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Reading passage Grade 6 English Language Arts

Sparrow Pond's pH Swing: A Grade 6 Aquatic Chemistry Reading Passage

A grade 6 informational passage following a class's weekly pH testing at a fictional pond, tracing how a storm shifts pH and a natural buffer restores it.

Objectives

  1. Students will identify how pH testing data support a claim about pond health.
  2. Students will make an inference about why a stable pH matters for aquatic life.

Vocabulary

pH
pH is a number that tells whether water is acidic, like lemon juice, or basic, like baking soda mixed in water. Pure water sits in the middle of the scale at a pH of 7.

Also: acidic, basic, aquatic, buffer

Teacher overview

Sparrow Pond is a fictional pond that a class monitors each week using a simple water-testing kit. This passage follows the class's pH readings over several months, showing how a rainstorm can temporarily shift a pond's chemistry and how the pond's natural minerals help it recover. A common misconception among sixth graders is that "acidic" and "basic" describe pollution and cleanliness rather than points on a chemical scale; the passage keeps the vocabulary tied to the actual pH scale throughout to correct that idea.

Sparrow Pond's pH Swing: A Grade 6 Aquatic Chemistry Reading Passage — Grade 6 English Language Arts
Name: ____________________________ Date: ______________

Passage

Every pond, lake, and river has a chemical property called pH. This number tells scientists how acidic or basic the water is. The pH scale runs from 0 to 14. A pH below 7 is called acidic. A pH of exactly 7 is called neutral. A pH above 7 is called basic. Most freshwater ponds sit near the middle of this scale. Small changes matter more than people might expect. Many fish, insects, and plants can only survive within a narrow pH range.

Sparrow Pond is a fictional site used for this passage. A class of sixth graders tests its water every Friday afternoon. They use a simple color-changing test strip. For the first six weeks of school, their readings stayed steady. Each reading landed between 7.0 and 7.4. The students recorded each number in a shared notebook. The readings barely moved from week to week, even though the weather kept changing.

That steady pattern broke after a heavy rainstorm in October. The next Friday's test produced a reading of 6.2. That was far more acidic than any earlier result. Some students worried the pond had been polluted overnight. Their teacher explained a different reason. Rain itself is naturally a little acidic. A large storm can wash acidic runoff from soil and leaves into a pond. This runoff can lower a pond's pH for a short time, before the water settles.

The following week's test told the rest of the story. The reading had climbed back to 6.9. By the third week after the storm, it had returned to 7.1. That was close to where it had started. The teacher introduced a new word to explain the recovery: buffer. A buffer is a substance that resists sudden changes in pH. Limestone in soil or rock is one common buffer. It neutralizes extra acid. Sparrow Pond sits over a bed of limestone. That limestone acted as a buffer. It pulled the pond's chemistry back toward its usual range within a few weeks.

The class's pond testing connects to a larger system. Sparrow Pond drains into the reservoir that supplies the town's drinking water. The utility that treats that water also watches pH. It aims to keep the drinking water it delivers in a stable range, generally between 6.5 and 8.5. Pond chemistry also affects the animals living in the water. Most fish need dissolved oxygen above 5 mg/L to survive. A sharp drop in pH can also make it harder for fish to take in oxygen through their gills. This is one reason a sudden chemical swing worries scientists, even one that corrects itself within a few weeks.

By the end of the unit, the class had built a data table spanning four months. Only one unusual reading stood out from a long, steady pattern. Their teacher pointed out something important. That one outlier told a more interesting story than a table of identical numbers would have. It showed the pond responding to a real event. Then it showed the pond recovering on its own. That is evidence a healthy watershed is working the way it should. A single rainstorm can change a pond's chemistry within a day, while a healthy pond can turn that change back within a few weeks.

Questions

  1. What is pH, according to the passage?
  2. What happened to the class's pH readings during the first six weeks of testing?
  3. What event caused the pH reading to drop to a more acidic level in October?
  4. According to the passage, what is a buffer, and what role did limestone play at Sparrow Pond?
  5. Why might a sudden pH change worry scientists, even if the pond recovers within a few weeks? Use details from the passage.
  6. How does Sparrow Pond's water connect to the town's drinking water supply, based on the passage?
  7. The passage says the one outlier reading "told a more interesting story than a table of identical numbers would have." What do you think the teacher meant? Use evidence from the passage.
  8. Based on the passage, why do you think the class recorded pH readings every week instead of testing only once?

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: pH is a number that tells how acidic or basic water is, measured on a scale from 0 to 14.
  2. Answer: The readings stayed steady, landing between 7.0 and 7.4 every week, showing little change despite changing weather.
  3. Answer: A heavy October rainstorm washed acidic runoff from soil and leaves into the pond, temporarily lowering its pH.
  4. Answer: A buffer is a substance, such as limestone, that resists sudden changes in pH; the limestone bed under Sparrow Pond neutralized the extra acid and helped the pond's pH return to its usual range.
  5. Answer: Answers will vary but should reference that fish need enough dissolved oxygen and that a sudden pH change can make it harder for them to take in oxygen, so even a temporary chemical swing could stress the animals living there before the pond recovers.
  6. Answer: Sparrow Pond drains into the reservoir that supplies the town's drinking water, and the utility that treats that water also watches pH, aiming to keep the drinking water it delivers between 6.5 and 8.5.
  7. Answer: Answers will vary but should reference that the one unusual reading showed the pond actually responding to and recovering from a real event, which demonstrates the ecosystem working as expected, while a table of identical numbers would not have shown that process at all.
  8. Answer: Answers will vary but should reference that testing weekly let the class catch and track a change over time, such as the October storm's effect and the pond's gradual recovery, which a single test could not have shown.

Differentiation

Support (below grade level)

Provide a simple number line from 0 to 14 with "acidic," "neutral," and "basic" labeled at the correct points, and allow students to answer items 1 and 2 by pointing to values on the number line or underlining the passage sentence that gives the answer instead of writing full sentences.

Extension (above grade level)

Ask students to research, using only the passage and teacher-provided facts and not outside sources, what other natural buffers besides limestone might protect a pond's pH, and explain how they would test their idea using the same weekly testing method Sparrow Pond's class used.

ELL supports

Pre-teach "acidic," "basic," "neutral," and "buffer" with a simple visual, such as a number line with a lemon at the acidic end, a bar of soap at the basic end, and plain water at the neutral middle, before reading. Allow students to answer literal questions 1, 2, and 3 with short phrases rather than full sentences.