Questions: Air Pressure and Wind

Question 1

What causes wind?

• A. Earth's rotation pushes air around the planet
• B. Trees and buildings redirect air flow to create wind
• C. Air flows from areas of high pressure to areas of low pressure to equalize the difference
• D. The Sun blows air across Earth's surface

Answer: (C)

Wind is fundamentally caused by differences in air pressure. When the Sun heats the ground unevenly, warm air rises (creating low pressure) and cool air sinks (creating high pressure). Air flows from high-pressure zones toward low-pressure zones to equalize the difference. The greater the pressure difference over a given distance, the stronger the wind.

Question 2

Why does warm air create low pressure and cool air create high pressure?

Model answer: Warm air molecules move faster and spread apart, making warm air less dense. This lighter air rises, leaving fewer air molecules near the surface — which means less pressure pushing down (low pressure). Cool air molecules move slower and pack closer together, making cool air denser. This heavier air sinks, creating more molecules near the surface pushing down (high pressure).

This density difference is the engine of atmospheric circulation. Uneven heating of Earth's surface by the Sun creates warm and cool areas, which create pressure differences, which create wind. This convection process drives weather patterns from sea breezes to global wind systems.

Question 3

Air pressure increases as you go higher in altitude.

• T. True
• F. False

Answer: False

Air pressure decreases with altitude. At the surface, you have the entire weight of the atmosphere above you pressing down. As you climb higher, there is less atmosphere above you, so the pressure drops. This is why your ears pop on an airplane — the pressure outside decreases as the plane climbs, and your ears adjust to equalize the pressure.