Weather and Climate
Winds, storms and cyclones
Trace a wind back to a difference in air pressure, and follow the chain from a rising column of warm air to a thunderstorm and a cyclone.
Let go of the neck of a blown-up balloon and the air rushes out. Puncture a bicycle tube and the same thing happens. In both cases the air inside was at a higher pressure than the air outside, and it moved until the two matched. Wind is that, on the scale of a coastline.
Where wind comes from
Air moves from a region of high air pressure to a region of low air pressure. Warm air is lighter, so it rises and leaves a low-pressure area behind it; cooler air from the higher-pressure regions around moves in to take its place. The bigger the pressure difference, the faster the air travels.
Worked example
Why does a breeze blow inland from the sea during the day, and back out to sea at night?
During the day, land heats faster than water, so the air above the land becomes warmer and lighter.
The two surfaces are taking in the same sunlight but land warms more readily than water. That difference is the engine for the whole thing.
Try it together
Two balloons are joined by a straw: one blown up tight, one limp. Predict what happens, step by step.
One or two words is enough for each answer.
1.The inflated balloon holds air at the higher pressure. Which way does air travel — from high pressure to low pressure, or from low to high?
Have a go
Have a go on your own. A storm that is accompanied by lightning and thunder has a name of its own. What is it? Give the one word.
Ready to practice?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.