Liquid drop Model.

Liquid drop Model;

Bohr proposed this model because of some basic similarities between nucleus and a liquid drop. There is analogy of cohesive forces between the molecules in the liquid with the short range attractive force between the nucleons in the nucleus. The assumption of liquid drop Model are given below:

1) The nucleus was assumed to be an incompressible sphere just like a liquid drop. The nuclear density is independent of nuclear volume as that of a liquid drop. Unlike the liquid drop, the nuclear density is also independent of nuclear matter.

2) The nuclear forces between the nucleons is independent of charges. It is a short range force and is attractive in nature.

3) The spherical shape of liquid surface is due to symmetrical surface tension forces which acts towards the centre of the drop, the nuclear forces are similar in this case. Inside the nucleus, the nucleons are attracted from all sides equally but on the surface the nucleons are attracted downward as there is no nucleons above the surface. Therefore under such condition one can conclude that these forces are analogous to surface tension.

4) The binding energy per nucleon is constant just like the latent heat of vapourisation is a constant quantity for a liquid.

5) The nucleons in the nucleus move about the spherical enclosure called the nuclear potential barrier just like the molecules of liquid move about in the spherical drop of liquid.

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