Explain why water can be poured into a bottle with a narrow neck with the aid of glass tube?

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propertiesoffluids

#1

In order to fill a glass bottle of narrow neck, if water is allowed to fall on the opening of the neck of the bottle, the pressure of air inside the bottle and strong force of adhesion acting between molecules of water and glass as compared to weak force of cohesion between water molecules do not allow the water to enter into bottle.
To pour water into a bottle of narrow neck, place a part of one glass rod inside the bottle. Allow the water to fall in small amounts on the portion of rod, outside the bottle. As force of cohesion between water molecules is less than the force of adhesion between the molecules of glass and water, the water molecules cling to the glass rod and move into the bottle along the rod under the pull of gravity.