Exercise Questions and Answers
Q1: Why is one side of a puri thinner than the other?
A1: One side of a puri may be thinner due to uneven rolling of the dough or the way it is dropped into hot oil. When fried, the dough puffs up as water inside turns to steam, pushing the dough outward. If one side is thinner, it expands more, creating a thinner layer compared to the thicker side. Experimenting with dough thickness or dropping methods (e.g., vertical vs. angled) can test this (Page 6).
Q2: Are there more grains of sand on all the beaches and deserts of the world, or more stars in our galaxy?
A2: Estimating this involves comparing large quantities. A single beach may contain billions of sand grains (e.g., a cubic meter of sand has ~1 billion grains). Earthβs beaches and deserts could have ~10^22 to 10^23 grains. The Milky Way has ~100-400 billion stars (~10^11 to 4×10^11). Sand grains likely outnumber stars due to the vast volume of Earthβs beaches and deserts, but precise calculations require more data (Page 1).
Q3: Why has nature created such a vast variety of plants and animals?
A3: The vast variety of plants and animals results from evolution through sexual reproduction, where genetic mixing creates diverse traits. This diversity allows species to adapt to different environments (e.g., deserts, forests, oceans), enhancing survival. Ecosystems benefit from this variety, as each species plays a role in maintaining balance (Pages 1, 5).
Q4: Is there such a question that makes you curious about the world? Write it here!
A4: Example question: Why do some clouds produce rain while others donβt? This sparks curiosity about weather patterns, water cycles, and atmospheric conditions, encouraging observation and investigation (Page 1).
Q5 (Implied from Discover, design, and debate): Design an experiment to investigate why a puri puffs up and why one side is thinner.
A5:
- Question: What factors affect a puriβs puffing and why is one side thinner?
- Hypothesis: Thinner dough or specific dropping methods cause uneven puffing.
- Experiment:
- Prepare dough circles of different thicknesses (e.g., 1 mm, 2 mm, 3 mm) using the same flour (maida).
- Heat oil to a constant temperature (e.g., 180Β°C).
- Drop dough in two ways: vertically and at an angle.
- Observe and measure: Does it puff up (yes/no)? Time to puff (seconds)? Thickness of each side (mm).
- Control: Use the same oil, temperature, and flour type, changing only one variable (thickness or dropping method) at a time.
- Expected Results: Thinner dough may puff faster but have a thinner side due to greater steam expansion. Vertical dropping may create more uniform puffing than angled dropping (Page 6).