How an article links and separates people, ideas and events

Grade 8 Reading Worksheet

Circle the best answer.

1. Read this first

   Weather and Climate (article)

   [1] People often use the words weather and climate as if they meant the same thing, but scientists keep them carefully apart. [2] Weather describes what the atmosphere is doing at a certain place and time, such as a rainy afternoon or a windy morning. [3] Climate is the pattern of weather in a region over many years, and scientists usually average at least thirty years of records.

   [4] One way to keep the two ideas apart is to compare weather with a mood and climate with a personality. [5] A mood can shift within minutes, just as a calm morning can turn stormy by noon, while a personality stays largely the same across years. [6] A place with a dry, sunny climate can still have a gloomy, rainy week, in the same way a cheerful person can have a bad day.

   [7] The comparison explains why a single cold morning does not disprove a warming climate. [8] One cold morning is a point of weather, but climate is the average of thousands of such days, and an average moves slowly. [9] Scientists therefore watch long records, looking for a rise or fall that lasts after the ordinary swings have been averaged out.

   [10] This distinction matters when people read about changing temperatures. [11] A forecast for next week and a projection fifty years ahead answer different questions, and each relies on different evidence. [12] The first uses the current state of the air, while the second uses long records and what scientists know about how the planet holds heat.

2. 1.

   Ari labels the link between paragraph 2 and paragraph 3. Which choice gives the right label and the right reason?

   • Like: paragraph 2 compares weather to a mood that changes and climate to a personality that lasts, and paragraph 3 uses that same likeness to explain why one cold morning does not change a climate.
   • Like: paragraph 2 compares weather to a mood, and paragraph 3 shows that climate cannot change, since an average stays put.
   • Unlike: paragraph 2 compares weather to a mood that changes and climate to a personality that lasts, and paragraph 3 says one cold morning is the opposite of a mood, so the likeness has ended and the two ideas are unrelated.
   • Like: in paragraph 1 the article says weather and climate are different ideas, and in paragraph 4 it says a forecast and a projection answer different questions.
3. 2.

   Bo asks why the author compares weather to a mood and climate to a personality. What does the comparison help a reader understand?

   • That climate cannot change, because a personality stays the same for the whole of a lifetime.
   • That weather is what the air is doing at one place and time, such as a rainy afternoon or a windy morning, which is why it changes so quickly.
   • Why one cold day, like a passing mood, says little about a climate, which is the lasting pattern of a place.
   • That scientific words can be explained with everyday ideas that most people already know well.

4. Three Families of Rock (article)

   [1] Geologists sort rocks into three families according to how they formed, not how they look. [2] Each family name describes the process that made its rocks. [3] Granite and basalt are igneous rocks, because both began as molten rock that cooled and hardened. [4] Sandstone and limestone are sedimentary rocks, built from layers of sand, mud or shell fragments that were pressed together over time.

   [5] The third family is created when rocks change without fully melting. [6] Marble and slate are metamorphic rocks, formed when heat and pressure deep underground transform an older rock, limestone in the case of marble and shale in the case of slate. [7] The word metamorphic comes from a Greek phrase meaning changed form.

   [8] The classification explains differences that appearance alone would hide. [9] Granite cooled slowly underground, which gave its crystals time to grow large enough to see, while basalt cooled quickly at the surface and has crystals too small to notice. [10] Sedimentary rocks often hold fossils, but the heat that forms igneous and metamorphic rocks usually destroys them. [11] Many metamorphic rocks show bands of minerals that were squeezed into layers by the pressure.

   [12] The families are also connected in a cycle. [13] A mountain of granite can be worn into sand, the sand can be buried and pressed into sandstone, and deep heat can turn the sandstone into quartzite, a metamorphic rock. [14] So a single rock can belong to a different family at different stages of its long history.

5. 3.

   Kira asks why the author sorts rocks by how they formed instead of by how they look. What does the sorting help a reader understand?

   • That the process that made a rock explains differences in crystals and fossils that its appearance alone would hide.
   • That the way a rock looks says little about the way it formed, so appearance can be ignored.
   • That sorting things into groups makes a large subject easier to study and to remember.
   • That igneous rocks began as molten rock that cooled and hardened, as granite and basalt did, while the other two families formed in different ways.
6. 4.

   Luz asks which family the article puts marble in. Which choice names the family and the reason?

   • Sedimentary, because it is built from layers of shell fragments that were pressed together, as limestone is, the rock that marble comes from.
   • Metamorphic, because it is the one family whose rocks can turn into rocks of the other two families.
   • Metamorphic, because heat and pressure deep underground changed an older rock, limestone, without fully melting it.
   • Metamorphic, because it began as molten rock that cooled and hardened.

7. Ocean Waves and Radio Waves (article)

   [1] Ocean waves and radio waves share a name, and at first glance they seem to have little else in common. [2] Both, however, carry energy from one place to another without carrying the material itself. [3] A floating cork rises and falls as an ocean wave passes beneath it, but the cork is not swept along, and a radio wave can cross a room without sweeping the air with it.

   [4] Both kinds of wave can also be described by the same three measurements. [5] Wavelength is the distance from one crest to the next, frequency is the number of crests that pass a point each second, and amplitude is the height of a crest above the middle. [6] A radio station is identified by its frequency, and a surfer knows that waves with large amplitude carry the most energy.

   [7] The most important difference is what each wave needs in order to travel. [8] An ocean wave is a disturbance of water, and without water it cannot exist. [9] A radio wave is a pattern of changing electric and magnetic fields, and it travels through empty space as easily as through air, which is how signals from spacecraft reach Earth.

   [10] The difference also determines speed. [11] Wind-driven ocean waves move at most a few dozen miles per hour, while radio waves travel at the speed of light, about 186,000 miles every second. [12] Despite that gap, engineers use the same mathematics to design a harbor wall and a radio antenna.

8. 5.

   Milo labels the link between paragraph 1 and paragraph 3. Which choice gives the right label and the right reason?

   • Unlike: in paragraph 1 the article says both kinds of wave carry energy, but in paragraph 3 it says a radio wave carries more energy than an ocean wave does.
   • Unlike: in paragraph 2 the article says wavelength is the distance from crest to crest, but in paragraph 4 it says radio waves travel at the speed of light, which no ocean wave comes close to.
   • Like: in paragraph 1 the article says both kinds of wave carry energy without carrying material, and in paragraph 3 it adds that both need a material such as water or air to travel through.
   • Unlike: in paragraph 1 both kinds of wave carry energy without carrying material, but in paragraph 3 an ocean wave needs water while a radio wave can cross empty space.
9. 6.

   Noah asks what paragraph 2 helps a reader understand about ocean waves and radio waves.

   • That a radio wave and an ocean wave with the same wavelength must travel at exactly the same speed as each other.
   • That a surfer can judge how much energy an ocean wave carries by how high its crest rises above the middle of the water.
   • That waves are an important idea in many parts of science and engineering, from the sea and the shore to the sky and space.
   • That one set of measurements, wavelength, frequency and amplitude, describes both ocean waves and radio waves.
10. 7.

    Pia asks which kind of wave the article says can travel through empty space. Which choice names it and gives the reason?

    • A radio wave, because empty space is the place where it travels, and air stops it.
    • An ocean wave, because it carries energy from one place to another without carrying the water along, so it needs no material to travel.
    • A radio wave, because it is a pattern of changing electric and magnetic fields instead of a disturbance of a material.
    • A radio wave, because it moves at most a few dozen miles per hour, so it needs very little room.

11. Two Kinds of Muscle Fiber (article)

    [1] Every muscle in the body is built from bundles of fibers, but the fibers are not all alike. [2] Each fiber is a single long cell that is controlled by one nerve ending. [3] Physiologists divide fibers into two main types, which they call slow-twitch and fast-twitch. [4] The names describe how quickly a fiber contracts after a nerve signal reaches it.

    [5] Slow-twitch fibers contract gently and can keep working for hours. [6] They are packed with mitochondria and rely on a steady supply of oxygen, which gives them a dark red color and makes them tire slowly. [7] A marathon runner leans on these fibers for the long, steady effort.

    [8] Fast-twitch fibers behave in nearly the opposite way. [9] They contract with great force and speed but use up their energy quickly, so they tire within a minute or two. [10] These fibers burn stored sugar without waiting for oxygen to arrive, which produces power quickly but also produces waste that builds up in the muscle. [11] A sprinter, a weightlifter and a basketball player rising for a rebound depend on them for sudden power.

    [12] Most muscles contain a mixture of both types, and the proportions differ from person to person. [13] Training can improve the endurance of fast-twitch fibers, but the balance a person is born with sets limits on how far training can shift it. [14] That helps explain why athletes who excel at distance events often differ from athletes who excel at sprinting.

12. 8.

    Ren labels the link between paragraph 2 and paragraph 3. Which choice gives the right label and the right reason?

    • Unlike: in paragraph 2 slow-twitch fibers contract gently and keep working for hours, but in paragraph 3 fast-twitch fibers contract with great force and tire within a minute or two.
    • Unlike: in paragraph 2 the article says slow-twitch fibers keep working for hours, but in paragraph 3 it says fast-twitch fibers are the ones that matter most to an athlete.
    • Unlike: in paragraph 1 the article says each fiber is a single cell controlled by one nerve ending, but in paragraph 4 it says most muscles hold a mixture of both types of fiber.
    • Like: in paragraph 2 the article says slow-twitch fibers contract gently and keep working for hours, and in paragraph 3 it says fast-twitch fibers do the same and also keep working for hours.
13. 9.

    Tala asks what the contrast between the two kinds of fiber helps a reader understand about athletes.

    • Why a marathon runner and a sprinter, who need very different kinds of effort, can depend on different mixes of fibers.
    • Why a marathon runner can keep a steady pace for hours because of the dark red color of slow-twitch fibers that carry plenty of oxygen.
    • Why any athlete can become a sprinter by training the right fibers for long enough.
    • Why athletes must train hard and eat well in order to improve their results in a sport.
14. 10.

    Zee asks which kind of fiber the article says a weightlifter depends on. Which choice names it and gives the reason?

    • Fast-twitch, because it contracts with great force and speed even though it tires within a minute or two.
    • Fast-twitch, because it does not tire, so it can lift heavy loads for hours without a rest.
    • Fast-twitch, because it relies on a steady supply of oxygen and tires slowly during the effort.
    • Slow-twitch, because it contracts gently, can keep working for hours and is packed with mitochondria that supply energy.