Grade 2 Science Week 4 | Student Textbook

Grade 2 | SCIENCE

WEEK 4 • STUDENT TEXTBOOK • DAYS 16–20

Read each lesson with a parent or teacher and study the worked example. Then answer the questions for that day in the Week 4 Practice Workbook.

Day 16: Do Plants Need Light?

Plants use light to make food in their leaves. Without light, a plant cannot make enough food.

A plant kept in the dark may grow tall and thin as it stretches to find light. Its leaves may turn pale or yellow because it cannot make the green color it uses to make food.

Worked example: A seedling under a box grew long and pale. What need was missing?

Under a box, the seedling got no light.
Long, thin and pale growth is a sign of missing light.

Worked answer: Light was missing.

Day 17: Measuring Plant Growth

To compare plants fairly, scientists measure them. Place the zero end of a ruler at the soil and read the number at the top of the plant.

Measure each plant the same way, on the same days. Write each measurement in a table with its unit, such as centimeters.

Worked example: A ruler’s zero is at the soil, and the top of the plant reaches the 7. How tall is the plant?

The ruler starts at zero at the soil.
The top of the plant lines up with 7.
The ruler is marked in centimeters.

Worked answer: The plant is 7 cm tall.

Day 18: Comparing Results

When you compare results, look at all the data, not just one number. Height, color, strength and leaf size are all observations.

A good comparison names both plants and tells how they are alike or different.

Worked example: Plant A has 8 large green leaves. Plant B has 3 small yellow leaves. Compare the leaves.

Count: Plant A has 5 more leaves than Plant B.
Color: A is green, B is yellow.
Size: A’s leaves are larger.

Worked answer: Plant A has more, larger and greener leaves than Plant B.

Day 19: Drawing a Conclusion

A conclusion answers the question the test asked. It must be based on the evidence, which is the data you collected.

A good conclusion says what you found and names the evidence: Plants need light to grow well, because the plant in the sun was green and strong, but the plant in the dark was pale and weak.

Worked example: A test asked whether radish seeds need water to sprout. Seeds with water sprouted in 4 days. Dry seeds did not sprout. What is the conclusion?

The question was about water.
Evidence: watered seeds sprouted; dry seeds did not.

Worked answer: Radish seeds need water to sprout, because only the watered seeds sprouted.

Day 20: Independent Check: Light and Plant Growth

Today you will read a new test and answer on your own.

Use what you learned: find the variable, read measurements, compare plants and write a conclusion.

Worked example: A ruler’s zero is at the soil and the plant reaches 12. How tall is it?

The ruler starts at zero at the soil.
The top lines up with 12 centimeters.

Worked answer: 12 cm.