CLASS 9 · SCIENCE · CHAPTER 1
Simple answers to the chapter activities, examples, reflection prompts, and questions about scientific models and evidence.
11 worked answers · short steps first, explanations when you need them
Textbook pages 1–7
Question Activity 1.1
Keep distance, speed, route, and major stops; ignore unrelated details.
Keep distance, speed, route, and major stops; ignore unrelated details.
Question Example 1.1
Keep speed, direction, and gravity; ignore colour and other small details at first.
Keep speed, direction, and gravity; ignore colour and other small details at first.
Question Example 1.2
Measure humidity, wind, temperature, and compare with past rain patterns.
Measure humidity, wind, temperature, and compare with past rain patterns.
Question Ready to Go Beyond 1
Use measurable evidence and check whether the prediction comes true.
Use measurable evidence and check whether the prediction comes true.
Question Ready to Go Beyond 2
Using 250 g per person each day gives roughly 30 kg per month for four.
Using 250 g per person each day gives roughly 30 kg per month for four.
Question Example 1.3
About 10,000 L per day using simple assumptions.
About 10,000 L per day using simple assumptions.
Question Pause and Ponder 2
Planning may use estimates; medicine doses need exact measurements.
Planning may use estimates; medicine doses need exact measurements.
Question Pause and Ponder 3
A pressure cooker uses physics, chemistry, biology, and mathematics.
A pressure cooker uses physics, chemistry, biology, and mathematics.
Question Threads of Curiosity
c comes from celeritas, the Latin word for speed.
It is a historical symbol for the speed of light.
Question Scientific terms
A law describes; a theory explains; a principle guides reasoning.
A law describes; a theory explains; a principle guides reasoning.
Question Models
Models simplify complex things so we can study the important parts.
Models simplify complex things so we can study the important parts.