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Classroom activity Grade 5 Science

Lifting Water Uphill: A Grade 5 Timber Ridge Hand-Crank Lift Challenge

A grade 5 build activity in which groups lift a cup of water uphill on a narrow pencil axle and a wide tube axle, then compare turns and spills.

Objectives

  1. Students will build two versions of a hand-crank lift that raises water from a low basin to a raised basin, using a narrow axle and a wide axle.
  2. Students will test and record how many turns each axle design needs to lift the same cup of water the same height.
  3. Students will compare the two designs and explain the trade-off between fewer turns and the force each turn requires.

Vocabulary

Pump
A pump is a machine that adds energy to water to move it or push it uphill, doing the job gravity cannot do on its own. Water systems use many different kinds of pumps to move water from wells, through treatment, and out to customers.

Also: axle, mechanical advantage, circumference, effort

Teacher overview

The Timber Ridge community garden, a fictional garden used for this activity, sits on a slope above a rain barrel that collects water for the garden's plants. Volunteers there have no electric outlet nearby, so they need a hand-powered way to lift water about a foot uphill from the low barrel to a raised garden barrel. In this build activity, each group constructs two versions of the same simple hand-crank lift, one wound around a narrow pencil axle and one wound around a wide cardboard-tube axle, then tests which design lifts water to the garden barrel using fewer hand turns. A common misconception this activity addresses is that a "better" design always means less effort overall; the wide axle needs fewer turns but each turn is harder to make, since it winds a longer length of string with every full turn of the hand.

Activity Directions

  1. Set the low basin on the floor or a table, filled with about 4 cups of water, and set the raised basin on a stack of books or a chair so its rim sits at least 12 inches above the low basin's water surface.
  2. Tie one end of a length of string securely through both holes punched near the rim of the small cup, so the cup hangs level when lifted by the string.
  3. Build Version 1 (narrow axle): Tape the free end of the string to the pencil and wind the string around the pencil several times, so that turning the pencil by hand reels the cup upward. Position the pencil so that winding it lifts the cup from the low basin toward the raised basin's rim. Tape a craft stick across one end of the axle as a crank handle, using the same length of stick on both versions.
  4. Build Version 2 (wide axle): Using a fresh length of string tied to the same cup, tape the string to the cardboard tube instead of the pencil and repeat the winding setup, so the same cup can now be lifted using the wider tube as the axle. Tape a craft stick across one end of the axle as a crank handle, using the same length of stick on both versions.
  5. Label the two builds "Version 1: Pencil Axle" and "Version 2: Tube Axle" so your group can keep the results separate during testing.
  6. Test Version 1: Dip the cup into the low basin to fill it with water, then turn the pencil axle by its crank handle, counting out loud how many full turns it takes to lift the full cup to the raised basin's rim and dump the water in. Record the number of turns and whether the cup arrived full, partly spilled, or empty.
  7. Repeat the Version 1 test two more times, for three trials total, recording each trial's turn count and spill result on the recording sheet.
  8. Test Version 2: Before testing Version 2, pour the water from the raised basin into the measuring cup, record the Version 1 total, and return the water to the low basin. Then repeat steps 6 and 7 using the wide cardboard-tube axle, recording three trials of turn counts and spill results in the same way.
  9. After the Version 2 trials, use the measuring cup to measure the water in the raised basin and record the Version 2 total.
  10. Gather as a class once every group has finished both versions, and bring your recording sheets to the debrief discussion.

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. Expected result: Version 2 (the wide tube axle) should lift the cup to the raised basin using fewer turns than Version 1 (the narrow pencil axle), because winding string around a larger circumference raises the cup a greater distance with every single turn.
  2. Debrief question: "Which version would you choose if your arm got tired quickly during many lifts, and which would you choose if you needed to lift water fast?" Answer: The narrow pencil axle (Version 1) takes more turns but each turn requires less force, so it may feel easier to sustain over many lifts; the wide tube axle (Version 2) takes fewer turns to finish each lift, so it is faster, but each turn requires more force to make.
  3. Debrief question: "Why did the water totals in steps 8 and 9 sometimes come out lower than 3 full cups even when 3 successful trials were run?" Answer: Spilling during the lift, especially if the cup tipped while winding quickly, reduced the amount of water that actually reached the raised basin, which is why recording spill results alongside turn counts matters for a fair comparison.
  4. Science fair note: If entering this comparison as a science fair investigation, display each version's average number of turns per trial and total water delivered on a labeled bar graph, alongside a photo or diagram of both builds and a short written explanation of the mechanical-advantage trade-off between them.

Differentiation

Support (below grade level)

Pre-build Version 1 for struggling groups so they can focus on building and testing only Version 2, then compare their Version 2 results against the pre-built Version 1's turn count provided by the teacher.

Extension (above grade level)

Ask advanced groups to build a third version using an axle even wider than the cardboard tube, such as a small plastic cup taped sideways, predict how many turns it will need before testing, and check whether the pattern of fewer turns but more force per turn continues.

ELL supports

Demonstrate both builds once at the front of the room before groups begin, narrating each step aloud while pointing to the materials. Provide a simple recording sheet with icons (a pencil, a tube, a cup, a checkmark) instead of relying only on written words for the trial log.

Extensions

Research the Archimedes screw, a real spiral pump design used to lift water uphill without electricity, and compare its shape and motion to the wound-string axle lifts built in this activity, discussing what the two designs have in common.