Lesson plan Grade 7 English Language Arts
Ledbury's Water Tower: Explanatory Writing on Pressure
A grade 7 ELA lesson where students study how a water tower creates steady pressure, then write an explanatory paragraph using cause-and-effect transitions.
Objectives
- Students will explain in writing how a water tower uses height and gravity to create steady water pressure.
- Students will organize an explanatory paragraph with a clear topic sentence and cause-and-effect transitions.
Vocabulary
- Water tower
- A water tower is a big tank raised high above town that stores drinking water. Its height is what pushes water through the pipes, keeping the pressure steady even when the power goes out.
Also: gravity, pressure, cause and effect, transition
Teacher overview
The fictional town of Ledbury keeps a water tower on its highest hill, and the height of the water inside the tank is the reason every faucet in town runs with steady pressure. This lesson gives seventh graders a concrete science topic to explain in writing, so the explanatory skills they practice attach to a real process rather than an abstract prompt. A common misconception worth naming out loud is that a pump inside the house or under the street is what pushes water out of the tap. In a gravity system the stored height does most of that work, and the writing task asks students to explain that cause clearly.
Procedure
Hook (5 min): Project a simple side-view sketch of a water tower on a hill with houses below it. Ask students to write one sentence predicting why the town built the tank up high instead of at ground level. Take two or three predictions without confirming them.
Build the explanation (12 min): Walk through the cause chain the students will later write about. Water sits high inside the tank. Gravity pulls down on that column of water, and the weight of the column creates pressure at every point below it. The taller the column of water above a house, the greater the pressure at that house. Note the real service range operators aim for: in the town of Ledbury, as in most systems, crews try to keep pressure between 40 and 80 psi at the tap and never below the 20 psi that regulations set as a floor. Explain that the tower also stores water for busy mornings and firefighting, so pressure stays even when demand jumps.
Model the paragraph (10 min): Display a short explanatory paragraph frame with three moves: a topic sentence that states the main idea, two or three sentences that explain the cause chain in order, and a closing sentence. Think aloud as you draft the topic sentence and the first cause sentence, showing where a transition such as "because," "as a result," or "which means" links a cause to its effect. Underline each transition as you use it.
Guided writing (13 min): Students draft their own explanatory paragraph answering the question, "How does Ledbury's water tower create steady pressure for the houses below it?" Circulate and prompt students who stall to name the next cause in the chain before writing the next sentence.
Independent revision (8 min): Students reread their draft and add or strengthen at least one cause-and-effect transition, then check that their topic sentence names the main idea rather than a small detail.
Exit ticket (2 min): On an index card, each student underlines one cause-and-effect transition in their paragraph and writes the cause and the effect it connects. Collect the cards and scan for whether students linked a real cause to a real effect; use a quick thumbs-up or thumbs-down poll to gauge who still needs support before the next class.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Differentiation
Support
Provide a partially completed paragraph frame with the topic sentence supplied and blanks for the two cause sentences, plus a short word bank of transitions ("because," "as a result," "so," "which means"). Let these students explain the cause chain aloud to a partner before they write.
Extension
Ask students to add a second paragraph explaining what happens to pressure for a house far downhill from the tank, and why an operator might install a pressure-reducing valve there. The paragraph should keep the same topic-sentence-and-transitions structure.
ELL supports
Pre-teach "gravity," "pressure," "column," and "transition" with the labeled tower sketch, and pair each term with a simple gesture or picture. Provide sentence starters ("The water tower creates pressure because ___. As a result, ___.") so students can focus on the science idea while the sentence shape is supplied.
Extensions
Invite students to find their own town's water tower or standpipe on a map or in a photo and describe, in one explanatory paragraph, how its height serves the neighborhood around it. A short letter to the local public works department asking how tall the tank is and what pressure a nearby school receives turns the lesson into authentic local research.