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Classroom activity Grade 5 Math

Build-a-Tank Relay: A Grade 5 Unit Cube Volume Station Activity

A grade 5 team relay where students build rectangular water-tank models from interlocking unit cubes to match target volumes, then compare shapes that share a volume.

Objectives

  1. Students will build a rectangular prism from unit cubes to match a given target volume.
  2. Students will record the length, width, and height of their built tank and multiply to confirm its volume.
  3. Students will compare tanks with the same volume but different dimensions to conclude that different shapes can have the same volume.

Vocabulary

Key words: unit cube, volume, rectangular prism

Teacher overview

This is a small-team relay for 4 to 6 teams of 3 to 4 students, played with sets of interlocking unit cubes. Each team's cubes represent the storage tank a water utility might build, and every round asks a team to physically build a rectangular prism whose total number of unit cubes matches a target volume printed on a card, turning the abstract idea of "volume" into a structure students can stack, count, and compare.

Activity Directions

  1. Before class, gather at least 30 interlocking unit cubes for each team and prepare four target-volume cards reading "12 cubic units," "18 cubic units," "24 cubic units," and "30 cubic units."
  2. Divide the class into teams of 3 to 4 students, and give each team a set of unit cubes and a recording sheet with columns for Round, Target Volume, Length, Width, Height, and Check.
  3. Explain the rule: each round, a team draws the next target-volume card and has 4 minutes to build a rectangular prism (a tank shape with no gaps or overhangs) using exactly that many unit cubes.
  4. Once a team finishes building, they record the length, width, and height they used on their recording sheet, then multiply the three numbers in the "Check" column to confirm the product matches the target volume.
  5. Run Round 1 with the "12 cubic units" card. After 4 minutes, call time and have each team hold up its tank for a quick visual check before moving to Round 2.
  6. Repeat the same 4-minute build-and-check process for Round 2 ("18 cubic units"), Round 3 ("24 cubic units"), and Round 4 ("30 cubic units"), having teams take their tank apart and return every cube to their pile before each new round.
  7. End the activity after all four rounds are complete, or after 25 minutes total, whichever comes first.
  8. Gather the class and run the debrief: ask two or three teams to share the dimensions they used for the same target volume, and compare whether every team built the same shape.

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: dimensions with product 12.
    Any three whole numbers whose product is 12 are correct, such as 2 x 2 x 3 or 1 x 3 x 4.
  2. Answer: dimensions with product 18.
    Any three whole numbers whose product is 18 are correct, such as 2 x 3 x 3 or 1 x 2 x 9.
  3. Answer: dimensions with product 24.
    Any three whole numbers whose product is 24 are correct, such as 2 x 3 x 4 or 2 x 2 x 6.
  4. Answer: dimensions with product 30.
    Any three whole numbers whose product is 30 are correct, such as 2 x 3 x 5 or 1 x 5 x 6.
  5. Answer: Yes, both teams were correct.
    Debrief question: "Two teams both built tanks with a volume of 24 cubic units but used different dimensions. Were both teams correct?" Both teams were correct, because volume only depends on the total number of unit cubes packed inside the shape, not on the particular length, width, and height used to arrange them.

Differentiation

Support (below grade level)

For the first round, give struggling teams one correct set of dimensions already written on their recording sheet (for example, "2 x 2 x 3 for 12 cubic units") so they can build to a known target before trying the remaining rounds independently.

Extension (above grade level)

Challenge advanced teams to find every possible set of whole-number dimensions for the 24-cubic-unit target and record all of them, then identify which set produces the flattest shape and which produces the most cube-like shape.

ELL supports

Model the first round's build in front of the whole class before teams begin, narrating each step aloud ("I am placing 2 cubes, then 2 more beside them to make one layer of 4"). Provide a labeled recording sheet with picture icons next to "Length," "Width," and "Height."