also includes the angular momentum of one particle orbiting another particle, such as an electron orbiting the nucleus of an atom. Don't worry about isospin, it doesn't have anything to do with this article. Isospin was an idea that was introduced in the 1930s. It is a property of some particles such as protons and neutrons. These particles are now known to be composed of quarks and isospin is understood in terms of these quarks. A fantastic article and eye-opener for a layman also. A great job done as science in higher degree should not be the privilege of a few, but it should touch the understanding of the common public as a whole. Your articles have just done this. I must congratulate you for popularisation of the science for the common public. Please send such articles as it gives me the understanding required to let it disseminate. Thanks with a lot of regards. D.J.Borthakur, Jorhat, Assam, India. U had stated that boson does not change its state whereas fermions changes it state.If such be the case how can helium 3 which is a fermion does not change its state and retains its normal state at 2.17 degrees above absolute zero, when compared to helium 4 which becomes a superfluid at temperature 2.17 degrees above absolute zero inspite of being a boson? Bosons like to be in the same state (or energy level) as other bosons. Fermions can't be in the same state. When used in this way the word