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A bag with thin straps hurts your shoulders. A bag with wide straps does not. Both bags weigh the same.

This is Chapter 6, Pressure, Winds, Storms, and Cyclones.

What you will learn

• Force over area — why a small area presses harder.
• Liquids press too — deeper water presses harder.
• The air presses — air has weight.
• Why you are not crushed — equal pressures balance.
• High to low — wind blows from high pressure to low.
• Warmth starts wind — warm air rises.
• Breezes — land and sea breezes.
• Cyclones — a storm that spins.
• Fast air — fast air has lower pressure than still air beside it.
• Lightning — charge, thunder and staying safe.

Need a quick recap?

• A push or a pull (Exploring Forces) — a force pushes or pulls.
• When forces balance (same track) — equal forces cancel.
• Convection (Heat Transfer in Nature) — warm air or water rises.
• The water cycle (A Journey through States of Water) — vapour makes rain.
• Area in squares (Perimeter and Area) — the flat space a shape covers.

Stay safe

Nothing here needs a real storm. Everything here is on the screen. Never go outside to watch a storm.