How To do

One of most popular scientific equipment than has been invented is the Cartesian Diver, receives this name in honor to the great scientist and French philosopher René Descartes (1596 - 1650). In this occasion we presented this simple equipment (that it has more than 300 years of antiquity), is possible to be realised of many forms; one of most common consists of using a glass bottle with mouth widens whose interior has filled with water and a small frasquito with the same placed liquid mouth down. The mouth of the great bottle is closed with a rubber piece. When pushing the rubber is obtained that the frasquito lowers within the great bottle.


  • A great glass
  • A disposable soda water bottle of plastic transparency of 2 liters
  • Gotero of glass or plastic
  • Water
  • Small rubber globe
  • Hot silicone in bar
  • What is necessary to do?

    We fill the bottle with water. Also we filled with water the glass but without rebalse. We take gotero and we absorb water of the glass, but only the sufficient thing as so that as soon as floats in the water of the same glass. If one sinks we must leave saves a little water and to return to test, with this already we will have a Cartesian Diver.

    We put the diver, that is to say gotero, within the bottle and we covered it.


    When tightening the bottle with our hands increases the pressure in its interior, which compresses the air within gotero, when being compressed the air is reduced its volume. This leaves space so that more water enters gotero. The diver increases of weight and it sinks. When the pressure in the bottle is reduced, the air volume within gotero increases. This forces to that it leaves water gotero and, when reducing its weight, gotero raises. We do not have to forget that the water is incomprehensible, that is to say, that it is not possible to be compressed as the air.

    In a submarine really it happens the same. The submarine has empty compartments in its helmet, called ballast. When these are opened, they fill of water and the submarine submerges when increasing of weight.

    When the water is pumped outside ballasts by means of compressed air tanks, that it takes the own submarine, this one reduces its weight, by having lost the water and comes out ahead.

    When the bottle is not pressed, the water inside gotero equals the pressure of the air. Gotero does not raise nor low.

    When the bottle is pressed, the water, that has not been able to be compressed for pressure on the air and it compresses it, with this the water enters to the interior of the tube of gotero and this it is put heavier and low.

    Video that shows the construction of the cartesian Diver step by step

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