Chapter focus
Relate pressure to force spread over area and use pressure differences to explain air movement and weather hazards.
These are original study notes and practice questions prepared for revision. Use your assigned NCERT edition for the complete lesson, diagrams, activities, and exercise wording.
What you will learn
- Explain the main idea: Relate pressure to force spread over area and use pressure differences to explain air movement and weather hazards.
- Use the key terms and relationships in the notes below.
- Show your reasoning and check whether an answer fits the question.
Key ideas and notes
- Pressure = force ÷ area; for the same force, a smaller area gives greater pressure.
- Air moves from higher-pressure regions toward lower-pressure regions, creating wind.
- Storms and cyclones can bring dangerous winds and rain; official warnings and safe shelter matter.
Worked example
A 200 N force over 2 m² produces pressure 100 Pa.
Quick revision
Pressure = force ÷ area; for the same force, a smaller area gives greater pressure.
Air moves from higher-pressure regions toward lower-pressure regions, creating wind.
Storms and cyclones can bring dangerous winds and rain; official warnings and safe shelter matter.
Original practice questions
Try each question first. Open the answer to check your reasoning.
Find pressure from 60 N over 3 m².
Answer: 20 Pa.
Why can a sharp nail pierce more easily than a blunt one?
Answer: Its force acts over a smaller area, giving greater pressure.
Name one safe action during an official cyclone warning.
Answer: Follow local authorities, move to designated shelter, and stay away from windows/coastline as directed.
Chapter summary
Relate pressure to force spread over area and use pressure differences to explain air movement and weather hazards. The key ideas above give you a short revision path; practise explaining them in your own words and revisit any step you could not justify.