Question Opening question 1
Why can one side of a puri be thinner than the other?
Steps only
Uneven dough thickness or puffing can make one side thinner.
Answer
It may depend on how the dough is rolled and how it puffs while frying.
CLASS 8 · SCIENCE · CHAPTER 1
Exploring the Investigative World of Science
Sample answers to the chapter’s opening questions and an easy investigation plan for studying how puris puff.
5 worked answersComplete chapter answers
5 worked answers · short steps first, explanations when you need them
Probe and Ponder
Textbook pages 1–7
Question Opening question 2
Are there more grains of sand on the world’s beaches and deserts, or more stars in our galaxy?
Steps only
Both are estimated, not counted one by one; define the area and use samples.
Answer
Compare scientific estimates and explain their assumptions.
Question Opening question 3
Why is there such a wide variety of plants and animals in nature?
Steps only
Different environments and adaptations contribute to the variety of living things.
Answer
Biodiversity developed through variation and adaptation over many generations.
Question Opening question 4
Write one question about the world that makes you curious.
Steps only
Ask a specific question that can be explored with observations or a fair test.
Answer
Example: Does sunlight affect how quickly a seedling grows?
Question Chapter investigation
How could you investigate which factors affect how a puri puffs, while keeping the test fair?
Steps only
Change one factor, keep the rest the same, record observations, and repeat. An adult must handle hot oil.
Answer
A fair test changes one factor at a time.