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Grade 7 · Science · 30 minutes

Unit 3 · Watersheds and Solutions · Lesson 1 of 2

Where Does the Rain Go?

Connect a runoff diagram, measurements and an environmental-impact proposal.

Mr. S Teaches · Original starter mini-lesson · MS7-SCI-05

Learning objective

Explain a runoff pathway and propose a measurable way to reduce water leaving a model site.

Before you begin

  • Understand infiltration and surface runoff.

Gather your materials

  • Paper or notebook
  • Pencil and the passage, model directions or data printed in this lesson

Language to know

watershed
An area draining toward a shared outlet.
impervious
Describing a surface that water does not readily pass through.
monitor
To measure a condition over time to track change.

Understand the concept

Site account: Rain falling on a model schoolyard can infiltrate soil or run toward a storm drain and creek. In equal 100 mL model-rain trials, pavement sends 85 mL to the outlet and planted soil sends 30 mL. The model holds slope and rainfall constant. A planted strip could increase infiltration, but an outdoor proposal must consider soil, rainfall intensity, maintenance and location. Runoff volume alone does not establish water quality or show how much pollution reaches the creek.

Teach it step by step

  1. Read the account and draw rainfall, surface, drain and creek as a connected diagram.
  2. Add infiltration as a branching pathway rather than sending every drop to the outlet.
  3. Connect the two measurements to the model and calculate the difference in runoff volume.
  4. Sketch a planted-strip proposal with a before-and-after monitoring plan and an explicit limitation.

Make the thinking visible

Worked example or model response

The supplied model difference is 85 − 30 = 55 mL of outlet runoff per 100 mL input. This supports investigating a permeable design, but it does not establish a 55% reduction at every real site. Actual conditions may differ from the controlled model.

Guided practice

Together locate where a monitoring device would need to measure outflow to test the proposal fairly. Keep the watershed boundary consistent.

Independent practice

Write a five-sentence design proposal stating the problem, a runoff pathway, the proposed change, a measurement to collect and a limitation. Include the two model numbers.

Quick assessment

Would lower runoff volume alone prove the water is safe to drink? Why?

Answer key & assessment criteria

Answers and teaching guidance

  1. Guided: Measure at the same outlet before and after comparable rainfall; also record rainfall so inputs can be compared.
  2. Independent: Criteria include a planted/permeable change, correct pathway, 85 versus 30 mL evidence and repeated comparable-input measurements. Accept alternatives supported by the same principles.
  3. Quick check: No. Runoff volume does not measure contaminants or drinking-water safety.

Look for: Look for a claim that answers this lesson’s question, accurate use of the supplied evidence and an explanation of a limit or alternative. Ask the learner to point to the detail supporting each inference.

Make it work for your learner

More support

Use a partially drawn watershed with one missing branch and a sentence frame for the monitoring plan.

Extension challenge

Compare runoff per unit rainfall across several storms and explain why a single unusually dry day would be a poor before-and-after test.

Selected contributions · Official sources

Standards connections

Selected NGSS band contribution; not complete performance expectation coverage.

Contributes to NGSS performance expectation

MS-ESS3-3

NGSS · Grades 6–8 band

Design ways to monitor and reduce human environmental impacts.

Read the official performance expectation ↗

The paper proposal applies infiltration and monitoring principles to one environmental impact. It does not build, implement or test a real mitigation system or establish water-quality outcomes.

Source and mapping checked 2026-11-04. This mini-lesson contributes selected skills; it does not claim full attainment.

Supporting Common Core literacy connection

RST.6-8.7

Common Core · Grades 6–8

Connect scientific prose with a diagram, model or table.

Read the official standard ↗

The provided scientific passage/model is explicitly analyzed in the activity. This selected literacy practice does not establish subject-content alignment or complete coverage of the standard.

Source and mapping checked 2026-11-04. This mini-lesson contributes selected skills; it does not claim full attainment.