You need:
NOW IT FLOWS, NOW IT DOESN'T Air pressure can both prevent and help water to flow out of a bottle. Let us see how
a plastic bottle a needle a suitable vessel with water
How the experiment is performed: 1. Pierce a number of small holes in the bottom of the bottle. 2. Immerse the bottle in the water vessel to fill it. 3. Plug the opening with you thumb and take the bottle out. What will happen: The water will not flow out of the little holes. Why? Due to the pressure of the air on the holes. When you remove your thumb the water will begin to flow - this time the pressure being exerted on it is both that of the water itself and of the air. Use these bottles as watering cans.
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