Reading Comprehension- Science passages

The Passage A meteor stream is composed of dust particles that have been ejected from a parent comet at a variety of velocities. These particles follow the same orbit as the parent comet, but due to their differing velocities they slowly gain or fall behind the disintegrating comet until a shroud of dust surrounds the entire cometary orbit. Astronomers have hypothesized that a meteor stream should broaden with time as the dust particles’ individual orbits are perturbed by planetary gravitational fields. A recent computer-modeling experiment tested this hypothesis by tracking the influence of planetary gravitation over a projected 5,000-year period on the positions of a group of hypothetical dust particles. In the model, the particles were randomly distributed throughout a computer simulation of the orbit of an actual meteor stream, the Geminid. The reseNavigator found, as expected, that the computer-model stream broadened with time. Conventional theories, however, predicted that the distribution of particles would be increasingly dense toward the center of a meteor stream. Surprisingly, the computer-model meteor stream gradually came to resemble a thick-walled, hollow pipe. Whenever the Earth passes through a meteor stream, a meteor shower occurs. Moving at a little over 1,500,000 miles per day around its orbit, the Earth would take, on average, just over a day to cross the hollow, computer-model Geminid stream if the stream were 5,000 years old. Two brief periods of peak meteor activity during the shower would be observed, one as the Earth entered the thick-walled pipe and one as it exited. There is no reason why the Earth should always pass through the stream’s exact center, so the time interval between the two bursts of activity would vary from one year to the next. Has the predicted twin-peaked activity been observed for the actual yearly Geminid meteor shower? The Geminid data between 1970 and 1979 show just such a bifurcation, a secondary burst of meteor activity being clearly visible at an average of 19 hours (1,200,000 miles) after the first burst. The time intervals between the bursts suggest the actual Geminid stream is about 3,000 years old. Here’s how to read When you’re reading an RC passage, think about: (1) What words or parts of the sentence are so complex that you are going to ignore them for now? (2) When can you stop reading and start skimming? (3) When do you have to start paying close attention again?   Let’s try paragraph 1: Original Text A meteor stream is composed of dust particles that have been ejected from a parent comet at a variety of velocities. These particles follow the same orbit as the parent comet, but due to their differing velocities they slowly gain or fall behind the disintegrating comet until a shroud of dust surrounds the entire cometary orbit. What I thought I’ve heard the word meteor before. I know what a comet is. Halley’s Comet is the really famous one. When you see a picture of a comet, it has a tail of little dots of light”I guess that’s part of the meteor stream thing. Original text Astronomers have hypothesized that a meteor stream should broaden with time as the dust particles’ individual orbits are perturbed by planetary gravitational fields. A recent computer-modeling experiment tested this hypothesis by tracking the influence of planetary gravitation over a projected 5,000-year period on the positions of a group of hypothetical dust particles. What I thought The hypothesis is that the stream should get bigger or more spread out”not really sure”for some reason and a recent experiment tests this on a hypothetical case Original Text In the model, the particles were randomly distributed throughout a computer simulation of the orbit of an actual meteor stream, the Geminid. The reseNavigator found, as expected, that the computer-model stream broadened with time. Conventional theories, however, predicted that the distribution of particles would be increasingly dense toward the center of a meteor stream. Surprisingly, the computer-model meteor stream gradually came to resemble a thick-walled, hollow pipe. What I thought I don’t understand the significance of the first sentence, but it sounds like they tried to map a real meteor stream, the Geminid.They hypothesized that the stream would broaden and it did.BUT. They also predicted something else that I don’t really understand and then something surprising happened. The meteor stream looked like a certain kind of pipe. I know what a pipe is, so I can visualize that, but I don’t really understand what they’re trying to say here.   Notice a few things. First, most of the bold words are normal words”not the crazy technical ones. Second, I’m not entirely sure what’s going on at the end of that first paragraph; the information is getting pretty detailed. And I don’t care! It’s okay not to understand that level of detail at this point. I know that the conventional theories and the computer-model test agree on one thing but something else was surprising. Paragraph 2 Original Text Whenever the Earth passes through a meteor stream, a meteor shower occurs. What I thought Is this like the Northern Lights? Or maybe shooting stars? Bright lights in the night sky”okay, this makes sense. This stuff comes into the Earth’s atmosphere and then we see it. Original Text Moving at a little over 1,500,000 miles per day around its orbit, the Earth would take, on average, just over a day to cross the hollow, computer-model Geminid stream if the stream were 5,000 years old. What I thought Hypothetical language. IF the model is right, and if this Geminid thing is 5,000 years old, then something would take about a day to happen”maybe there would be meteor showers for a day? (Note: how did I know to ignore the starting words? It’s a modifier, not the subject. Use your SC skills!) Original text Two brief periods of peak meteor activity during the shower would be observed, one as the Earth entered the thick-walled pipe and one as it exited. There is no reason why the Earth should always pass through the stream’s exact center, so the time interval between the two bursts of activity would vary from one year to the next. What I thought Still hypothetical. Enter and exit I don’t get it. Read the next sentence. Oh, there are two bursts of activity with some time in between. Okay. Most of the sentences were pretty detailed and confusing. I still don’t get the whole enter and exit thing, but that’s okay for now. Paragraph 3 Original Text Has the predicted twin-peaked activity been observed for the actual yearly Geminid meteor shower? What I thought The model predicted something. Does it match reality? Original Text The Geminid data between 1970 and 1979 show just such a bifurcation, a secondary burst of meteor activity being clearly visible at an average of 19 hours (1,200,000 miles) after the first burst. The time intervals between the bursts suggest the actual Geminid stream is about 3,000 years old. What I thought Not sure what they mean by bifurcation, but the data show just such something means that the data did show something that was expected. I’ll figure out later what that was (if I get a question about it).Hmm, and the G is 3,000 years old, so this must be talking about something similar to that 5,000 year comment earlier. So the predicted activity did seem to match reality in some way, but the Geminid is only about 3,000 years old. Taking Notes Here’s one example of a possible set of notes (but these will vary widely!) P1 MS around cometsame orbit, diff velocmodel of G vs. theory P2 Earth + MS = showeractivity varies (?) P3 model = reality? Y. (?)G 3,000 yo The two question marks in parentheses are used to indicate There’s more detail here that I don’t quite understand”I’ll come back to it if / when I get a question about it. Our notes are so skimpy! Notice how much we don’t know. This is exactly where we want to be at this point in the passage. We have the big picture and we have a pretty good idea of where to go if we get asked about certain topics. The computer model vs. the conventional theories? Mid-to-late paragraph 1. A surprising result? End of paragraph 1. Something about the amount of activity or how old the MS is? Prediction or hypothetical is paragraph 2 and reality is paragraph 3. You’re not actually done reading, though. When you get a question about a particular detail, you will go back and read that information to try to figure out the answer. You’re just deferring”you’re going to get into the detail later, not right now during the initial read-through. Why? There’s just not enough time. Luckily, we know that we aren’t going to get asked about all of these details “ only some of them. So why bother to learn those annoying details unless and until we know that we need them?   Key Takeaways for Reading the Passage (1) Half of the battle on RC is knowing what to read and what not to read. Concentrate on the core: the main subjects and verbs. Skim over the modifiers and details on the first read-through; you’ll come back to these later (IF you get a question about them). (2) The bigger the words and the more complicated the sentences, the more likely we’ll want to skim. They’re going to use technical terms, such as cometary in paragraph 1, and they’ll toss in long modifiers to slow us down. A recent computer-modeling experiment? How about just an experiment? (3) Anticipate whenever you can. Astronomers have hypothesized A recent experiment tested this hypothesis. Okay, they’re probably going to tell me whether the results helped or hurt the hypothesis. I’m going to keep an eye out for that.