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Lesson plan Grade 2 Science

Two Covers for the Ambledown Garden Tub: A Drying Test

A three-session grade 2 test of an open tub against a solid lid and a mesh cover, tracking water lines to find where a garden tub's stored water goes.

Objectives

  1. Students will describe two cover materials by what they can see and feel.
  2. Students will mark and compare the water line in three tubs across five days.
  3. Students will choose a cover for the garden tub and give a reason from the data.

Vocabulary

Key words: cover, mesh, solid, water line, dry up, drops

Teacher overview

The garden crew at the fictional Ambledown School keeps a tub of water beside the beds so nobody has to drag a hose across the yard, and by Friday the tub always holds less water than it did on Monday even though the crew is away all week. This lesson sets three tubs side by side, one open, one under a solid lid, and one under a mesh cover, and has students mark the water line on day 1, day 3, and day 5. Second graders regularly explain the missing water as a slow leak or as water soaking into the tub itself, so the clear tubs matter: nothing runs out the bottom, and the drops that gather under the solid lid on day 5 are the evidence that the water rose into the air and was caught. The mesh cover looks like a real solution and performs almost exactly like no cover at all, which is what makes the comparison worth running.

Procedure

Hook, day 1 (5 min): Describe the Ambledown garden tub, full on Monday and low on Friday, with the gate locked all week so no one touched it. Ask: "Nobody used the tub. Where did the water go?" Collect three ideas on chart paper and leave them up until day 5.

Direct instruction, day 1 (5 min): Tell the class that the garden crew is choosing between two covers and needs to know which one keeps more water in the tub. Pass the solid lid and the mesh square around so every student can look through the mesh and hold the lid up to the light. Ask students to say one thing they notice about each material before the covers go on the tubs.

Guided setup, day 1 (15 min): Fill all three tubs from the same pitcher so the water sits at the same height in each, and let three students check that the levels match by eye. Mark the starting water line on each tub with a thin strip of masking tape. Leave Tub A open. Put the solid lid on Tub B and hold it with a rubber band. Put the mesh square on Tub C and hold it with a rubber band. Set all three in the same sunny spot, out of the way of hands and elbows, and remind students that the tubs are for looking at, not for drinking from. Students draw the three tubs and label the covers on the handout.

Mid-week check, day 3 (5 min): Two students add a second tape strip at the water line on each tub without moving the covers. The class says aloud which tub has dropped the most so far.

Data review, day 5 (10 min): Add the day 5 tape strip to each tub, then lift the solid lid so the class can see the underside. Set the three tubs in a row at the front and have students answer questions 1 through 8 on the handout, using a ruler to compare the gaps between tape strips where it helps.

Formative check, day 5 (3 min): Ask every student to point at the tub they think lost the most water, then at the tub they think lost the least. If more than a few students point at the mesh tub as the one that lost the least, hold Tub A and Tub C side by side at eye level and have the class read the two lowest tape strips together before continuing.

Closure, day 5 (2 min): Return to the day 1 ideas and mark which ones the tubs support. State plainly that water left the open tub by rising into the air, that the solid lid caught it and let it drip back, and that the mesh let it pass straight through.

Two Covers for the Ambledown Garden Tub: A Drying Test — Grade 2 Science
Name: ____________________________ Date: ______________

Student Handout

Day 1. Draw the three tubs. Label the cover on each one.

Day 3 and day 5. Mark where each water line is on your drawing.

Day 5. Answer these questions.

  1. All three tubs held the same water and sat in the same spot. Name the one thing that was different about them.
  2. Write one word that tells what the solid lid is like.
  3. Write one word that tells what the mesh cover is like.
  4. On day 5, which tub had the lowest water line?
  5. On day 5, which tub had the highest water line?
  6. Drops sat on the underside of the solid lid on day 5. Tell where those drops came from.
  7. Rain cannot get through the solid lid, but rain can get through the mesh. Name one thing the mesh cover does better.
  8. The garden crew wants to keep the most water in the tub. Which cover should they use? Tell 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: The cover on top. Tub A had no cover, Tub B had the solid lid, and Tub C had the mesh, while the water, the size, and the sunny spot were the same for all three.
  2. Answer: Accept any word that describes the lid as students see and feel it, such as solid, smooth, hard, closed, or blocking.
  3. Answer: Accept any word that describes the mesh, such as holey, open, see-through, netted, or bumpy.
  4. Answer: Accept the answer that matches the class tubs. In most rooms the open tub, Tub A, or the mesh tub, Tub C, has the lowest line, because neither one stops water from leaving.
  5. Answer: Accept the answer that matches the class tubs. In most rooms Tub B, under the solid lid, has the highest line.
  6. Answer: Accept any answer saying the drops came from the water in the tub, which rose into the air and then collected on the cool lid. Answers that say the drops leaked in from outside should be checked against the dry outside of the lid.
  7. Answer: Accept any answer naming a job the mesh does well, such as letting rain in to refill the tub, letting air through, or keeping leaves and bugs out while still catching rain.
  8. Answer: The solid lid, because the tub under it kept the highest water line. Accept the mesh only when the reason names the rain refilling the tub and acknowledges the greater loss.

Differentiation

Support

Give these students a handout with the three tubs already drawn and labeled, so their job on each check day is only to draw the new water line. Allow questions 4 and 5 to be answered by pointing at a tub, and offer the word choices solid, holey, high, and low as a bank.

Extension

Ask a small group to set up a fourth tub with the solid lid and place it in a shady corner instead of the sunny spot, then compare its day 5 line with Tub B. Have them write whether the sun or the cover made the bigger difference.

ELL supports

Keep a spare piece of each cover material taped beside the matching tub, so "solid" and "mesh" stay attached to something students can touch all week. Provide the sentence frames "Tub ___ lost the most water" and "The drops came from ___," and let students trace the tape strips with a finger while answering.

Extensions

Set out two shallow dishes with the same amount of water, one on a windowsill and one in a closed cupboard, and check them on the same days as the tubs. Ask students which tub each dish behaved like and what that says about the part the sun plays.