Narrator: Listen to a conversation between a student and the faculty advisor of the campus newspaper .
Student: Hi! I talked to someone on the phone a couple of weeks ago, Anna , I think it was?
Advisor: I’m Anna, the faculty advisor.
Student: Oh, great! I’m Peter Murphy. You probably don’t remember me, but …
Advisor: No! No! I remember you. You’re interested in working for the paper.
Student: Yeah, as a reporter.
Advisor: That’s right. You’re taking a journalism class and you’ve done some reporting before in high school, right?
Student: Wow, you have a good memory.
Advisor: Well we haven’t had many students applying lately so … so anyway, you still want to do some reporting for us?
Student: Yeah, if you have room for me on the staff.
Advisor Well we always need more reporters, but you know, we don’t pay anything, right?
Student: Yeah, I know, but I huh.. . I’d like the experience. It would look good on my resume.
Advisor: Absolutely! Let’s see. I think I told you that we ask prospective reporters to turn in some outlines for possible articles.
Student: Yeah, I sent them in about a week ago, but I haven’t heard anything back yet, so, so I thought I’d stop by and see, but I guess you haven’t looked at them yet.
Advisor: OH, Max, the news editor. He looks a t all the submissions.
Student: Oh , so he hasn’t made any decision about me yet?
Advisor: Well I just got here a few minutes ago… haven’t been in for a couple of days. Just give me a second to check my e-mail.
Uh … here is a message from Max. Let’s see. Well it seems you’ve really impressed him. He says it would be wonderful if you could join our staff.
Student: Oh, great! When can I start?
Advisor: We’ll, you turned in an outline on something to do with the physics department?
Student: Yeah, they’re trying to come up with ways to get more students to take their introductory courses.
Advisor: Right, well , apparently, nobody else is covering that story , so he wants you to follow up on it.
Student: OK. Uh … what the other outline I sent in, about the proposed increase in tuition fees?
Advisor: Oh, it lo oks like we’ve got that covered.
Student: So I am starting with an article about the physics department. I guess I’d better get to work. Do you have any advice on how I should cover the story?
Advisor: Well, Max will want to talk to you but I am sure he will tell you to find out things like why the physics department’s worried about enrollment.
Has the number of students been getting smaller in recent years? By how much? What kinds of plans are they considering to address this problem?
Student: Right, some of those issues are already in what I proposed.
Advisor: And you’ll want to do some interviews, you know, what do the professors think of the plans, what do the students think you get the idea but …
Student: But wait till I talk to Max before proceeding.
Advisor: Right, he’ll cover everything you need to know to be a report e r for us .Can you come back this afternoon? He will be here until 5 o’clock.
Narrator: Listen to part of a conversation between a student and her biology professor.
Professor: Hi Samantha, how did your track meet go?
Samantha: Great! I placed first in one race and third in another.
Professor: Congratulations! You must practice a lot.
Samantha: Three times a week pre-season, but now that we’re competing every weekend, we practice 6 days a week from 3:30 till 5:00.
Professor: Athletics place a heavy demand on your time, don’t they?
Samantha: Yeah, but I really love competing, so …
Professor: You know I played soccer in college and my biggest challenge,
and I didn’t always succeed, was getting my studying in during soccer season. Are you having a similar …?
Samantha: No, I … I really do make time to study. And I actually study more for this class than I do for all my other classes.
But I didn’t see the grade I expected on my mid-term exam, which is why I came by.
Professor: Well, you “didn’t do badly on the exam, but I agree it did not reflect your potential. I say this because your work on the lab project was exemplary.
I was so impressed with the way you handle the microscope and the samples of onion cells,
and with how carefully you observed and diagramed and interpreted each stage of cell division.
And I don’t think you could have done that if you hadn’t read and understood the chapter. I mean it seemed like you really had a good understanding of it.
Samantha: I thought so too, but I missed some questions about cell division on the exam.
Professor: So what happened?
Samantha: I just sort of blanked out, I guess. I had a hard time remembering details. It was so frustrating.
Professor: Alright, let’s back up. You say you studied, where, at home?
Samantha: At my kitchen table actually.
Professor: And that’s supposed to be a quiet environment?
Samantha: Not exactly. My brother and parents try to keep it down when I am studying, but the phone pretty much rings off the hook, so …
Professor: So you might try a place with fewer distractions, like the library …
Samantha: But the library closes at mid-night, and I like to study all night before a test, you know, so everything is fresh in my mind.
I studied six straight hours the night before the mid-term exam . That’s why I expected to do so much better.
Professor: Oh ok. You know that studying six consecutive hours is not equivalent to studying one hour a day for six days.
Samantha: It isn’t?
Professor: No. There is research that shows that after about an hour of intense focus, your brain needs a break.
It needs to, you know, shift gears a little.
Your brain’s ability to absorb information starts to decline after about the first hour.
So if you are dealing with a lot of new concepts and vocabulary, anyway, if you just reviewed your notes, even 20 minutes a day,
it’d be much better than waiting until the night before an exam to try and absorb all those details.
Samantha: Oh, I didn’t realize.
Professor: Think of your brain as: a muscle. If you didn’t practice regularly with your track team,
and then tried to squeeze in three weeks worth of running practice just the day before a track meet,
how well do you think you’d perform in your races?
Narrator: Listen to part of a lecture in a psychology class.
Professor: For decades, psychologists have been looking at our ability to perform tasks while other things are going on,
how we are able to keep from being distracted and what the conditions for good concentration are.
As long ago as 1982, researchers came up with something called the CFQ -the Cognitive Failures Questionnaire.
This questionnaire asks people to rate themselves according to how often they get distracted in different situations, like h um …..
Forgetting to save a computer file because they had something else on their mind or missing a speed limit sign on the road. John?
John: I’ve lost my share of computer files, but not because I’m easily distracted. I just forget to save them.
Professor: And that’s part of the problem with the CFQ. It doesn’t take other factors into account enough, like forgetfulness.
Plus you really can’t say you are getting objective scientific results from a subjective questionnaire where people report on themselves.
So it’s no surprise that someone attempted to design an objective way to measure distraction. It’s a simple computer game designed by a psychologist named, Nilli Lavie.
In Lavie’s game, people watch as the letters N and X appear and disappear in a certain area on the computer screen.
Every time they see an N, they press one key, and every time they see an X they press another,
except other letters also start appearing in the surrounding area of the screen with increasing frequency which creates a distraction and makes the task more difficult.
Lavie observed that people’s reaction time slowed as these distractions increased.
Student 2: Well that’s not too surprising, isn’t it?
Professor: No, it’s not. It’s the next part of the experiment that was surprising.
When the difficulty really increased, when the screen filled up with letters, people got better at spotting the Xs and Ns .
What do you think that happened?
John: Well, maybe when we are really concentrating, we just don’t perceive irrelevant information. Maybe we just don’t take it in, you know?
Professor: Yes, and that’s one of the hypotheses that was proposed, that the brain simply doesn’t admit the unimportant information.
The second hypothesis is that, yes, we do perceive everything, but the brain categorizes the information,
and whatever is not relevant to what we are concentrating on gets treated as low priority.
So Lavie did another experiment, designed to look at the ability to concentrate better in the face of increased difficulty.
This time she used brain scanning equipment to monitor activity in a certain part of the brain, the area called V5,
which is part of the visual cortex, the part of our brains that processes visual stimuli.
V5 is the area of the visual cortex that’s responsible for the sensation of movement. Once again, Lavie gave people a computer-based task to do.
They have to distinguish between words in upper and lower-case letters or even harder, they had to count the number of syllables in different words.
This time the distraction was a moving star field in the background, you know, where H looks like you are moving through space, passing stars.
Normally area of V5 would be stimulated as those moving stars are perceived and sure enough,
Lavie found that during the task area of V5 was active, so people were aware of the moving star field.
That means people were not blocking out the distraction.
Student 1: So doesn’t that mean that the first hypothesis you mentioned was wrong, the one that says we don’t even perceive irrelevant information when we are concentrating?
Professor: Yes that’s right, up to a point, but t that’s not all.
Lavie also discovered that as she made the task more difficult, V5 became less active, so that means that now people weren’t really noticing the star field at all.
That was quite a surprise and it approved that the second hypothesis –
that we do perceive everything all the time but the brain categorizes distractions differently, well, that wasn’t true either.
Lavie thinks the solution lies in the brain’s ability to accept or ignore visual information. She thinks its capacity is limited.
It’s like a highway. When there are too many cars, traffic is stopped. No one can get on. So when the brain is loaded to capacity, no new distractions can be perceived.
Now that maybe the correct conclusion for visual distractions, but more research is needed to tell us how the brain deals with, say,
the distractions of solving a math problem when we are hungry or when someone is singing in the next room.
Narrator: Listen to part of a lecture in a geology class.
Professor: As geologists, we examine layers of sediment on the Earth’s surface to approximate the dates of past geologic time periods.
Ah sediment as you know i s material like sand, gravel, fossil fragments that is transported by natural processes like wind, water flow or the movement of glaciers.
So sediment is transported and then deposited and it forms layers on the Earth’s surface over time.
We examine these layers to learn about different geologic time periods including when they began and ended.
For example, from about 1.8 million years ago to around 11 thousand years ago was the Pleistocene epic.
The Pleistocene epic was an ice age.
During this epic, sediment was made by the kind of erosion and we athering that happens when the climate is colder,
and part of those sediments are fossils of plants and animals that lived at that time.
The Holocene epic followed the Pleistocene epic when the Earth’s climate warmed up around 11 thousand years ago.
The Holocene epic is characterized by different sediments, ones that form when the climate is warmer.
Because the climate changed, the types of plants and animals changed also.
Holocene sediments contain remnants of more recent plants and animals, so it’s pretty easy to differentiate geologically between these two epics.
Now there is growing evidence that the presence of humans has altered the earth so much that a new epic of geologic history has begun –
the Anthropocene epic, a new human-influenced epic.
This idea that we’ve entered a new Anthropocene epic was first proposed in 2002.
The idea is that around the year 1800 CE the human population became large enough, around a billion people, that its activities started altering the environment.
This was also the time of the industrial revolution, which brought a tremendous increase in the use of fossil fuels such coal.
The exploitation of fossil fuels has brought planet wide developments: industrialization, construction, uh, mass transport.
And these developments have caused major changes like additional erosion of the Earth’s surface and deforestation.
Also, things like the damming of rivers, has caused increased sediment production, not to mention the addition of more carbon dioxide and methane in the atmosphere.
Naturally all these changes show up in recent sediments. And these sediments are quite different from pre year 1800 sediment layers.
Interestingly there’s some speculation that humans started having a major impact on Earth much earlier, about 8000 years ago.
That’s when agriculture was becoming widespread. Early farmers started clearing forests and livestock produced a lot of extra methane.
But I want to stress this is just a hypothesis. The idea that early humans could have had such a major effect,
well I’m just not sure we can compare it with the industrial age.
Geologists in the far future will be able to examine the sediment being laid down today, whereas right now we can say that yes,
human impact on the Earth is clear:
It’ll be future researchers who have better perspective and will be able to really draw a line between the Holocene and the Anthropocene epics.
Narrator: Listen to part of a lecture in an art history class.
Professor: Now in Europe in the Middle Ages before the invention of printing and the printing press, all books, all manual scripts were hand-made.
And the material typically used for the pages was parchment, which is animal skin that stretched and dried under tension, so it become s really fat and can be written on.
During the 1400s, when printing was being developed, paper became the predominant material for books in Europe, but prior to that, it was parchment.
Parchment is durable, much more so than paper, and it could be reused which came in handy since it was a costly material and in short supply.
So it wasn’t uncommon for the scribes or monks who produce the manual scripts. Ah, remember before printing books were made mainly in monasteries.
Well, the scribes often recycled the parchment that’d been used for earlier manual scripts.
They simply erased the ink off the parchment and wrote something new in its place a manual script page that was written on, erased and then used again is called a palimpsest.
Palimpsests were created, well, we know about two methods that were used for removing ink from parchment.
In the late Middle Ages, it was customary to scrape away the surface of the parchment with an abrasive,
which completely wiped out any writing that was there.
But earlier in the Middle Ages, the original ink was usually removed by washing the used parchment with milk.
That removed the ink. But with the passing of time, the original writing might reappear.
In fact, it might reappear to the extent that scholars could make out an even decipher, the original text.
Perhaps, the most famous example is the Archimedes’ palimpsest.
Archimedes li v e d in Greece around 200 BCE,
and as you probably know, he’s considered one of the greatest Mathematicians who ever lived,
even though , many of his writings had been lost , including what many now think to be his most important work called The Method.
But in 1998, a book of prayers from the Middle Ages sold in an art auction for a lot of money, more money than anyone would pay for a damaged book from the 12th century. Beautiful or not, why?
It had been discovered that the book was a palimpsest, and beneath the surface writing on the manual script laid, guess what?
Mathematical theorems and diagrams from Archimedes
Archimedes’ writings were originally done on papyrus scrolls.
Then in the10th century, a scribe made a copy on parchment of some of his texts and diagrams including, as it turns out the Method.
This was extremely fortunate, since later on, the original papyrus scrolls disappeared.
About 200 years later in the 12th century, this parchment manual script became a palimpsest when a scribe used the parchment to make a prayer book.
So the pages, the pieces of parchment themselves, had been preserved. But the Archimedes’ text was erased and written over, and no one knew it existed.
It wasn’t until 1906 that a scholar came across the prayer book in a library and realized it was a palimpsest,
and that the underlying layer of texts could only have come from Archimedes.
That was when his work The Method was discovered for the first time.
Um… the palimpsest then went through some more tough times,
but eventually it ended up in an art auction where was bought and then donated to an art museum in Baltimore, for conservation and study.
To avoid further damage to the manual script, the research team at the art museum has had to be extremely selective in their techniques they used to see the original writing.
They’ve used ultraviolet light and some other techniques, and if you’re interested in that sort of thing, you can learn more about it in an art conservation class.
But actually, it was a physicist who came up with a method that was a breakthrough.
He realized that the iron in the ancient ink would display if exposed to a certain X-ray imaging method,
and except for small portions of the text that couldn’t be deciphered,
this technique’s been very helpful in seeing Archimedes ‘texts and drawings through the medieval over writing.
Narrator: Listen to part of a lecture in a biology class.
Professor: OK. We’ve been talking till now about the two basic needs of a biological community –
an energy source to produce organic materials, you know ah, food for the organism, and the waste recycling or breakdown of materials back into inorganic molecules,
and about how all this requires photosynthesis when green plants or microbes convert sunlight into energy and also requires microorganisms, bacteria,
to secrete chemicals that break down or recycle the organic material to complete the cycle.
So, now we are done with this chapter of the textbook, we can just review for the weekly quiz and move on to the next chapter, right?
Well, not so fast. First, I’d like to talk about some discoveries that have challenged one of these fundamental assumptions about what you need in order to have a biological community.
And, well, there actually were quite a few surprises. It all began in 1977with the exploration of hydrothermal vents on the ocean floor.
Hydrothermal vents are cracks in the Earth’s surface that occur, well, the ones we are talking about here are found deep at the bottom of the ocean.
And these vents on the ocean floor, they release this incredibly hot water, 3-4 times the temperature that you boil water at because this water has been heated deep within the Earth.
Well about 30 years ago, researchers sent a deep-sea vessel to explore the ocean’s depth, about 3kilometers down, way deep to ocean floor,
No one had ever explored that far down before. Nobody expected there to be any life down there because of the conditions.
First of all, sunlight doesn’t reach that far down so it’s totally dark.
There couldn’t be any plant or animal life since there’s no sunlight, no source of energy to make food.
If there was any life at all, it’d just be some bacteria breaking down any dead materials that might have fallen to the bottom of the ocean. And?
Student 1: And what about the water pressure? Didn’t we talk before about how the deeper down into the ocean you go, the greater the pressure?
Professor: Excellent point! And not only the extreme pressure, but also the extreme temperature of the water around these vents.
If the lack of sunlight didn’t rule out the existence of a biological community down there then these factors certainly would, or so they thought.
Student 2: So you are telling us they did find organisms that could live under those conditions?
Professor: They did indeed, something like 300 different species.
Student 1: But… but how could that be? I mean without sunlight, no energy, no no …
Professor: What they discovered was that microorganisms, bacteria, had taken over both functions of the biological community – the recycling of waste materials and the production of energy.
They were the energy source. You see, it turns out that certain microorganisms are chemosynthetic -they don’t need sunlight because they take their energy from chemical reactions.
So, as I said, unlike green plants which are photosynthetic and their energy from sunlight, these bacteria that they found at the ocean floor, these are chemosynthetic,
which means that they get their energy from chemical reactions.
How does this work? As we said, these hydrothermal vents are releasing into the ocean depth this intensely hot water and here is the thing,
this hot water contains a chemical called hydrogen sulfide, and also a gas, carbon dioxide.
Now these bacteria actually combine the hydrogen sulfide with the carbon dioxide and this chemical reaction is what produces organic material which is the food for larger organisms.
The researchers had n ever seen anything like it before.
Student 2: Wow! So just add a chemical to a gas, and bingo, you’ve got a foodsupply?
Professor: Not just that! What was even more surprising were all the large organisms that lived down there.
The most distinctive of these was something called the tube worm. Here, let me show you a picture.
The tube of the tube worm is really, really long. They can be up to one and half meters long, and these tubes are attached to the ocean floor, pretty weird looking, huh?
And another thing, the tube worm has no. mouth, or digestive organs. So you are asking how does it eat.
Well, they have these special organs that collect the hydrogen sulfide and carbon dioxide and then transfer it to another organ, where billions of bacteria live.
These bacteria that live inside the tube worms, the tube worms provide them with hydrogen sulfide and carbon dioxide.
And the bacteria, well the bacteria kind of feed the tube worms through chemosynthesis, remember that chemical reaction I described earlier.