Winds, Storms and Cyclones

• Understand how air moves (wind) and how pressure differences cause it.
• Understand how wind speed relates to air pressure — fast-moving air exerts less pressure.
• Learn how thunderstorms form and develop into cyclones, and basic safety measures.

1. Air expands on heating and becomes lighter, creating low pressure; cool air is denser, creating high pressure.
2. Wind blows from high-pressure to low-pressure regions.
3. Fast-moving air exerts less pressure than slow-moving air (this is why roofs can blow off in high wind).
4. A cyclone forms over warm ocean waters when moist warm air rises rapidly, creating a low-pressure system with strong rotating winds.
5. Safety during a cyclone: stay indoors, keep away from windows, follow official advisories.

Why does a thatched roof sometimes fly off during a strong storm?

Fast winds above the roof create low pressure there, while air pressure below
the roof (inside the house) remains higher. This pressure difference pushes
the roof upward and off.

• Thinking wind blows from low to high pressure (it's the opposite).
• Assuming all storms are cyclones — cyclones specifically form over warm oceans with a rotating structure.
• Forgetting that hot air rises because it is less dense, not because it is "lighter" in an unrelated sense.

• Does air move from high pressure to low pressure, or the other way?
• Name one safety measure to take during a cyclone warning.

Open the Practice tab for graded questions on Winds, Storms and Cyclones.