An eddy in a bottle

To make our experiment we need two plastic bottles of one and a half litres.

First, drill a hole in the two bottles corks.
Then, fill one of the bottles with water to about three quarters and join the two plugs per cylinder.
To unite the two bottles it can be used a tape.

It is very important the union between the bottles.

When the water on the bottles is empty is upper, it seems that the water does not fall easily to the bottle bottom, but if we give a circular motion to the bottle top and creates a swirling, water falls easily.

By placing the bottles on top, water doesn’t fall to the bottom because of the compressed air trapped in the bottle which is down. It can pass through it, as there is no room for it.

When the eddy is generated by moving the top bottle, it is communicated the air in both bottles and the water in the top bottle falls easily into the bottom bottle.

by Yulia

A whirlpool in a bottle

Materials:


Two bottles made of plastic 1,5 l.
Insulating tape

Execution:

First, we make a 1 cm hole at the tops of the bottles. Then, we fill one of the bottles with 75% of water and join the bottles by means of the tops. To join the two bottles we use the insulating tape. This joint is very important, so do not be stingy with the insulating tape.


When the bottles with water is on top of the other, the water does not fall easily to the empty bottle, but if we make a circular movement with the upper bottles, it generates a whirlpool, and the water falls easily.

Explanation:

When we place the bottles full of water on the top, the water does not fall because of the low compressibility of the air, which takes up the lower bottle and does not let any space for the water to fall.
By the time, the whirlpool is generated by the air of the two bottles that passes from one to the other and the water of the upper bottle falls easily.

By Mercedes and Fátima

An eddy in a bottle

In order to make our experiment we needed two plastic bottles of 1´5 liters.

In the first place, we perforated a hole of 1 cm in the corks of the two bottles. Soon we filled one of the bottles with water until approximately three fourth parts and if united the two bottles by the corks. In order to unite the two bottles insulating tape can be used. Is very important a good union between the bottle.

When the bottle with water is on the empty bottle it is observed that the water does not fall easily to the inferior bottle, but if we give a circular movement to the superior bottle is generated an eddy and the water falls easily.

When placing the bottle in the superior part, water does not fall by the little compressibility of the air locked up in the inferior bottle that does not leave space to the water that falls. When the eddy is generated when moving the superior bottle, it is put in communication the air that is in both bottles and the water of the superior bottle falls easily in to the inferior bottle.

Colegio Sagrado Corazón (Esclavas)
Sevilla (Spain)