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Classroom activity Grade 5 English Language Arts

Word Detectives at the Ravendale Bay Salt Plant

A grade 5 station rotation where teams use context clues to define four desalination words and quote the sentence in each station card that gave the clue.

Objectives

  1. Students will use context clues to define an unfamiliar word from an informational card.
  2. Students will quote the exact sentence that supports their definition.
  3. Students will explain how a desalination plant turns seawater into drinking water.

Vocabulary

Brine
The extra-salty water left over after desalination pulls fresh water out of seawater. Plants must dispose of it carefully so it does not harm sea life.
Desalination
Turning salty water, like ocean water, into fresh water people can use. It works, but it takes a lot of energy and leaves behind very salty water that must be handled carefully.

Also: intake, membrane, blend

Teacher overview

This is a four-station rotation for teams of three or four students, and each station teaches one step of turning seawater into drinking water. Each station card carries a target word with no glossary and no dictionary beside it, so students have to work the meaning out of the surrounding sentences and then point to the sentence that gave it to them. The stations are posted in plant order, which means a team that works its way around the room in sequence follows the same path the water takes through the plant. The rotation ends with a debrief that lines up the four words into one explanation of the process.

Activity Directions

  1. Setup (5 minutes of prep before class, not part of the 40 minutes). Print the four station cards from the handout and post them around the room in order: Station 1 near the door, then Stations 2, 3, and 4 clockwise. Place four or five copies of the student handout at each station. Explain that the stations are posted in the order the water moves through the plant.
  2. Launch (5 min). Tell students that each card carries one word they may not know and that no definition is set apart for them anywhere on the card. Their job is to work out the meaning from the sentences around the word, then copy the one sentence that gave them the clue. Model the method with the word "gauge" in a sentence you write on the board.
  3. Form teams and assign a start (2 min). Group students in threes or fours. Send one team to each station. With more than four teams, double up at stations and have the pairs of teams work quietly on opposite sides of the card.
  4. Rotate (28 min). Give teams seven minutes at each station. At each stop, the team reads the card aloud once, then each student writes the two answers for that station on the handout individually. Call the rotation at seven minutes and have teams move to the next station clockwise.
  5. Sort the words (3 min). After the last rotation, ask each team to write the four target words in plant order on the back of one handout. Post the correct order on the board and have teams check their own.
  6. Debrief (2 min). Ask two questions aloud. First: which station's word was hardest to work out, and what in the card finally gave it away? Second: the plant sends brine back to the bay, yet no one part of the bay stays extra salty. What does the Station 3 card say that explains why? Take two or three answers for each before dismissing.
Word Detectives at the Ravendale Bay Salt Plant — Grade 5 English Language Arts
Name: ____________________________ Date: ______________

Student Handout

Word detectives: the Ravendale Bay salt plant

Ravendale is a fictional coastal town. It sits where the rivers run dry in summer, so the town built a plant that makes drinking water out of seawater. That process is called desalination. Visit each station in order. Read the card. Then answer the two questions for that station.

Station 1 card

The plant begins at the water's edge. A long pipe reaches out under the bay, and seawater is drawn in through it. Workers call this pipe the intake. A screen across the mouth of the intake keeps fish and seaweed out of the plant. Divers check the screen twice a month.

Station 2 card

Next, pumps push the seawater hard against a membrane. A membrane is what stops the salt. Fresh water squeezes through its tiny holes, and the salt cannot follow. It takes a great deal of pressure to force water through, which is why the pumps are the loudest machines in the building.

Station 3 card

The salt that stays behind does not disappear. It leaves the membranes in a smaller stream of very salty water called brine. Brine is about twice as salty as the bay. The plant sends it back to the bay through a pipe that spreads it out in the current, so it mixes quickly and no one spot stays salty for long.

Station 4 card

The fresh water from the membranes is too pure to send out alone, and it would taste flat. Workers blend it with treated water from the town's old well before it goes into the pipes. A blend is a mix. The largest plant of this kind in the United States is in Carlsbad, California, which makes about 50 million gallons of fresh water a day, roughly a tenth of what San Diego County uses.

Questions

  1. What does the word "intake" mean in Station 1?
  2. Copy the exact sentence from Station 1 that helped you work out the meaning of "intake."
  3. What does the word "membrane" mean in Station 2?
  4. Copy the exact sentence from Station 2 that helped you work out the meaning of "membrane."
  5. What does the word "brine" mean in Station 3?
  6. Copy the exact sentence from Station 3 that helped you work out the meaning of "brine."
  7. What does the word "blend" mean in Station 4?
  8. Copy the exact sentence from Station 4 that helped you work out the meaning of "blend."

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: The pipe that draws seawater into the plant. Accept "the pipe that brings water in" or any wording that names a pipe and the drawing in of water.
  2. Answer: "A long pipe reaches out under the bay, and seawater is drawn in through it." Accept also "Workers call this pipe the intake." Both sentences carry the clue.
  3. Answer: A barrier with tiny holes that lets fresh water through and holds the salt back.
    Accept "a filter that stops salt."
  4. Answer: "Fresh water squeezes through its tiny holes, and the salt cannot follow." Accept also "A membrane is what stops the salt."
  5. Answer: Very salty water left behind after the fresh water is removed. Accept "leftover salty water."
  6. Answer: "It leaves the membranes in a smaller stream of very salty water called brine."
    Accept also "Brine is about twice as salty as the bay."
  7. Answer: A mix of two kinds of water. Accept "mixing the pure water with well water."
  8. Answer: "Workers blend it with treated water from the town's old well before it goes into the pipes." Accept also "A blend is a mix."

Differentiation

Support

Give these students a handout with the four target words already listed beside three answer choices each, so the station task becomes choosing and then justifying with the quoted sentence. Pair them with a strong reader who reads the card aloud at each stop.

Extension

Ask these students to write a fifth station card describing what the plant does when a storm packs the intake screen with seaweed, using at least two words from the rotation and one new word a reader could only work out from the sentences around it.

ELL supports

Pre-teach "salt," "pipe," "pump," and "mix" with objects and gestures. Set a jar of plain water beside a jar of water stirred with salt, without tasting either, so students can see that salty water and fresh water look the same. Provide a definition frame: "I think ___ means ___ because the card says ___."

Extensions

Teams use their four definitions to write a six-sentence explanation of how the Ravendale Bay plant turns seawater into tap water, in plant order, using each target word once and underlining it.