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Grade 2 Science Week 15 | Student Textbook

Grade 2 | SCIENCE

WEEK 15 • STUDENT TEXTBOOK • DAYS 71–75

Read each lesson with a parent or teacher and study the worked example. Then answer the questions for that day in the Week 15 Practice Workbook.

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

Many objects are made of smaller pieces. A toy house can be built from blocks, and a necklace can be made from beads. The pieces are the parts of the object.

If you take an object apart, you can use the same pieces to build something new. The pieces do not change. Only the way they are put together changes, so the new object can have a different shape and a different use.

Worked example: Can the same 10 blocks be built into a car and then into a boat?

  1. Take the car apart into its 10 blocks.
  2. Put the same 10 blocks together in a new way.

Worked answer: Yes. The same blocks can be arranged into a new object.

Day 72: Build, Take Apart and Rebuild

Engineers often build a model, take it apart and use the pieces again. Counting the pieces before and after shows that nothing was added or lost.

When you rebuild, the object can change shape and do a new job. A tower is tall and can be seen from far away. A bridge is long and lets things cross a gap.

Worked example: Why should you count the blocks after you take the tower apart?

  1. Counting again checks the number of pieces.
  2. It shows that the same pieces will be used for the new object.

Worked answer: To show that no blocks were added or lost.

Day 73: Shapes and Joins That Make Structures Stronger

A structure is something built to stand up or hold weight, such as a tower, a wall or a bridge. Some ways of putting pieces together make a structure stronger.

A wide base helps a tower stand without tipping. Overlapping the pieces, the way bricks are laid in a wall, helps the pieces hold each other in place. Triangles are strong shapes that do not bend easily.

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

  1. A wide base spreads the weight out.
  2. A spread-out base is harder to tip.

Worked answer: The tower with a wide base.

Day 74: Plan, Test and Improve a Design

Engineers plan a design, build it, test it and then improve it. They often take a model apart and use the same pieces in a better way.

To compare two designs fairly, test them the same way. Use the same gap, the same pieces and the same test, so the only difference is the design.

Worked example: Why should both bridges cross the same 6-inch gap?

  1. A wider gap would be harder to cross.
  2. Keeping the gap the same makes the test fair.

Worked answer: So the only difference is the design.

Day 75: Independent Check: Taking Apart and Rebuilding

Today you will answer on your own.

Use what you learned this week: the same pieces can make different objects, and some ways of putting pieces together make a structure stronger.

Worked example: A necklace is taken apart, and its beads are used to make a bracelet. Are the beads new?

  1. The beads came from the necklace.
  2. They were put together in a new way.

Worked answer: No. The same beads were reused.

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