Ahava~Love Assembly

Grade 2 Science Week 15 | Teacher Guide

Grade 2 | SCIENCE

WEEK 15 • TEACHER GUIDE AND ANSWER KEY • DAYS 71–75

Read each lesson aloud with the child and model the worked example before practice. Do not show this key during practice. Accept oral, drawn or written answers where the child cannot yet write the whole answer. On Day 75, read aloud if needed but give no hints.

Week 15 Student Textbook | Week 15 Practice Workbook | Week 15 Teacher Guide | Week 14 Student Textbook | Week 16 Student Textbook | Grade 2 index

Day 71: The Same Pieces Can Make Different Objects

Standard: Grade 2 Science Standard 3, 2.3

Practice record: Three builds from one set of 12 blocks, printed on the Week 15 Practice Workbook.

Worked example: Can the same 10 blocks be built into a car and then into a boat? Worked answer: Yes. The same blocks can be arranged into a new object.

  1. 12 blocks each.
  2. The tower.
  3. Take the tower apart into its 12 blocks, then lay the same blocks end to end and stack them low to make a wall. The blocks stay the same; only the way they are put together changes. Accept any answer about taking apart and rearranging the same pieces.

Teaching note: Let the child build two different objects from the same small set of blocks or interlocking bricks, counting the pieces each time.

Day 72: Build, Take Apart and Rebuild

Standard: Grade 2 Science Standard 3, 2.3

Practice record: Sample results, printed on the Week 15 Practice Workbook.

Worked example: Why should you count the blocks after you take the tower apart? Worked answer: To show that no blocks were added or lost.

  1. 20 blocks each.
  2. The bridge (10 blocks long).
  3. No. The table shows 20 blocks for the tower and 20 for the bridge, so the same pieces were used. Only the shape changed. Accept any answer that uses the two counts of 20.

Teaching note: Results vary with the blocks. Use the observation checklist below.

Hands-on task observation checklist (Build a tower, then rebuild it as a bridge). Check each item you observe. Four or five items shows the child met the task goal; two or three means repeat the task with support.

  • ☐ Child counted 20 blocks before building.
  • ☐ Child built a tower and recorded its height.
  • ☐ Child took the tower apart and recounted the blocks.
  • ☐ Child rebuilt the same blocks into a bridge and recorded its length.
  • ☐ Child explained that the pieces stayed the same while the shape changed.

Day 73: Shapes and Joins That Make Structures Stronger

Standard: Grade 2 Science Standard 3, 2.3

Practice record: Sample results: gentle taps before it fell, printed on the Week 15 Practice Workbook.

Worked example: Which is harder to tip over: a tower with a wide base or a tower with a narrow base? Worked answer: The tower with a wide base.

  1. The wide-base tower (7 taps).
  2. 5 more taps (8 – 3 = 5).
  3. The wall with overlapping blocks took 8 taps, but the straight-stacked wall fell after 3. Overlapping pieces hold each other in place, so the wall is stronger. Accept any answer that uses the data.

Teaching note: Show a real brick or block wall and point out how each brick sits across two bricks below it.

Day 74: Plan, Test and Improve a Design

Standard: Grade 2 Science Standard 3, 2.3

Practice record: Sample results, printed on the Week 15 Practice Workbook.

Worked example: Why should both bridges cross the same 6-inch gap? Worked answer: So the only difference is the design.

  1. 15 pennies.
  2. 9 more pennies (15 – 6 = 9).
  3. The second design used two layers, and the top blocks overlapped the joins below, so the pieces held each other in place. The blocks were the same, so the way they were put together made the difference. Accept any answer about the layers or overlapping joins.

Teaching note: Results vary. Praise careful testing and a clear reason for each change. Use the observation checklist below.

Hands-on task observation checklist (Build, test and rebuild a better bridge). Check each item you observe. Four or five items shows the child met the task goal; two or three means repeat the task with support.

  • ☐ Child planned before building.
  • ☐ Child tested with pennies placed one at a time on the middle.
  • ☐ Child took the bridge apart and reused the same blocks.
  • ☐ Child kept the same gap for both tests.
  • ☐ Child used the two results to explain which design was better.

Day 75: Independent Check: Taking Apart and Rebuilding

Standard: Grade 2 Science Standard 3, 2.3

Practice record: Building with 16 craft sticks, printed on the Week 15 Practice Workbook.

Worked example: A necklace is taken apart, and its beads are used to make a bracelet. Are the beads new? Worked answer: No. The same beads were reused.

  1. 16 sticks each.
  2. Any one of: give it a wide base; overlap the pieces; use triangles.
  3. She reused the same pieces. She could count the blocks in the car before taking it apart and count the blocks in the boat. If the counts match, the same pieces were used. Accept any answer that says she reused the pieces and gives a way to check, such as counting.

Teaching note: Independent check: read aloud if needed, but give no hints.

Week 15 Student Textbook | Week 15 Practice Workbook | Week 15 Teacher Guide | Week 14 Student Textbook | Week 16 Student Textbook | Grade 2 index