course material, not for enduring drudgery, and grades are part of a degree. No matter how much you sweat in the process, it doesn't count unless you cross the finish line. Would you rather be operated on by a doctor who had an easy time in medical school, or by one who had a hard time and got his passing grade "on effort"? Grading on effort can conceal incompetence or, at best, send you into advanced courses for which you aren't prepared.    Male student: When you put it that way, yeah, it makes sense.    Professor: All right, then. Now that we are on the same page, there is one thing I'd like to mention. That is, grades are not numbers. We use numbers to make certain that grades given fairly, but the grade itself is a teacher's professional judgement of a student's mastery of the subject. It does no good to tell the world that you scored between 80 and 90 on my exam, unless I also tell the world exactly what is on the exam. Likewise, it makes little sense to issue arbitrary course descriptions that "B is 80 to 90." The University publishes course descriptions, not exams.    Male student: But you'll give us the range of A's, B's and C's. Like top ten percent gets A's and bottom ten percent gets F's, or some like that. I think it is very precise and fair way of grading.    Professor: Are you sure?    Male student: Well, that's our high school teacher always told us. The fairest method of giving grades. And he gave us the range of scores for each letter, you know. Was he wrong? Professor: Oh, yeah, of course, I'll give you grade ranges. But not percentage. You're talking about two different things. There's no percentage in giving grades according to certain set raitos, as they say. You know why? Because students should be graded against course requirements, not against other students. Don't get me wrong, I'm sure a certain amount of competition among you guys is very healthy, but you shouldn't suffer because your fellow students do well, nor benefit because they do badly. Do you know where I'm coming from? A graduate school or employer will want to know whether your fellow students failed to do so. And so, to answer your question, yes, your high school teacher was wrong. Do you see that now?    Male student: Completely.    Professor: All right. Uh, this method of giving grades based on how a student's work compares with other students' is called "grading on a curve." You may have heard of it because a lot of IQ tests and other standardized tests use that. But what most non-statisticians don't realize is that "grading on a curve" works well only when the class is enormous -- with perhaps 1,000 students -- and, uh... only when the student performance is known to be constant over time. Alas, we are just mortals and our performance can fluctuate from year to year, or from day to day for that matter. So, in a class of around 50, like ours, random variation will surely invalidate any attempt to give A's, B's, and C's to fixed percentages of the class. Believe me -- I make a living being a statistician. And on top of that, grading on a curve allows students to sink to any depth as long as all students sink together. A scary thought, isn't it?     Oh, by the way, I refer all cases of suspected cheating to the Office of Judicial Programs. This may sound a bit heavy-handed, but it's the only way to make sure that the student gets a confidential investigation by experts followed by a fair hearing. Of course, if it's proven that he was indeed dishonest, he gets the F that he earned.    Female professor: Fair enough.    Professor: I wouldn't dream of being anything other than that!
CD 2-17
    Narrator: Listen to a part of a lecture in an astronomy class.    Professor (male): Good afternoon, everybody. Today I'm gonna talk about our solar system and the Milky Way. Well, first, about the Solar System. As you well know it, it consists of a central star, the Sun, and the bodies that orbit it. Well, let me ask you guys: what are these bodies?    Male student: Things orbiting the Sun include planets and their moons and asteroids and some comets, too.    Professor: Yeah, if you add meteroids, the list of these bodies will be complete. This list used to include nine planets and their 61 moons, asteroids, comets, and meteroids. But jsut a month ago, on August 24, the International Astronomical Union passed a new definition of planet tha puts Pluto in a new category of "dwarf planet." So now we have 8 genuine planets and Pluto. Besides all of these, the Solar System contains interplantary gas and dust as well.    The planets in our solar system differ greatly from each other. For example, Mercury, the closest to the Sun, has a surface temperature of 400 degree Celsius, while on Neptune, on which winds blow up to 2,000 kilometers, or 1,200 miles, an hour -- uh, on Neptune, the mean cloud temperature reaches a low of minus 193 to 153 degrees Celsius. Pluto, now called "dwarf," which is 3.6 billion away from the Sun -- that is 40 times the distance between Earth and the Sun -- the temperature reaches a low of minus 230 degrees Celsius. Also, all of the planets, only five are visible to the unaided eye; to see Uranus, Neptune, and Pluto -- the farthest three -- a telescope is needed. The same is true for the rings of Saturn and for the asteroids, or "minor planets," that orbit around the Sun, especially between Mars and Jupiter, by the thousands.     The planets fall into two groups: four rocky, uh, four small rocky planets near the Sun -- Mercury, Venus, Earth, and Mars -- and four planets farther out, the so-called gas giants -- Jupiter, Saturn, Uranus, and Neptune. Between the rocky planets and gas giants is the asteroids belt, which contains thousands of chunks of rock orbiting the Sun. And Pluto -- it's very small, solid, and icy and its status had been faltering, so to speak. Um, what I mean is ... er, well, you many have read in the newspaper or some science magazines that Pluto's small size, icy composition, and tilted, elliptical orbit have led some astronomers to debate its classification as a planet... Some always throught it was sort of, uh, out of it. Those scientists believed Pluto should be grouped with the asteroids or comets, er, because... The reason is because several other icy bodies have recently been found beyond the orbit of Neptune. Anyway, Pluto is the outermost planet of sort, except when it passes briefly inside Neptune's orbit.    Most of the bodies in the Solar System move around the Sun in elliptical orbits located in a thin disk around the Sun's equator. All the planets orbit the Sun in the same direction -- uh, counterclockwise when viewed from above -- and all but Venus, Uranus, and Pluto also spin around their axis in this direction. Moons also spin as they, in turn, orbit their planets. This entire Solar System orbits the center of our galaxy, the Milky Way, which is today's second topic.    The Milky Way is the name given to the faint band of light that stretches across the night sky. This light comes from stars and nubulae -- clouds of dust and gas -- in our galaxy, known either as the Milky Way Galaxy or simply as "the Galaxy." By the way, does anyone know how many stars there are in the Galaxy?    Female student: A lot. Like several billion?    Professor: You're right hat there're a lot. And nobody knows exactly how many, but the number of stars has been estimated be between 200,000,000,000 and 400,000,000,000. The Galaxy is shaped like a spiral, with a dense central "bulge" that is enriched by four "arms" spiraling outward and surrounded by a less dense "halo."    The Milky Way is actually the plane of the disk of our galaxy. Our Sun is one rahter, um faint, example of these zillions of stars that make up our galaxy. The Sun is in this disk about two-thirds of the way from its center to its edge. So, when, at night, we look along the plane of this disk we see the Milky Way, while looking in the other directions, that is, uh, out of the plane, we see far fewer stars.    Because our Solar Systemis in one of the spiral arms, the Orion Arm, from our position, the center of the Galaxy is completely obscured by dust clouds; as a result, optical maps give only a limited view of the Galaxy. However, a more complete picture can be obtained by studying radio, infrared, and other radiation.    According to radio and infrared observations eliciting the nuclear properties of the Galaxy, the Galaxy's central bulge is a relatively small, dense sphere that contains mainly older red and yellow stars. The halo is a less dense region in which the oldest stars are situated; some of these stars may be as old as the Galaxy itself! The spiral arms contain mainly hot, young, blue stars, as well as nebulae inside which stars are born. These young stars span an age range between a million and ten billion years. There is also growing evidence for a very massive black hole at the center of the bulge.    The Galaxy is vast -- about 100,000 light-years across. A light-year is about 5,879 billion miles. In comparison, the Solar System seems tiny, at about 12 light-hours across, which is still about whopping 8 billion miles! As a guide to the relative physical scale of the Milky Way, if the Galaxy were reduced to 1,000 miles in diameter, the solar system would be a mere 1 inch (2.54 cm) in width.    The entire Galaxy is also rotating around its center in space, although the inner stars travel faster than those further out. The Sun, which is, as I said, about two-thirds out from the Galaxy's center, completes one lap of the Galaxy about every 220 million years. Which means, it rotates at a speed of roughly 220 kilometers per second or 800,000 kilometers per hour!
CD 2-29
Narrator: Listen as the professor leads a discussion in a geology class.     Professor: Fossils are the mineralized remains of animals, plants, and other organisms or other artifacts such as footprints. The totality of fossils and their placement in fossiliferous, or "fossil-containing," rock formations and sedimentary layers, or strata, is known as the fossil record. The study of fossils is called paleontology. By the way, the word fossil is derived from the Latin word fossus, which means "having been dug up."    Fossils usually consists of traces of the remains of the organism itself. However, fossils may also consist of the marks left behind by the organism while it was alive, such as the footprint or faces of a dinosaur or reptile. These types of fossil are called trace fossils, as opposed to body fossils. Finally, past life leaves some evidence that cannot be seen but can be detected in the form of chemical signals; these are known as chemical fossils, for lack of better term.     Fossilization is actually a rare occurrence because natural materials tend to decompose and be recycled. In order for an organism to be fossilized, the remains normally need to be covered by sediment as soon as possible. There are several different types of fossils and fossilization processes. The detailed explanations are in the handout I gave you last week. Do you have any questions about any of them? No, okay, then. Let's take a closer look of some of them. Okay, class, what is permineralization?     Male student 1: Permineralization is ...uh, this process consists of literally turning an organism into stone. The organism gets covered by sediment soon after death, or after the initial decaying process. Once covered with sediment, these layers slowly compact to rock, and the chemicals in the remains are slowly replaced with hard minerals.     Professor: Uh huh. As the organism continues to decay slowly, water infused with minerals passes through it, replacing the chemicals in it with rock-like minerals. The degree to which the remains have decayed when covered, determines the later details of the fossil. Therefore, while some fossils only consist of skeletal remains or teeth, others contain traces of skin, feathers or even soft tissues!    Let's talk about trace fossils next. Trace fossils are those details preserved in rocks that are indirect evidence of life, as it were. While we are most familiar with relatively spectacular fossils of hard part remains such as shells and bones, trace fossils are often less dramatic, but nonetheless very important. They are mainly the remains of burrows, footprints, eggs and shells, nests and droppings. Among them, coprolites, the fossilized feces, are very important because they can give, uh, insight into the feeding behavior of animals.     Another thing is, the study of trace remains is also very challenging, since many trace remains cannot be positively assigned to a specific organism. Further, trace remains such as burrows can make the work for paleontologists and geologist more difficult because older strata are easily mixed with younger ones. This can cause some confusion in interpretation unless viewed in context. There are two main kinds of trace fossils -- molds and casts -- right? Who can explain this?     Male student 2: A cast fossil is a fossil that retains the shape of the original object. The dinosaur bones you see at a museum are examples of cast fossils. If the burial of the organism was rapid, then chances are good that even impressions of soft tissues remain. A cast is a 3-D example of an object of the past created when a mold fills up with sediment like mud, sand or volcanic ash. A mold fossil is like an impression. The original object is no longer there, but a mold of its shape is. Fossilized footprints and many plants are preserved as mold fossils. A mold forms when something is pressed into soft mud and removed by decomposition or pulled out, leaving an impression of the object.     Professor: Good. Okay, then. Let's talk about "pseudofossils" and "transitional fossils," shall we? I know they are kind of confusing. Let's hear the definitions first. Debby?     Female student: Uh, okay. Pseudofossils are inorganic objects, markings, or impressions that might be mistaken for fossils. These are regular patterns in rocks, which are produced by natural occurring process. These pseusofossils can be formed by naturally formed cracks in the rock that get filled up by percolating minerals. They can easily be mistaken for real fossils.     Professor: Why's that?     Female student: Um, because some types of mineral deposits can mimic life-forms by forming what appear to be life, uh, highly detailed or organized structures. They can be very misleading.     Professor: Good, good. You must've seen crystal growth of frost on a window before. When crystals grow they form a tree-like shape. This type of mineral mass found in sedimentary rock are sometimes thought to be fossils, and occasionally one contains a fossil, but they are generally not fossils themselves.     Male student 1: Buy why do you still call them "fossils"?    Professor: Pseudofossils means false fossils. You know, "pseudonym" is an assumed name. And "pseudo intellectuals" aren't the real thing. But it's good to know there is such a species around looking like one and tricking you into thinking it is one.  Likewise, we need to know about psuedofossiles just because they are often mistaken for the real stuff. As you see in the photo on Page 129, anybody without a lot of experience would take it for the imprint of a fern. You'd never guess that is inorganic. What you're looking at is, in fact, oxidized manganese that has grown on the plane between layers of sandstone. The one on the facing page looks a lot like a sand dollar you find on the beach, doesn't it?     From these photos, you can easily see that cracks, bumps, gas bubbles, and such can be difficult to distinguish from true fossils. So, debates about whether they are pseudo or true fossils can be long and difficult. For example, a certain complex lumpy form found in some rocks was thought to be a fossil of algae for a long time, until it was identified in recent lavas.    Okay, as long as we are on the confusing topic, why don't we look at transitional fossils?     Male student 2: A transitional fossil is the fossil remains of a creature that shows primitive traits of the more evolved or derived life-forms that are related to it. According to evolutionary theory, a transitional form represents an evolutionary stage.     Professor: That's right. When Charles Darwin's The Origin of Species was first published, the fossil record wasn't well known, and the claim that there was a lack of transitional fossils was perfectly reasonable. However, only two years later Archaeopteryx, which is considered by many to be the first bird was discovered and seen as a stunning triumph for Darwin's theory of common descent. Similarly, Othniel Charles Marsh, head of the Yale Peabody Museum, provided groundbreaking evidence of transitional fossils in the evolution of horses. This has been considered one of the best examples of a clear transition between species. However, anti-evolutionists and creationists argue that the many gaps in the fossil record do exist are evidence that cuts against the theory of evolution.
CD 2-41
 Narrator: Listen to a group of students having a discussion with an official of the university.    Official: Good afternoon, everyone. I'm Brian Crestwood from the University Child Care Center. Today I'll answer any questions you have about the various programs available to students with children. We have only an hour, so let's get started, shall we?    Female Student 1: Well, I heard that there are age-limits for the child care programs on campus. What are they, Mr. Crestwood?    Official: Okay, well, all depends. Uh, first of all, at this university we offer three programs for students who have children. For those of you with very young children, we have a day care program that takes infants from 3 months to 30 months. We have another program for preschool children between two and four years of age. We also have an after-school program for school-aged children who are the age six and older. Yes?    Male student: I have a ten-year-old girl. She is interested in soccer. Does this after-school program offer any sports activities?    Official: Certainly. The program offers not just sports, but crafts, outings, and tutoring, among other things, during after-school hours. They keep children up until 5:00 most of the week.    Female student 1: What are the requirement to be eligible for these?    Official: These programs are available to any student who has registered in more than three courses in the current semester. The fees are on an hourly basis. You can take a look at the fee list on the handouts I distributed. It starts from $8 for each after-school activity. But since there are all sorts of waivers you can apply for, you may be able to get the activities for nothing. Some of the waivers are listed in the handouts, but if you have any questions about those exemption plans, feel free to talk to me after the meeting.    Female student 2: No, but, uh, actually, I'm applying for an apartment in the family housing on campus. While driving by yesterday, I saw a big schoolyard near the housing complex. I may be wrong but I assume it's part of your center, what with school buses parked in front and all. Isn't it one of your facilities?    Official: Yes, that's our family-housing branch. One of the newest additions to our program.    Female student 2: That's great. It'll take only two minutes to walk across there. Is there any special program for the residents of the family housing, by any chance?     Official: I'm glad you asked. As a matter of fact, besides these campus-wide programs for regular students with children, the University Child Care Center also offers three programs for parents in family-student housing. We're very proud of these programs the university's offering for that sector of our student body. The first program is the nursery for infants and toddlers. Our nursery is open from 8 a.m. to 6 p.m. Monday to Friday for children up to four. Parents must schedule in advance the times at which they plan to drop off and pick up their children. You can leave your children with us at the nursery from 8 to 9 and pick them up from 3 on. You can sign up for this program anytime.    Female student 2: How about the costs? Oh, and where is it located?    Official: Glad to tell you there's no cost..., um, I mean, you don't need to pay for the nursery as long as the total hours for each child per week don't exceed 30 hours. Beyond that, you'll have to bear the costs at the rate of $3 per hour. Our new Child Care Center is for exclusively for the residents in the housing complexes. And, as you noticed, it's conveniently located on West Campus Road adjacent to the family-student-housing complexes. The kindergarten is on the first floor of the center. The nursery and other facilities are one floor up in the same building. We also have a walk-in health clinic next to the nursery on the same floor. All the rest of the students can use the main Child Care Headquarters at the corner of College and Davis in East campus.    And, speaking of which, the university kindergarten is our second program. This program is available to parents with children between the age of four and six years, taking up children after the nursery. I have to tell you about this kindergarten. It's great. It's fully accredited by the public school system. Our teachers are all state certified and we have the best teachers. And the curriculum either meets or surpasses the curriculum of public kindergartens. They've been doing our university proud. The kindergarten is, by the way, open from 8 a.m. to 4 p.m. on weekdays.    Official: Yes, as a matter of fact, we do. Well, that's our third program. It's an after-school childcare program. This and the other day care programs are mutually exclusive, so to speak, because this one's only offered at the family-housing facility. This is also fully accredited by the public school system. This program is not free of charge, though. Another thing is, it stays open until 7 p.m., unlike our regular daycare, which closes at 6:00. Children can stay there another hour uh... at a cost of $120 per school term. This is possible thanks to its propinquity to your residence complex.    Female student 1: Wow, that's unheard of nowadays!    Official: You mean the hours, right? I know. Isn't it fantastic?    Male student: $120 a term is not bad at all, either. You wouldn't believe how much they charge for daycare at other places in town! When can I apply for these programs?    Official: Yeah, all of the fees are quite reasonable. Unfortunately, however, enrollment in these programs at the Child Care Center is limited and early application is essential, well, um, since our programs often have long waiting lists, as you can imagine. If any of you new students need these services, help yourself to the brochures and forms on the desk here. Please let me know right away if you need any assistance so I can direct you to the right office to get you orientated. I have a line on every service office on campus! Oh, in case you need a duplicate of the forms or more information, another way of getting them is to download them from our website, www.umchildcare.org.    Male student: I'd better get cracking.
CD 2-54
 Narrator: Listen to part of a lecture in a social science class.    Professor: Today, I'd like to talk about the Supreme Court decision on Roe v. Wade. In 1973, in the case of Roe v. Wade, the U.S. Supreme Court ruled that a woman's constitutional right to privacy includes the right to abort a fetus during the first trimester, that is, in the first three months of pregnancy, but also that beyond three months the fetus is "viable," which means it is able to continue to live, and the state, therefore, has responsibility for protecting it.    The case was first filed by Norma McCorvey, who sued the state of Texas for denying her the right to abortion. Well, the ruling, among the most controversial in the high court's history, barred the states from prohibiting abortion in the first trimester. The ruling gave rise to opposing movements, one to preserve woman's right to have abortions, and the other to limit or deny that right. As you know, the first is called "pro-choice"; the second, "pro-life" or "right-to-life."    The decision in Roe v. Wade promoted a decades-long, spirited, and sometimes frenzied national debate, mainly over three issues. First, the legality of terminating pregnancies. Second, the role of Supreme Court in constitutional adjudication. Third, the role of religious views in the political sphere. Thus, Roe v. Wade became one of the most politically significant Supreme Court decisions in history, and held profound moral and legal implications as well. The decision, consequently, reshape national politics, divided the nation, and inspired grassroots activism.     Did anyone watch the Senate confirmation hearings of Judge Alito? Okay, many of you did. Good. At one point the whole procedure turned quite confrontational. Do you remember? Even Alitos wife fled the hearing room in tears. What was the bone of contention?    Male Student 1: Um, Democratic Senators were criticizing him for giving incomplete and inconsistent answers the whole time.     Professor: Yeah, he certainly sounded evasive sometimes ...    Male Student 2: And, uh, Democratic Senators got exited over his comment ... What did he say? Something like "I would be willing to reverse," ...uh, "to revisit the ruling," I think. I mean, besides his hedging questions. He didn't really answer the will-he-or-won't-he question about the decision on Roe v. Wade.    Professor: Yes, that's more like it.    Female Student: But that's not all. He was accused of being a sexist, too. You remember? He's a member of an alumni group that wanted to restrict enrollment of women and minorities.      Professor: Well, there's a definite connection between these two issues, isn't there, Laura? Here, I think, the main source of contention was his comment to the effect that he might be willing to revisit the decision that legalized abortion nationwide. What this means is, he left the door open to reversing the decision.    As you witnessed in Judge Alito's case, the question of adherence to the decision has since been the liberals' so-called litmus test for Supreme Court nominees in the Senate confirmation hearings. Speaking generally, opposition to Roe came from those who view the court's decision as illegitimate for straying too far from the Constitution, and those who conceive of the fetus as an entire person. Support for Roe comes from those who women's rights and personal freedom, and those who believe in the primacy of individual over collective rights.    Let's turn the clock back and take a look at the debate's background history. Well, we tend to get easily bogged down by current affairs only and are unable to see the whole picture. I think it's very illuminating to see how abortion was regarded before it became a highly political issue. So here we go.    Since before the time of the American Revolution, the legal status of abortion has indeed gone through various changes. Under colonial and early American law, abortion was legal, provided that it was carried out before movements of the fetus could be felt -- which is, well, generally about midway through a pregnancy. In the 1830s, abortion was widespread as a method of birth control. If you check newspapers and magazines from this era, you will find that they routinely and matter-of-factly discussed the topic with their doctors. By the 1860s, doctors estimated that women had abortions at the rate of one for every four live births.     In the 1860s, however, the newly created American Medical Association began -- for professional, ethical, and hygienic reasons -- a campaign to outlaw abortions, except when deemed necessary by doctors themselves. Then, a wave of legislative reform followed. These new laws sent abortionists underground, but substantial numbers of women continued to have abortions throughout the nineteenth century and into the twentieth.     In the 1950s, the movement to repeal state laws banning abortions was begun in a context over the postwar "population explosion." Vehemently opposed to such liberalization were groups like the Roman Catholic Church and various fundamentalist and evangelical Protestants.    In this state of constant face-off, in 1973, a case was filed by Norma McCorvey. She sued the state of Texas for denying her right to an abortion. "Jane Roe," a standard alias for anonymous plaintiffs, was used to protect her identity. The Supreme Court ruled the case of Roe v. Wade in her favor, and all states were directed to lift their bans on abortions, though many resisted actually doing so. When the case reached the Supreme Court, few people expected the justices to overturn the Texas law. That was because the court had become increasingly conservative with the appointments by President Richard Nixon of Chief Justice Warren Burger and Justice Harry Blackmon, Lewis Powell, and William Rehnquist, and the retirement of Chief Justice Earl Warren, and the details of Hugo Black and John Marshall Harlan 2 -- all judicial liberals.    Roe v. Wade, important in itself, also raised issues concerning the degree to which the federal government could judge, uh, the federal government could legislate the worst private and fundamental issues of life and death, um, including the question of when life begins. This is the question that has proved to be political dynamite, as we all know very well by now, and that is and will be debated by scientists, moralists, and theologians for many years to come. That's about the only thing agreed upon about the whole thing.