The word science comes from a foreign word scientia which, literally, means knowledge. But scientific knowledge is quite different from the knowledge contained in other areas. First and foremost, science believes in observation, experimentation and verification. If a particular scientist reports a new development, fellow scientists will not accept it unless his results are verified and found duplicable by them. Practical proof is the only parameter to test the validity of any scientific finding. Though science has greatly advanced from the days of the falling apple to the internet yet the basic guiding principles remain the same. Besides, science is self-correcting, i.e. it discards a finding which is not useful any longer and. It replaces it with a better, more plausible and acceptable scientific framework.
The last century has seen probably more dramatic scientific progress than any preceding century or even the last millennium. It may sound too fantastic to have a refrigerator telling you to order milk because it has been exhausted, or your going to a superstore to order the baby of your choice, but they seem to be possibilities quite visible in near future.
For convenience, we have divided our discussion into two, i.e. the physical world (dealing with non-living objects and the phenomena connected with them) and the living world, although a deeper study will reveal that such a division is purely artificial, i.e. biological and physical phenomena merge to produce the world as we see it.