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Lesson plan Grade 5 Engineering & Design

Larkspur Water Tower: A Grade 5 Steady-Pressure Design Lesson

A grade 5 engineering lesson where students design a model water tower for Larkspur Elementary and calculate its rectangular tank storage in cubic feet and gallons.

Objectives

  1. Students will define the water-tower design problem by naming its success criteria and material constraints.
  2. Students will calculate the storage volume of a rectangular tank in cubic feet and convert it to gallons.
  3. Students will build and test a model water tower and explain how its height affects steady flow.

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: storage tank, volume, criteria, constraint, gallon

Teacher overview

Larkspur is a small, fictional town whose elementary school wants a steady flow of water for its garden taps, even when many taps open at once. Real towns solve this with a water tower: a tank held up high so gravity gives the water a steady push downward. In this lesson students act as engineers, defining what a good tower must do, calculating how much a rectangular tank can hold, and then building and testing a small model. A common misconception this lesson corrects is that a bigger tank alone gives stronger flow; students learn that the tank's height, not just its size, is what keeps the push steady as the tank drains.

Procedure

Hook (5 min): Fill a bottle that has tubing running from a hole near its base. Hold the tube end at basin level and the bottle up high, and let the water run from the tube end into the basin; then refill, lower the bottle close to the basin, and let it run again with the tube end at the same spot. Ask students which pour looked stronger and steadier. Record their guesses without comment.

Frame the design problem (10 min): Tell students that Larkspur Elementary needs a model tower. As a class, write the success criteria on the board: the tower must hold enough water for a full watering, and the flow must stay steady, not slow to a trickle. Then write the constraints: a fictional budget for materials, a height the tower must reach, and only the materials on the table. Explain that criteria are what success looks like and constraints are the limits engineers must respect.

Model the tank volume math (10 min): Model handout question 1 on the board. A rectangular tank 8 feet long, 6 feet wide, and 5 feet deep holds V = 8 x 6 x 5 = 240 cubic feet. Then model the conversion in question 2: 240 cubic feet x 7.48 gallons per cubic foot = 1,795.2 gallons. Walk through the reasoning so students see volume as length times width times depth, not just length times width.

Design and build (20 min): In teams of three or four, students sketch a tower, then build the stand and mount their bottle "tank" on top. Remind them of the fictional budget and the height constraint written earlier. As they build, they complete handout questions 3 through 7, which compare two tank designs and check a materials cost against the budget.

Test and record (10 min): Each team runs tubing from the hole near the bottle's base down to a tap end held at basin level, fills its tank, and compares the stream from the tube end with the tower tall and with the tower short, watching whether the stream stays steady as the tank empties. Teams record what they saw and answer handout question 8 about why a taller tower gives steadier flow.

Closure and exit ticket (5 min): Collect the handouts. As an exit check, ask every student to answer on a slip: "A tank is 4 feet long, 3 feet wide, and 2 feet deep. What is its volume in cubic feet?" Scan for the correct method (multiplying all three dimensions). If fewer than three-quarters of the class multiply all three numbers, reteach the volume step at the start of the next session.

Larkspur Water Tower: A Grade 5 Steady-Pressure Design Lesson — Grade 5 Engineering & Design
Name: ____________________________ Date: ______________

Student Handout

Larkspur is a fictional town, and every number below is part of that made-up scenario. Show your work.

  1. Larkspur's town water tower has a rectangular storage tank that is 8 feet long, 6 feet wide, and 5 feet deep. Find its volume in cubic feet using V = length x width x depth.
  2. One cubic foot of water is 7.48 gallons. Convert your answer from question 1 into gallons.
  3. A second tank design is 10 feet long, 6 feet wide, and 4 feet deep. Find its volume in cubic feet.
  4. Which design holds more water, the tank in question 1 or the tank in question 3? Show the volume of each.
  5. Larkspur Elementary uses about 150 gallons of water for its garden each day. If a full 1,795.2-gallon tank is never refilled, for how many full days can it water the garden?
  6. Your model tank is a small box 20 centimeters long, 10 centimeters wide, and 8 centimeters deep. Find its volume in cubic centimeters.
  7. Your team has a fictional budget of $6. Foam blocks cost $2 each and a bottle costs $1. Your tower uses 2 foam blocks and 1 bottle. Find the total cost and tell whether it stays within the $6 budget.
  8. Why does a taller tower give steadier flow than a short one, even after the tank starts to empty? Explain in one or two sentences.

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: 240 cubic feet. V = 8 x 6 x 5 = 240 cubic feet. Students who multiply only length by width (48) forgot the depth.
  2. Answer: 1,795.2 gallons. 240 cubic feet x 7.48 gallons per cubic foot = 1,795.2 gallons.
  3. Answer: 240 cubic feet. V = 10 x 6 x 4 = 240 cubic feet.
  4. Answer: They are equal. Both tanks hold 240 cubic feet, because 8 x 6 x 5 and 10 x 6 x 4 both equal 240, even though the shapes differ.
  5. Answer: 11 full days. 1,795.2 gallons divided by 150 gallons per day equals 11.968, so the tank supplies 11 complete days of garden water.
  6. Answer: 1,600 cubic centimeters. V = 20 x 10 x 8 = 1,600 cubic centimeters.
  7. Answer: $5, within budget. Two foam blocks at $2 each is $4, plus a $1 bottle, is $5 total, which is $1 less than the $6 budget.
  8. Answer: A taller tower holds the water higher above the taps, so gravity keeps pushing it down with a steady force. Even as the tank drains, the water surface is still well above the taps, so the flow does not weaken quickly.

Differentiation

Support

Give these students a tank with the volume of question 1 already computed and a place-value chart for the multiplication. Provide a printed rule strip that reads "cubic feet x 7.48 = gallons" so they can focus on the design and build without recalling the conversion.

Extension

Ask these students to design a third tank with a different shape that still holds exactly 240 cubic feet, then prove it with the volume formula. Have them explain why a utility might choose a tall, narrow tank over a short, wide one that holds the same amount.

ELL supports

Pre-teach "criteria," "constraint," "volume," and "gallon" with a labeled diagram of a water tower, marking length, width, and depth on the tank. Provide sentence frames for question 8: "A taller tower gives steadier flow because ___."

Extensions

Invite a public works employee or a parent who works in construction to visit and describe how a real tank's size is chosen for a neighborhood. Students can measure a nearby standpipe or water tower from a safe distance, estimate its height, and discuss why it sits on the highest ground in town.