Bernoulli's Law - Demonstration.

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As air is blown down the middle of the opening an area of low pressure is created. This low pressure comes about due to the fast moving air. Surrounding air is sucked into this area of low pressure. So the majority of air that fills the balloon does not come from one breath but from the surrounding air.

Bernoulli's Law Demonstration
Bernoulli's Law states that *Fast flowing air creates an area of low pressure while slow moving air creates relative high pressure.* This law underlies the fact that a large plastic bag can be totally inflated with just one breath. Hold the end of the bag tightly against your lips and attempt to inflate the bag. You find that it takes several deep breaths to complete the task. Click to see the video
Now hold the plastic bag open and blow air down the middle of the opening. You find that the bag inflates with just one breath. Explain why, using Bernoulli's Law. Click to see the video. Solution
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