Explain a complex idea in an essay
Grade 9 Reading Worksheet
Circle the best answer.
Read this first
Heat and Temperature Are Not the Same (informative draft)
[1] A cup of boiling water is much hotter than a bathtub of warm water, yet the bathtub could melt far more ice, and that puzzle shows that heat and temperature are two different things. [2] Both ideas describe the motion of particles, the atoms and molecules that make up matter, which keep moving even inside a solid.
[3] Temperature measures how fast, on average, the particles in a substance are moving. [4] In the boiling water, the particles move faster on average than the particles in the bathtub, so the cup has the higher temperature. [5] A thermometer reads this average, and it gives the same reading for a spoonful of the water as for the whole pot.
[6] Next, there is heat. [7] Heat is energy that moves from a warmer object to a cooler one because of the difference in their temperatures, and it keeps moving until the two are equally warm. [8] The total energy that a substance can give off in this way depends on how much of the substance there is, not just on how fast its particles move. [9] The bathtub holds thousands of times more water than the cup, so its many slower particles together store far more energy than the cup's few fast ones.
[10] Heat and temperature are basically the same thing, just measured in different ways. [11] This difference matters in a kitchen, where a large pot of soup stays warm long after a small cup of tea has cooled. [12] It also explains why a lake warms and cools more slowly than the air above it, since the lake must gain or lose an enormous amount of energy to change by even one degree. [13] Weather reports give the temperature of the air, but engineers who design heating systems must also work out how much heat a building gains or loses.
Ari sees that sentence [10] blurs the essay's two ideas. Which sentence states the difference between heat and temperature that the essay needs?
- Heat and temperature both describe moving particles, so the object with the higher temperature is the one holding more heat.
- Temperature measures how fast a substance's particles move on average, while heat is energy that flows from warmer to cooler and depends on how much substance there is.
- Heat measures how fast a substance's particles move on average, while temperature is energy that flows from warmer to cooler and depends on the amount.
- Heat and temperature both come from the motion of particles, the atoms and molecules that keep moving inside water, metal and air.
Sentence [6] opens paragraph 3 with no real link. Which sentence would link paragraph 3 to paragraph 2 for Bo?
- For example, heat is the energy that flows from a warmer object to a cooler one until both of them reach the same temperature.
- Temperature tells how fast particles move, but heat, the energy that flows between objects, also depends on how many particles there are.
- Next, this essay turns to heat, the energy that flows from a warmer object to a cooler one until both are the same temperature.
- Temperature depends on how many particles there are, but heat, the energy that flows between objects, tells just how fast they move.
Echoes and Reverberation (informative draft)
[1] A shout across a wide canyon can come back a moment later, clear enough to be heard as a second, fainter shout. [2] A shout inside a tiled bathroom also bounces off the walls, yet no separate copy is heard; instead, the sound seems to swell and linger. [3] Both effects come from sound waves reflecting off hard surfaces, but the way the reflections reach the ear makes them two different things, an echo and reverberation.
[4] Sound travels through air at about 343 meters per second, which is roughly one kilometer in three seconds. [5] The human ear can hear two sounds as separate only if they arrive about a tenth of a second apart or more. [6] A sound must therefore travel to a surface at least about 17 meters away and back again for its reflection to be heard as an echo.
[7] There is also reverberation to talk about. [8] In a small room, the walls are only a few meters away, so the reflections return almost at once and pile on top of the original sound. [9] Each sound bounces many times, off the floor, the ceiling and the walls, before it fades, and the overlapping reflections blend into one long sound. [10] This is why singing in a shower sounds fuller than singing in a carpeted bedroom, where soft surfaces absorb the sound instead of reflecting it.
[11] An echo is just a big reverberation that happens outdoors. [12] Concert hall designers use this difference with care, adding hard surfaces for a rich, lingering sound but shaping and covering others so that no distinct echo bounces back from the far wall. [13] Bats and ships use echoes for yet another purpose, sending out sounds and timing how long the reflections take to return in order to measure distance.
Jun sees that sentence [11] mixes up the two effects. Which sentence states the difference between an echo and reverberation that the essay needs?
- An echo is a reflection that arrives late enough to be heard on its own, while reverberation is many quick reflections blending into one longer sound.
- An echo and reverberation are both reflected sound, so they are really the same effect, heard in a large place or a small one.
- Reverberation is a reflection that arrives late enough to be heard on its own, while an echo is many quick reflections blending into one single sound that cannot be told apart.
- An echo and reverberation both happen when sound waves strike a hard surface, such as a canyon wall or a tiled floor, and bounce back.
Kira sees that sentence [7] opens paragraph 3 with no real link. Which sentence would link paragraph 3 to paragraph 2?
- Next, this essay will describe reverberation, the second effect that happens when sound reflects off a hard surface.
- Reverberation in a room makes reflections return too quickly to be heard on their own, so nearby walls produce no echoes in the room.
- Reflections from nearby walls return too quickly to be heard on their own, so instead of echoes they produce reverberation.
- In the same way, reflections from the nearby walls of a small room arrive late and are heard as separate echoes too.
Luz adds a heading above each paragraph. Which heading fits paragraph 3?
- The World of Sound and Hearing
- Reflections That Blend Together
- Singing in the Shower
- Why an Echo Needs Distance
Seeds and Spores (informative draft)
[1] Ferns and mosses cover forest floors and old stone walls, yet they never produce a single seed, and they spread by means of spores instead. [2] Seeds and spores both let a plant start new plants in new places, but they are built very differently, and the differences explain where each kind of plant can grow.
[3] A seed is a package with three main parts: a tiny young plant called an embryo, a supply of stored food, and a protective coat. [4] Because the embryo already has the beginnings of a root and a shoot, a seed can stay inactive for months or even years and then sprout when water and warmth reach it. [5] The stored food feeds the young plant until its first leaves open and it can make its own food from sunlight.
[6] Another thing is spores. [7] A spore is usually a single cell, so small and light that thousands of them can drift on the wind like dust. [8] It carries almost no stored food, so it can grow only if it lands somewhere damp and shaded that will support it right away. [9] In a fern, a spore does not grow straight into a fern; first it becomes a tiny, flat, heart-shaped plant that needs a film of water before the next stage can begin.
[10] Seeds and spores are both just tiny pieces that a plant drops so that a new one can grow. [11] This difference helps explain why ferns and mosses usually grow in damp places, while seed plants have spread across dry plains and even deserts. [12] A seed's coat and food supply let it wait out a dry season, but a spore depends on finding the right conditions almost at once. [13] Gardeners notice the same difference when they plant bean seeds in a pot of soil but must keep a tray of fern spores covered and moist for weeks.
Milo sees that sentence [10] treats seeds and spores as one thing. Which sentence states the difference the essay needs?
- Seeds and spores both let a plant start new plants in new places, and both can be carried a long way from the parent plant.
- A seed holds a young plant with its own food and coat, while a spore is usually a single cell with almost no food stored inside.
- A spore holds a young plant with its own food and coat, while a seed is usually a single cell with almost no food stored inside.
- Seeds and spores are both small parts that a plant releases, so each one is simply a different-sized version of the other.
Sentence [6] opens paragraph 3 with no real link. Which sentence would link paragraph 3 to paragraph 2 for Noah?
- For example, a spore is one kind of seed, a smaller kind that ferns and mosses make in place of a larger one.
- Unlike a seed, a spore carries no young plant and almost no food, and that changes where it can survive.
- Unlike a spore, a seed carries no young plant and almost no food, and that changes where it can survive.
- Next comes the second way that plants start new plants, which is the spore that ferns and mosses make.
Pia adds a heading above each paragraph. Which heading fits paragraph 2?
- A Single Cell on the Wind
- What a Seed Carries Inside
- Waiting for Months or Years
- How Plants Live and Grow
What Makes Glass Different from a Crystal (informative draft)
[1] A window pane and a clear quartz crystal can look almost alike, and both are made mostly of the same substance, silica, which is also the main ingredient in most sand. [2] Inside, however, their atoms are arranged in different ways, and that difference explains how glass is made and why it behaves as it does.
[3] In a quartz crystal, the atoms of silicon and oxygen are locked into a neat, repeating pattern, like rows of tiles on a kitchen floor. [4] Because of this order, crystals grow with flat faces and sharp edges, and a crystal melts at one exact temperature.
[5] Another thing is how glass gets made. [6] Workers melt sand together with soda ash and limestone in a furnace hotter than 1,400 degrees Celsius, and the soda ash lowers the temperature at which the sand melts. [7] The melted glass is then cooled quickly enough that its atoms have no time to line up, so they are frozen in the jumbled arrangement they had as a liquid. [8] A solid with this disordered inner structure is called amorphous, a word that means "without shape." [9] Glass does not melt at one sharp temperature; instead, it softens slowly as it is heated, which is why a glassblower can bend and stretch it.
[10] Glass and crystals are pretty much the same, since they're both hard, clear solids. [11] People sometimes say that glass is a very slow liquid, pointing to old windows in centuries-old buildings that are thicker at the bottom. [12] In fact, those panes were made unevenly by older methods, and glass at room temperature does not flow by any amount that could be measured over centuries. [13] Its disordered structure is what makes glass so useful, since it can be shaped into bottles, lenses and windows while it is soft and then sets hard and clear.
Ren sees that sentence [10] says glass and crystals are the same. Which sentence states the difference the essay needs?
- Glass and quartz are both made of silica, but glass has its atoms in a repeating pattern, while quartz keeps the jumbled arrangement of a liquid.
- Glass and quartz are both made of silica, but quartz has its atoms in a repeating pattern, while glass keeps the jumbled arrangement of a liquid.
- Glass and quartz are both hard, clear solids made of silica, so glass is simply a crystal that people make in a factory.
- Glass and quartz are both hard, clear solids, and both are made mostly of silica, the substance that is found in most sand.
Tala sees that sentence [5] opens paragraph 3 with no real link. Which sentence would link paragraph 3 to paragraph 2?
- Quartz, by contrast, is made in a way that keeps its atoms from ever forming an orderly pattern.
- Next, this essay explains the steps that workers follow when they make glass out of sand in a furnace.
- For example, glass is one kind of crystal, made when sand is melted and its atoms are packed into neat, orderly rows.
- Glass, by contrast, is made in a way that keeps its atoms from ever forming that orderly pattern.
