ABSTRACT
If we do not try to nd any correlation between different phenomena, then for every event we have to nd a different law. But if we can correlate these events, then we nd that only a very few laws can explain most of these phenomena. These correlations lead us to the concept of symmetry. Consider a spherical ball. One can visualize it by taking its projection from all orientations, which will give us an innite set of data. However, if we consider its spherical symmetry, we can visualize it from only one direction and get all the innite projections from all orientations by making spherical transformations. Children develop such a notion of symmetry in their mind just by observing. But they will not try to understand that the spherical symmetry of the object means that this object has the minimum surface area and any loop on the surface of the sphere can be contracted to a point. Neither do they try to nd out the meaning of spherical transformations. So, the concept of symmetry can be understood at different levels and can have different applications as well. The mathematical tool to study symmetries is the group theory which we discussed in chapter 3.
