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Worksheet Grade 6 English Language Arts

Thornapple Lake's Algae Bloom: A Grade 6 Vocabulary Worksheet

A grade 6 worksheet where students use context clues and cited evidence from a fictional lake's water-testing notebook to define nutrient-pollution vocabulary.

Objectives

  1. Students will use context clues to define technical vocabulary drawn from a water-testing report.
  2. Students will cite specific textual evidence to support their definitions and inferences.

Vocabulary

Dissolved oxygen
Dissolved oxygen is the oxygen gas mixed into water that fish and other underwater animals breathe. Cold, moving water holds more oxygen than warm, still water.
Turbidity
Turbidity is a measure of how cloudy or murky water looks because of tiny particles floating in it. Clear water has low turbidity, and muddy water has high turbidity.

Also: nutrient, phosphorus, algae bloom

Teacher overview

Thornapple Lake is a fictional lake used for this worksheet. A water-testing team's field notebook entry describes a sudden algae bloom and the technical vocabulary technicians use to record what they find. A common misconception among sixth graders is treating "algae bloom" as a synonym for "dirty water" rather than understanding it as a rapid growth of algae triggered by excess nutrients. This worksheet asks students to define five testing terms using context clues alone, then support each definition with an exact quotation from the notebook, practicing the same evidence-citing skill a real water-quality report requires of its readers.

Thornapple Lake's Algae Bloom: A Grade 6 Vocabulary Worksheet — Grade 6 English Language Arts
Name: ____________________________ Date: ______________

Student Worksheet

Thornapple Lake is a fictional lake used for this worksheet. Read the field notebook entry below, then answer the questions that follow.

Field notebook, Thornapple Lake:

"The water near the boat ramp looks bright green today. Students on the dock say it smells different than usual. Our nutrient readings show far more phosphorus and nitrate than in past summers. This extra nutrient load is likely washing in from lawns upstream after last week's rain. That nutrient load is feeding an algae bloom across the north end of the lake. Dissolved oxygen in that area has dropped to 3 mg/L. Most fish need at least 5 mg/L to survive. Turbidity is also higher; the water looks cloudier than it did in June. We are treating this as a warning sign, not a crisis, because the bloom has not spread past the swimming buoys yet."

  1. Using context clues from the notebook, write your own definition of "nutrient."
  2. What specific phrase in the notebook helped you figure out what an "algae bloom" is? Quote it.
  3. Based on context, what do you think "dissolved oxygen" means? Explain the clue that led you there.
  4. Quote the exact sentence that explains why dissolved oxygen matters to fish.
  5. What do "phosphorus" and "nitrate" have in common as the notebook uses them? Cite the sentence that groups them together.
  6. The technician says turbidity is "also higher." Using context, explain what turbidity means and quote the clue that supports your answer.
  7. Quote the sentence that states the lake's actual dissolved-oxygen reading.
  8. The notebook calls the situation a "warning sign," not a "crisis." What detail in the text explains that choice of words? Cite it.
  9. If a different lake had very low nutrient levels, would you expect an algae bloom there? Use evidence to explain.
  10. Write one original sentence that correctly uses the word "nutrient" in a new context, such as a garden or a farm field.

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: A nutrient is a substance in water, such as phosphorus or nitrate, that helps living things like algae grow. Students should reference that "nutrient readings" of phosphorus and nitrate are linked directly to the algae bloom described two sentences later.
  2. Answer: "That nutrient load is feeding an algae bloom across the north end of the lake." This phrase directly connects the extra nutrients to the growth of algae.
  3. Answer: Dissolved oxygen is oxygen present in the water itself. The clue is that its level is stated in mg/L and the notebook says most fish "need at least 5 mg/L to survive," showing it is a measurable substance in the water that supports life.
  4. Answer: "Most fish need at least 5 mg/L to survive."
  5. Answer: Both are nutrients; the notebook groups them together as the extra nutrient load washing in from lawns upstream. Students should cite: "Our nutrient readings show far more phosphorus and nitrate than in past summers."
  6. Answer: Turbidity means how cloudy or unclear the water looks. The supporting clue is "the water looks cloudier than it did in June."
  7. Answer: "Dissolved oxygen in that area has dropped to 3 mg/L."
  8. Answer: The technician notes that "the bloom has not spread past the swimming buoys yet," meaning the problem is still contained rather than affecting the whole lake, which is why the notebook treats it as a warning rather than an emergency.
  9. Answer: No, a lake with very low nutrient levels would be unlikely to have an algae bloom, because the notebook shows the bloom at Thornapple Lake was caused specifically by extra phosphorus and nitrate feeding the algae's growth.
  10. Answer: Answers will vary. Accept any grammatically correct sentence that uses "nutrient" to mean a substance that helps a living thing grow, such as a sentence about fertilizer providing nutrients to garden plants.

Differentiation

Support (below grade level)

Provide a vocabulary bank with the five key terms and a one-line hint for each (for example, "dissolved oxygen: oxygen ___ in the water") so students confirm rather than construct definitions from scratch. Allow students to underline the supporting sentence directly in the notebook text instead of copying it out by hand for items 4 and 7.

Extension (above grade level)

Ask students to rewrite the field notebook entry from the point of view of a resident swimming at the lake who does not know any of the technical vocabulary, translating each term into plain language while keeping the same sequence of events.

ELL supports

Preview the five vocabulary words with simple picture cards, such as a green pond for "algae bloom" and a cloudy glass of water for "turbidity," before students read the notebook entry. Allow items 1, 3, and 6 to be answered orally or with a labeled sketch instead of a full written definition.