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Worksheet Grade 7 English Language Arts

Inside the Stanwick Water Plant: Explanatory Writing

A grade 7 ELA worksheet where students order a treatment plant's steps and write an explanatory paragraph using sequence and cause-and-effect transitions.

Objectives

  1. Students will put the steps of drinking-water treatment in the correct order from a briefing.
  2. Students will write an explanatory paragraph using sequence and cause-and-effect transitions.

Vocabulary

Coagulation
Coagulation is the first cleaning step at a drinking water plant. Operators quickly mix in a chemical that makes tiny bits of dirt stop pushing each other away so they can start sticking together.
Sedimentation
Sedimentation is the step where water sits almost still in a big basin so the heavy clumps of dirt can sink to the bottom. The cleaner water on top then moves on to the filters.
Filtration
Filtration is the step where water passes through layers of sand, gravel, or other materials that trap the small particles still left in it. It works like a very fine strainer.
Disinfection
Disinfection is the step that kills or disables germs in water so it is safe to drink. Water plants usually disinfect with chlorine, ultraviolet light, or ozone.

Also: transition

Teacher overview

The fictional Stanwick Water Plant cleans river water in four main steps, and each step depends on the one before it, which makes treatment a natural subject for explanatory writing that uses sequence and cause-and-effect transitions. Students first put the steps in order, then draft a paragraph explaining how the plant turns cloudy river water into clean tap water. As a teacher reference, note that a conventional plant must keep finished water very clear, at or below 0.3 NTU in at least 95 percent of monthly samples, which is the standard the last steps work toward.

Inside the Stanwick Water Plant: Explanatory Writing — Grade 7 English Language Arts
Name: ____________________________ Date: ______________

Student Worksheet

Read the briefing, then complete the items.

Briefing: How the Stanwick Plant Cleans River Water

The Stanwick Water Plant pulls water from the Stanwick River, which often looks cloudy because it carries tiny bits of clay and dirt. The plant cleans the water in four main steps.

In coagulation, the plant adds a chemical that makes the tiny particles clump together into larger, heavier clumps. In sedimentation, the water sits in a large, calm basin so those heavy clumps sink to the bottom and can be removed. In filtration, the water passes down through layers of sand and gravel that trap the smaller particles still floating in it. In disinfection, the plant adds a small amount of chlorine to kill germs before the clean water flows out to homes.

The order matters. Filters would clog quickly if the plant tried to filter cloudy water before letting the heavy clumps settle out.

  1. Which step adds a chemical that makes tiny particles clump together?
  2. During which step do the heavy clumps sink to the bottom of a calm basin?
  3. What does the filtration step trap that the earlier steps left behind?
  4. Why does the plant add chlorine during disinfection?
  5. List the four steps in the correct order, from first to last.
  6. Write a topic sentence for a paragraph that explains how the Stanwick plant cleans river water.
  7. Write two sentences that each use a sequence transition (such as "first," "next," or "then") to explain two of the steps in order.
  8. Write one sentence that uses a cause-and-effect transition (such as "because" or "as a result") to explain why the steps must happen in that order.
  9. Using your answers to items 5 through 8, write a full explanatory paragraph that explains how the Stanwick plant cleans river water.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: Coagulation. The briefing says coagulation "adds a chemical that makes the tiny particles clump together."
  2. Answer: Sedimentation. The water "sits in a large, calm basin so those heavy clumps sink to the bottom."
  3. Answer: The smaller particles still floating in the water. Filtration passes water through sand and gravel that "trap the smaller particles still floating in it."
  4. Answer: To kill germs before the water reaches homes. The briefing says the plant adds chlorine "to kill germs before the clean water flows out to homes."
  5. Answer: Coagulation, sedimentation, filtration, disinfection. This is the order given in the briefing.
  6. Answer: Answers will vary. A strong topic sentence names the main idea, such as "The Stanwick Water Plant cleans river water in four steps that build on each other."
  7. Answer: Answers will vary but each sentence must use a sequence transition correctly, such as "First, the plant adds a chemical so the particles clump. Next, the water sits so the clumps settle."
  8. Answer: Answers will vary but must use a cause-and-effect transition, such as "The clumps must settle first because the filters would clog if the water were still cloudy."
  9. Answer: Answers will vary. A proficient paragraph opens with a topic sentence, explains the four steps in order with sequence transitions, uses at least one cause-and-effect transition, and closes the idea.

Differentiation

Support

Give these students the four step names on cards to physically arrange in order before writing, and supply a paragraph frame with the topic sentence provided and blanks for each step. Offer a transition word bank.

Extension

Ask students to explain, in two or three added sentences, what would go wrong if the plant swapped the order of filtration and sedimentation, using cause-and-effect transitions to make the reasoning clear.

ELL supports

Pre-teach the four step names with a simple labeled diagram showing cloudy water becoming clear. Allow students to answer items 1 through 4 with the step name alone, and provide sentence frames with the transition words already inserted for items 7 and 8.