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Classroom activity Grade 3 Engineering & Design

Hartsmere Ridge Land Placement: A Grade 3 Design Challenge

A grade 3 model watershed challenge where teams place land cards and one grass strip on a paper ridge, then test two placements to protect a town water intake.

Objectives

  1. Students will show that water runs downhill across a model ridge into one low corner.
  2. Students will place a grass strip to keep colored runoff away from a water intake.
  3. Students will compare two placements using the same number of squirts.

Vocabulary

Watershed
A watershed is all the land where rain that falls will drain to the same stream, river, or lake. Everyone lives in a watershed, no matter how far from the water they live.

Also: runoff, intake, grass strip

Teacher overview

Teams of three or four build a paper model of a fictional ridge above the town of Hartsmere, place land cards on it, and then design the one piece of protection they are allowed: a single grass strip that must keep dirty runoff out of the town's water intake. The model carries the idea on its own, because the crumpled paper gives every team real high ground and low ground, and the spray bottle makes water take the route the land actually offers rather than the route a student expects. Many students hear the word watershed and picture a building or a pond, and they assume only the ground right beside the intake matters, which often leads them to place the grass strip at the water's edge. The two rounds let a team discover for itself that a strip placed higher up, across the path the water takes, can do more.

Activity Directions

  1. Before class, crumple one sheet of paper per team, open it part way, and set it in a tray so it holds ridges and valleys. Put a blue sticker in the lowest corner of each model and tell teams this is the Hartsmere town water intake. Write School along one high edge of each tray and tell teams the Parking Lot must touch that edge. Cut five land cards per team and label them Parking Lot, Ball Field, Barn, Tree Lot, and Grass Strip.
  2. Gather the class and state the design problem. Hartsmere takes its drinking water from the low corner of the valley. Rain washes loose soil and barn waste downhill. The team must place the land cards so that as little dirty water as possible reaches the intake.
  3. State the three goals and the three limits, and write them where every team can see them. The goals are to keep colored water away from the blue sticker, to keep the Parking Lot card touching the school edge of the tray, and to use the Grass Strip exactly once. The limits are one Grass Strip card per team, all cards lying flat, and twenty squirts from the same bottle in every test.
  4. Give teams five minutes to trace the water's likely route with a blue marker before any card is placed. This forces a prediction on paper that the test can later confirm or overturn.
  5. Have teams scribble with the brown marker on the Barn card area and on any bare high ground. Explain that the brown marks stand for loose soil and barn waste that rain can pick up.
  6. Teams place all five cards, including the Grass Strip in the spot they think protects the intake best. Each team writes the Round 1 position of the Grass Strip on the handout before testing.
  7. Run Round 1. One team member gives exactly twenty squirts, held about 20 centimeters above the highest part of the model, spread evenly over the high ground. The team watches where the brown color travels and records how much of it reached the blue sticker using the words none, a little, or a lot.
  8. Run Round 2. Teams move the Grass Strip and nothing else, then repeat with the same bottle and the same twenty squirts. Before Round 2, blot the model with a paper towel, put a fresh blue sticker in the same corner, and scribble brown again on the same spots. Say plainly that moving two things at once would make the two rounds impossible to compare.
  9. Stop the building after Round 2. Teams circle their better placement on the handout and write the reason.
  10. Debrief with the whole class. Ask which teams did better with the strip near the sticker and which did better with the strip higher up, then ask the question that ties the model back to the land it stands for: what did the shape of the paper decide before anyone placed a single card?
Hartsmere Ridge Land Placement: A Grade 3 Design Challenge — Grade 3 Engineering & Design
Name: ____________________________ Date: ______________

Student Handout

Write your team name at the top. Answer every question in order.

  1. Before testing, draw an arrow on your model showing where you think the water will go. Where did you predict the water would end up?
  2. Where did your team put the Grass Strip in Round 1?
  3. In Round 1, how much brown color reached the blue sticker? Write none, a little, or a lot.
  4. Where did your team put the Grass Strip in Round 2?
  5. In Round 2, how much brown color reached the blue sticker? Write none, a little, or a lot.
  6. Which round protected the intake better? Tell how you know.
  7. Why did both rounds use the same twenty squirts from the same bottle?
  8. Name one spot on your model where a second grass strip would help most, and say why.

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: Accept any prediction that names a downhill route toward the low corner. Students who predict the water spreading evenly or running uphill have a useful starting point for the debrief, so mark the prediction on effort rather than accuracy.
  2. Answer: Accept any clearly described position, such as right beside the blue sticker or across the middle of the main valley. The position must be specific enough that a reader could put the card back in the same place.
  3. Answer: Accept none, a little, or a lot, whichever the team observed. A strip laid only at the water's edge usually still lets a lot of color arrive, because the water reaches it already carrying color.
  4. Answer: Accept any position that differs from the Round 1 position. If a team did not move the card, the two rounds cannot be compared and the team should rerun Round 2.
  5. Answer: Accept none, a little, or a lot, whichever the team observed.
  6. Answer: Accept either round, provided the reason names the amount of color at the sticker in both rounds. A strong answer compares the two records directly rather than saying one looked better.
  7. Answer: Accept any answer saying the test would not be fair otherwise. Using the same bottle and the same twenty squirts means the only change between rounds is where the Grass Strip sits, so the difference in the result comes from the placement.
  8. Answer: Accept any spot on high ground or across a valley the water clearly follows, with a reason tied to stopping color before it travels far. Spots at the sticker itself should be questioned with the Round 1 evidence.

Differentiation

Support

Pre-place the four land cards for these teams so their only decision is the Grass Strip, and give them a model with one obvious valley rather than several. Provide a picture choice board of three marked strip positions to point at before they write question 2.

Extension

Give these teams a second Grass Strip for a third round and require them to state, before testing, which of the two strips they expect to matter more. Ask them to write a rule other teams could follow when placing a strip on any model.

ELL supports

Pre-teach intake, uphill, runoff, and strip with gestures and a labeled model that stays on display. Provide the frames "The water went ___" and "Round ___ was better because ___." Allow answers to questions 2 and 4 to be drawn on a small map of the tray instead of written.

Extensions

Give the class a printed map of the real land around the school and ask which way water would leave the playground in heavy rain. Teams can mark one spot where a strip of grass or a row of shrubs would sit across that route and explain the choice with the evidence from their own two rounds.