Lesson 9 of 14
Fast air, low pressure
Show on a big screenTwo paper strips hang about one hand's width apart. You blow between them. Do they move apart or together? Balloons do the same.
Step 1 of 4
- Two balloons are tied a little apart. The air around them is still.
- You blow air up along the gap. The air there moves fast.
- The fast air has lower pressure than the still air outside.
- The higher pressure pushes the balloons together.
The rule
The strips move together. The balloons do too.
Air moves from high pressure to low pressure.
Rule: Fast-moving air has lower pressure than still air beside it. The higher pressure pushes things towards the fast air.
Wind can lift a weak roof. Air above the roof is fast. It has lower pressure than the still air inside. The higher pressure inside may push the roof up.
Stay safe
In a storm, stay inside a strong building. Do what adults and officials say.
Blow harder. Watch the balloons.
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Try the lab to finish this lesson.