Grade 2 Science Week 14 | Student Textbook

Grade 2 | SCIENCE

WEEK 14 • STUDENT TEXTBOOK • DAYS 66–70

Read each lesson with a parent or teacher and study the worked example. Then answer the questions for that day in the Week 14 Practice Workbook.

Week 14 Student Textbook | Week 14 Practice Workbook | Week 14 Teacher Guide | Week 13 Student Textbook | Grade 2 index

Day 66: Testing Strength

Strength is how well a material holds weight without bending or breaking. Builders choose strong materials for bridges, shelves and chairs.

The shape of a material can change its strength. A sheet of paper folded back and forth like a fan can hold much more than the same sheet lying flat. Test materials to find out, instead of guessing.

Worked example: Why should every bridge cross the same 6-inch gap?

A wider gap would be harder to hold up.
Keeping the gap the same makes the test fair.

Worked answer: So the only difference is the bridge itself.

Day 67: Testing Absorbency

A material that soaks up water is absorbent. A paper towel and a sponge are absorbent. Water runs off materials that are not absorbent, such as plastic and foil.

Some jobs need an absorbent material, like wiping up a spill. Other jobs need a material that keeps water out, like a raincoat. Testing tells us which material fits which job.

Worked example: Which would be better for drying dishes: a cloth towel or a sheet of foil?

Drying dishes means soaking up water.
Cloth soaks up water; foil does not.

Worked answer: A cloth towel.

Day 68: Flexibility, Hardness and Texture

A flexible material bends without breaking, like a rubber band or a cloth. A hard material does not bend or dent easily, like metal or stone. Texture tells how a material feels.

Every job needs certain properties. A shoe sole needs to be flexible and rough so you do not slip. A cutting board needs to be hard. Choose a material by matching its properties to the job.

Worked example: Why is a garden hose made of a flexible material?

A hose must bend around corners and roll up.
A flexible material bends without breaking.

Worked answer: So it can bend and roll up without breaking.

Day 69: Choose the Best Material for the Job

Engineers choose materials by testing them for the job they must do. A rain hat must keep water out. It should also bend to fit a head.

A good choice uses evidence from more than one property. A material that keeps water out but cracks when it bends would not make a good hat.

Worked example: Why should each cup get the same number of sprays?

More water could soak through any material.
The same number of sprays keeps the test fair.

Worked answer: So the only difference is the material.

Day 70: Independent Check: Testing Materials

Today you will answer on your own.

Use what you learned this week: strength, absorbency, flexibility, hardness and choosing the best material for a job.

Worked example: Is a sponge absorbent?

A sponge soaks up water.
Materials that soak up water are absorbent.

Worked answer: Yes.