Lesson plan Grade 6 English Language Arts
Sallowbeck Creek's Fish Kill: A Grade 6 Cause and Effect Lesson
A grade 6 ELA lesson in which students trace the cause and effect chain in a fictional creek's fish kill report and write an explanatory paragraph from it.
Objectives
- Students will trace a cause and effect chain across a short informational report and put its links in order.
- Students will cite the specific sentence or table reading that supports each link in the chain.
- Students will write an explanatory paragraph that uses cause and effect transitions to connect the links.
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.
Also: decompose, algae, cause, effect, transition
Teacher overview
Sixth graders can usually name a cause and an effect in isolation, yet they lose the thread when a report links four or five of them in sequence. This lesson gives them a short field report from the fictional Tullymore Water District about dead fish in Sallowbeck Creek, and asks them to rebuild the chain that runs from a rainstorm to the fish. The misconception worth addressing directly is the common student assumption that fish in a creek die because something poisonous was dumped in the water. In this scenario nothing toxic entered the creek at all, since the fish ran out of dissolved oxygen after warm water and decomposing algae drove the oxygen level down.
Procedure
Hook (5 min): Write one sentence on the board: "The fish in the creek died because someone poured something into it." Ask students to signal thumbs up or thumbs down for whether they believe that is the only way fish die in a creek. Record the count without comment and tell students the report they are about to read explains a different path.
Reading and annotation (10 min): Distribute the handout. Students read the Tullymore Water District report once for gist, then reread it with a pencil, underlining every sentence that states a cause and circling every sentence that states a result. Remind them that the table counts as part of the report, so a reading in the table may be the evidence for a link.
Modeling the chain (10 min): On chart paper, model the first two links aloud. Write "heavy rain on July 3" in the first box, draw an arrow, and write "fertilizer washed into the creek" in the second, saying which sentence in the report supports each. Then think aloud about why the third box cannot be "the fish died," because several more links still sit between the fertilizer and the fish.
Guided practice (10 min): In pairs, students finish the chain on the back of the handout, adding boxes for the algae bloom, the algae dying, the decomposing algae using up oxygen, and the oxygen dropping below what the sunfish need. Each pair writes the supporting sentence or table reading under every box. Circulate and check that pairs are citing the report rather than guessing.
Formative check (3 min): Ask every student to hold up the number of fingers matching how many boxes their chain holds between the July 3 rain and the dead fish. The correct count is five: fertilizer in the creek, the algae mat, the mat dying back, bacteria using oxygen as they decompose it, and the oxygen falling below what sunfish need. If more than five students show a different number, rebuild the middle of the chain on the board with the class before moving on.
Independent writing (10 min): Students answer handout items 1 through 5 and then draft the paragraph in item 6, using at least two of the listed transitions and keeping the links in order.
Closure (2 min): Collect the handouts. Read one strong paragraph aloud without naming the writer, and ask the class to identify the two transitions that carried the reader from one link to the next.
Student Handout
Sallowbeck Creek Fish Report, prepared by the fictional Tullymore Water District
On the morning of July 12, a resident called our office about dead sunfish along the shallow bend of Sallowbeck Creek below Cooper Road. A technician collected readings that afternoon and returned twice more that month. Every number below is from our own testing in this fictional creek.
| Date | Water temperature (Fahrenheit) | Dissolved oxygen | Fish observed |
|---|---|---|---|
| June 14 | 68 degrees | 8.4 milligrams per liter | Healthy sunfish in the shallows |
| July 5 | 79 degrees | 6.1 milligrams per liter | Healthy sunfish in the shallows |
| July 12 | 86 degrees | 3.2 milligrams per liter | Dead sunfish along the bend |
| July 26 | 74 degrees | 6.8 milligrams per liter | A few healthy sunfish |
Dissolved oxygen is the oxygen mixed into the water itself, and fish pull it across their gills to breathe. Most fish need dissolved oxygen above 5 milligrams per liter. Warm water holds less oxygen than cool water, so a hot week lowers the supply even when nothing else changes.
Two other things happened this July. A heavy rain on July 3 washed lawn fertilizer and runoff from a hay field into the creek. Fertilizer feeds algae, and the algae in the creek grew into a thick green mat within a few days. That mat died back by July 10. Bacteria then decomposed the dead algae, and those bacteria used dissolved oxygen from the water while they worked.
We found no oil, no chemical spill, and no damaged pipe anywhere upstream. Answer the questions below using only this report.
- On which date did the technician find dead sunfish in Sallowbeck Creek?
- What was the dissolved oxygen reading on the date the dead sunfish were found?
- The report says warm water holds less oxygen than cool water. Give one pair of table rows that shows this pattern, and name the temperature and the oxygen reading in each row.
- What made the algae in the creek grow so quickly in early July? Copy the sentence from the report that tells you.
- Explain how the dying algae lowered the oxygen in the creek. Use the words "decompose" and "oxygen" in your answer.
- Write one paragraph explaining why the sunfish died. Put the causes in the order they happened, from the rain to the fish, and use at least two of these transitions: "because," "as a result," "which led to," "finally."
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
- Answer: July 12. The table lists dead sunfish along the bend only in the July 12 row, and the report says the resident called that morning.
- Answer: 3.2 milligrams per liter. This is the dissolved oxygen reading in the July 12 row, below the level the report says most fish need.
- Answer: June 14 and July 12. Accept any pair in which the warmer row has the lower oxygen reading, such as June 14 at 68 degrees with 8.4 milligrams per liter compared with July 12 at 86 degrees with 3.2 milligrams per liter.
- Answer: Fertilizer washed into the creek fed the algae. Students should copy the sentence about the July 3 rain washing lawn fertilizer and hay field runoff into the creek, or the sentence stating that fertilizer feeds algae.
- Answer: Bacteria decomposed the dead algae and used dissolved oxygen while they did it. The more algae there was to decompose, the more oxygen left the water, which is why the July 12 reading fell so far below the earlier readings.
- Answer: Answers will vary. A proficient paragraph keeps the links in this order: the July 3 rain washed fertilizer into the creek, the fertilizer fed a thick algae mat, the mat died back by July 10, bacteria decomposing it used up dissolved oxygen, the hot week left less oxygen in the warm water to begin with, and the reading fell to 3.2 milligrams per liter, below what sunfish need. Look for at least two of the listed transitions and for no missing link between the rain and the fish.
Differentiation
Support
Give these students the chain boxes already drawn and labeled but out of order, so their task is sequencing rather than generating. For item 6, provide the paragraph frame: "The fish in Sallowbeck Creek died because ___. First, ___. As a result, ___. Finally, ___."
Extension
Ask students to write a second short paragraph explaining why the July 26 readings improved, using the same transition words and citing the temperature and oxygen readings from that row. Then have them name one measurement the district could add to its testing that would make the chain easier to prove.
ELL supports
Pre-teach "dissolved oxygen," "decompose," "algae," and "runoff" with a labeled sketch of a creek showing rain, a green mat, and fish below the surface. Allow students to answer items 1 through 4 with short phrases or by pointing to the table row, and provide the transitions on a word bank card with a sample sentence for each.
Extensions
Have students turn the finished paragraph into a two-sentence notice a water district could post at the creek access, then compare drafts and decide which version explains the cause most clearly to a reader who has never heard of dissolved oxygen.